“The Valley of Vision:” a Brief Commentary.

“The Valley of Vision;” a Collection of Puritan Prayers & Devotions, Arthur Bennett(ed.)

Then shall ye call upon me, and ye shall go and pray unto me, and I will hearken unto you.

And ye shall seek me, and find me, when ye shall search for me with all your heart.

Jeremiah 29: 12-13

 

In this blog, I’ll be taking a brief look at a small book of prayer, written by the faithful from ages past.

 

Tune in soon for details……

 

De Fideli.

Book Review: “The Story of the Cosmos.”

Putting God back at the centre of all things.

“In the beginning God created the heavens and the earth” Genesis 1:1. With majestic simplicity the author of the opening chapter of Genesis thus differentiated his viewpoint not only from the ancient creation myths of Israel’s neighbors, but also effectively from pantheism, such as is found in religions like Vedanta Hinduism and Taoism, or twentieth century process theology, and from polytheism, ranging from ancient paganism to contemporary Mormonism. The biblical writers gave us to understand that the universe had a temporal origin and thus imply creatio ex nihilo in the temporal sense that God brought the universe into being without a material cause at some point in the finite past.

William Lane Craig( pp183)

 

 

Title: The Story of the Cosmos, How the Heavens Declare the Glory of God

General Editors: Paul M. Gould & Daniel Ray

Publisher: Harvest House Publishers

ISBN: 978-0-7369-7736-4

Price: US $22.99/ UK £18.65

 

Eloquent, profound, powerful – here’s a beautiful and sweeping affirmation of God’s breathtaking creativity”

Lee Strobel, New York Times bestselling author of The Case for a Creator.

 

Contibutors: Dr. Luke Barnes, Dr. David Bradstreet, Dr. Brother Guy Consolmagno, Dr. William Lane Craig, Terry Glaspey, Dr. Paul M. Gould, Dr. Guillermo Gonzales, Allen Hainline, Dr. Holly Ordway, Daniel Ray, Dr. Sarah Salviander, Wayne R. Spencer, Dr. Melissa Cain Travis, Dr. Michael Ward.

 

Every now and then, a new book comes along which captures the essence of what it is to be an intellectually fulfilled Christian. Our Creator not only brought this Universe into being without a material cause, but also designed it with exquisite precision so that living creatures such as ourselves could explore its deepest mysteries through the media of science, art, music, poetry and fantasy literature. Using wonderful prose and beautiful illustrations, The Story of the Cosmos, sets a very high bar that will delight anyone who cares to read and consider its message. The central theme of the book is derived from the famous claim made by the Biblical King David, asserting that:

The heavens declare the glory of God; the skies proclaim the work of his hands.

Psalm 19:1

One of the most egregious claims made by modern expositors of scientific materialism(scientism) is that science and Christianity represent ‘non-overlapping magesteria,’ so that one system of knowledge cannot inform the other. Yet it is instructive to remind the Biblical ignoramus that to be a Christian is to value and seek truth. After all, did not our Lord remind us of such?

I am the way and the truth and the life. No one comes to the Father except through me.

John 14:6

So, simply put, to follow the truth is to follow Christ.

The Story of the Cosmos is the brainchild of an American school teacher and amateur astronomer, Daniel Ray, who managed to canvass the opinions of a stellar line up of Christian intellectuals across a dozen disciplines, ranging from theology to high-energy astrophysics. What unites all these authors is their passion for conveying the intellectual rigour of the Christian faith and how it inspired some of the finest minds in the history of human thought,  who clearly (and correctly!) viewed the created order as a manifestation of a mind infinitely more advanced than our own.

The book is divided into three parts;

I The Exploration of the Cosmos

II Expressions of the Cosmos in Art and Literature

III Evidences Pointing to the Creation of the Cosmos

 

In Part I, the authors explore the vastness, beauty and power of the cosmos and how these attributes provide solid clues to the nature of the Personhood who created it all. After a great opening chapter by Daniel Ray, laying the foundations of the themes to be developed in the book, Christian apologist and biologist, Dr. Melissa Cain Travis, makes a very powerful case for believing that the universe in which we find ourselves in is rational because its Creator(the God of the Bible) is also rational. Exploring ideas by Galileo Galilei, Johannes Kepler, Max Planck, Albert Einstein, Thomas Nagel and Alvin Plantinga, Travis, shows that naturalistic explanations of the origin and the Universe and life are almost certainly false. This is followed by a curious essay by planetary scientist and Catholic padre, Dr. Brother Guy Consolmagno, who reveals that science in general, and his study of meteorites in particular, is a way of “growing closer to the Creator.” Consolmagno’s work is a labour of love, he explains, where he is piecing together the exquisite machinery by which God created the worlds.

Studying the minutae of creation brings one closer to God, says Guy Consolmagno.

Part I continues with a highly entertaining essay by the professional astronomer, Dr. Guillermo Gonzalez, co-author (with Dr. Jay Richards) of the highly acclaimed book, Privileged Planet, demonstrating how our world shows the undeniable hallmarks of design but also goes further to show that where humanity finds itself on the outskirts of a vast spiral galaxy like the Milky Way, cannot be the product of idle serendipity, but rather must reflect the Creator’s desire for us to explore His creation using the methods of science and the high technologies we derive from it.

Following on from this, another professional astronomer, Dr. David Bradstreet, explores the majesty of the stellar Universe in all its diversity, focusing our attention on the light curves of a variety of eclipsing binary stars and how these allow him to get up close and personal with God’s illustrious creation. Bradstreet shows us clearly how stars evolve through time because there is a robust physical theory underpinning those claims, in contrast to Darwinian evolution, which is not entertained in this book (I’m guessing that all of the authors are now sceptical of those claims!)

Studying the light curves of eclipsing variable stars reveals the machinery of creation, according to David Bradfield.

Chapter 5 of Part I, written by astrophysicist, Dr. Sarah Salviander, presents a fascinating look at how the history of astrophysics and cosmology and their progress to becoming robust modern sciences, were often hampered by influential intellects who turned away from properly reasoned deductions just because it clashed with their world view. Salviander showcases the disputes that arose between Sir Arthur Eddington and his brilliant Indian graduate student, Subrahmanyan Chandrasekhar (Chandra). Although Eddington admired Chandra’s theoretical achievements, he refused to accept where his conclusions concerning the fate of massive stars (neutron stars and black holes in particular) would lead him. Salviander writes:

The answer is that Eddington fell victim to some combination of the four primordial barriers to understanding that are constantly at work in the minds of every person; limited perspective, misleading emotions, intellectual inertia, and excessive pride. Humans try to observe the Universe from the confines of the surface of Earth, which I can tell you from first-hand experience is always difficult. People find some ideas comforting and others disturbing, and those emotions often get in the way of the search for truth. Longstanding and popular ideas are often difficult to overcome even when compelling evidence like Chandra’s is presented. And, sometimes people like Eddington experience a lapse in humility that causes them to use their authority to oppose an idea they just don’t like.

pp 94-95.

 

Salviander also highlights the antics of the nuclear physicist, J. Robert Oppenheimer, who also went down the same road Eddington did.

“A close friend of Oppenheimer’s, the Nobel laureate physicist Isidor Isaac Rabi, believed that Oppenheimer’s abilities as a physicist suffered as a result of his turning away from the beliefs of the Old Testament in favour of the literature of Hindu mysticism. According to Rabi, Oppenheimer was scientifically blinded by an exaggerated sense of mystery and the boundary between the known and the unknown,  and became incapable of following the laws of physics “to the very end.” pp 95.

Salviander concludes that for many people, the Biblical God is “far greater, far more mysterious and uncomfortable even than black holes. We can’t see or touch God, but as with black holes, we have reason to believe something or someone immensely powerful is there. But for many people the notion of God is even more unsettling than black holes because anything with the power to create the universe has to be vast and powerful beyond our ability to imagine.” pp 105

In the final chapter of section I, physicist Wayne R Spencer, provides a historically accurate overview of the life and work of Johannes Kepler and Tycho Brahe, both devout Christians, whose talents and shortcomings as human beings often complemented each other. Far from “the boot camp mentality” of Protestant theology deliberately distorted by materialists like Carl Sagan in his best-selling book, Cosmos, Spencer clearly shows that these men considered astronomical discovery to be a powerful mechanism for better understanding the character of the Creator, who established all of the physical laws of the universe at the beginning of time.

Part II of the book kicks off with a wonderful essay by the American theologian, Terry Glaspey, who explores the relationship of art with the starry cosmos. As a scientist, I personally found this chapter to be fascinating and deeply enriching, as much of the content was previously unknown to me. Glaspey writes:

If the out-of-doors is a grand natural cathedral, then the artist can invite people who stand before their work to enter that cathedral, their brush-strokes pointing like fingers toward the glory of God to be found there.” pp 133.

Glaspey explains that while early Christian art concentrated on themes derived from the gospels, during the Romantic period(roughly the first half of the 19th century), “nature was widely embraced as the language of God.” pp 135

“Wanderer Above the Sea Fog” by Caspar David Friedrich(1818).

Glaspey proceeds to highlight some of the artistic works of various artists including Caspar David Friedrich(1774-1840), Thomas Cole(1808-1848), Fred Edwin Church(1826-1900), George Watts(1817-1904) and Vincent van Gogh(1853-1890).  According to Glaspey:

“...science and art are telling the same story about the mysterious glory of the cosmos……just two different ways of seeing the same wondrous things.” pp 147

Michael Ward, a professor of apologetics and Senior Research Fellow at Oxford, presents the next chapter of the book, which takes an in-depth look at arguably one of the greatest apologists for the Christian faith in the 20th century; C. S. Lewis, whose works of fiction and non-fiction address the Christian world view in all its richness.Ward explores Lewis’ circumspect interest in the development of science but who utterly rejected the notion that science was the only system of knowledge that can convey deep truths. In other words, Lewis was an admirer of science but strongly rejected scientism.

The next and final chapter of Part II, written by Dr. Holly Ordway, a professor of English, describes some of the work of another literary giant of the 20th century, J.R.R. Tolkien, whose many works of fiction also have a strong underlying Christian theme. But in this work, Dr. Ordway places a special emphasis on Tolkien’s lesser known work, The Silmarrion, and how its language and imagery is strikingly similar to themes developed in the Bible. As Ordway claims, “The Silmarrion is in many ways very much like the Old Testament. It is written in a formal, “high” register that evokes the language of the Bible….Linguistically, then, he provides us with the familiar made strange so that the strange has the potential to become familiar.” pp 179

The final part of the book looks at scientific evidences for God’s existence. The opening chapter, written by internationlly respected apologist, Dr. William Lane Craig, takes a close look at the doctrine of creatio ex nihilo and its centrality to the Christian faith. Although Craig is not a scientist, he nonetheless shows an excellent grasp of the conceptual ideas  developed by cosmologists over the years. Prior to the discovery of the expansion of the universe, many atheist scientists considered the universe to be eternal, with no beginning and no end, but after astronomers discovered several lines of evidence supporting hot Big Bang cosmology(red shifts of the galaxies, the cosmic microwave background radiation and the ratio of hydrogen to helium abundances that emerge naturally from hot Big Bang models), they were faced with the uncomfortable prospect(philosophically repugnant?) that the universe had a finite age, exactly as the opening line of the Book of Genesis claimed all along:

In the beginning God created the heavens and the earth.

Genesis 1:1

Lane Craig explains that attempts by atheist cosmologists like Lawrence Krauss to explain away the beginning, has been summarily rejected on both scientific and philosophic grounds. In his provocatively titled book, A Universe from Nothing, Krauss has a very odd idea of what ‘nothing’ entails, such that it is easy to see that the ‘nothing’ Krauss tries to pull over his readers’ eyes is actually something, whether it be a quantum field or some such. Indeed, Dr. Lane Craig, in perusing the many reviews of Krauss’ book, quotes the opinion of the distinguished philosopher of quantum physics, David Albert, who had the following to say regarding Krauss’ nothingness:

“….vacuum states are particular arrangements of elementary physical stuff…the fact that some arrangements of fields happen to correspond to the existence of particles and some don’t is not a whit more mysterious than the fact that some of the possible arrangements of my fingers happen to correspond to the existence of a fist and some don’t. And the fact that particles can pop in and out of existence, over time, as those fields rearrange themselves, is not a whit more mysterious than the fact that fists can pop in and out of existence, over time, as my fingers rearrange themselves. And none of these poppings….amount to anything in the neighborhood of creation from nothing…” pp 197

Indeed Albert concludes that “Krauss is dead wrong and his religious and philosophic critics are absolutely right.”

So much for a universe made out of nothing!

The next chapter, wriiten by physicists Dr. Luke Barnes and Allen Hainline, is particularly embarrassing for the High Priest of Darwinian pseudoscience, Richard Dawkins, who famously quipped:

The Universe that we observe has precisely the properties we should expect if there is, at bottom, no design, no purpose, no evil, no good, nothing but blind, pitiless indifference. DNA neither knows nor cares, DNA just is. And we dance to its music.

Barnes and Hainline walk us through the overwhelming evidence for fine-tuning evident at every scale from the sub-atomic world right up to the realm of the galaxies. Showcasing the various values assigned to the physical constants of physics, they show that only a very narrow range of those values are compatabile with life as we understand it. And those who wish to embrace the highly speculative ‘multiverse,’ must also concede that it too cannot avoid the issue of fine tuning.  Eventhough the authors do not bring God into the picture, their assessment of Dawkin’s bold assertion is clearly stated in their conclusion:

“This claim is false. A universe with, at bottom, no design and no purpose would be dead. Almost certainly. No structure, no useful energy, no galaxies, no stars, no planets, no chemistry, no complexity. Instead, as we look around us, we find a universe with something good at bottom: the capacity for life.” pp 219

 

The last chapter of the this section, composed by philosopher and Christian apologist, Paul M. Gould, describes the cumulative crisis in atheist material thinking as a kind of intellectual poverty that is dead to all that is beautiful, meaningful and awe-inspiring. In discussing what it means to be a being made in the image and likeness of its Creator, there are very strong motivations, Gould argues, to return to the “older, God-bathed and God-infused way of looking at the world.” More specifically, he argues that in order to be see the world accurately, we need to see it as it’s Creator(Jesus Christ) did.

“How does Jesus see reality? ” he asks, “As sacred. As a gift. As enchanted,” he asserts.

In perusing the writings of the other contributors to this book, Gould makes a persuasive case for believing that the physical attributes of this vast universe are such that they allow not only for human existence, but also for the flourishing of our kind as well as the other life-forms that inhabit our planet. He writes:

“A flourishing life is one in which the full assortment of natural capacities are activated, employed, and perfected. Plants have nutritive and growth capacities and a flourishing plant actualizes these capacities to realize its own good…..When it comes to humans we find a full panoply of capacities (in addition to growth and sensing) for reasoning, imagining, relating, acting, creating, moralizing, judging and more.Many of our capacities are not needed, at least not obviously, to the extent(in range and depth) for mere survival. yet we find those capacities present in us along with the general possibility of their actualization.” pp 230

Gould uses this line of reasoning as a platform to reject methodological naturalism in favour of theism. He continues:

“The following argument from fittingness helps us see the rational preferability  of theism to naturalism;

1. The fact that the universe is finely-tuned for the existence and flourishing of humans is not surprising given theism.

2. The fact that the universe is finely-tuned for the existence and flourishing of humans is surprising given naturalism.

3. Therefore, it is probable that theism is true.”

pp 232

In contrast, Gould considers evolutionary explanations for human flourishing as shallow at best and ill-thought through at worst. What is more, Gould asks a pertinent question:

“How can we recapture the Platonic-Aristotelian-Christian way of looking at things?”  pp232

Gould finds his answer in the revolutionary writings of St. Paul in 1 Corinthians:

“Paul helps us imaginatively understand the meaning of the universe. The hope of eternal life is pictured for us every day and night as we look around and see the immensity , beauty, diversity, and fittingness of creation. Just as the earthly and heavenly bodies each have their own splendor, so too(by analogy) will our imperishable bodies. Importantly, notice that the heavenly bodies – the Moon, the planets, the stars -perform for us a sacred duty, helping us to imagine a deep mystery, the mystery of our future ressurection in Christ.” pp 233.

Gould urges the reader to see the universe as God intended us to see it. All of reality is part of what Gould calls “God’s unfolding drama…. a drama in which everything fits together in order to display the manifold wisdom, goodness, and power of God, who is, “all in all“. pp 233.

The Story of the Cosmos ends with an afterword by Daniel Ray. The full glory of the night sky is the last great frontier which has been drowned out by light pollution from human designed cities. As a result the majority of people alive today never really see the full majesty of the stellar universe like our ancestors did. Ray suggests that we need to re-connect with this great wilderness in the sky in order to begin a journey back to our rightful place as the stewards of God’s creation. Watching the stars does not necessarily mean buying a telescope or any other optical device; we can use the eyes God gave us to watch the stars as they wheel across the vault of heaven. Like our forebears, we can study the stars to mark the progress of time and the march of the seasons, just as our Creator intended us to do.

The Scriptures quoted in the main text.

It was a great pleasure to read this beautifully composed work of Christian literature. It is thought-provoking, reverent and inspiring, with great apologetic appeal. In an insane world, where everything we once considered good and noble is being overturned by narcissistic, immoral, godless and aggressive secularists pulling the strings of government and poisoning the minds of our young people, The Story of the Cosmos is a refreshing oasis for the human soul, waiting patiently for the return of our Lord & Saviour, Jesus Christ.

 

Neil English is the author of seven books in amateur and professional astronomy.

 

 

De Fideli.

 

Spectrum

Take a Closer Look.

 

 

In this blog, I’ll be exploring subjects of general interest/concern to me and wider society in this age of mass deception:

The Dark Side of Transgender Medicine

 

How the Media Manipulates Truth

 

Cogito ergo sum

 

The Secular Case Against Homosexuality

 

Our Fragile Home

 

The Anti-Social Network

 

A Form of Child Abuse

 

Cool stuff you never hear in Church

 

The Rise of Homeschooling

 

James Clerk Maxwell: a Great Life Lived

 

Reasonable Faith: An Interview with Professor Alvin Plantinga

 

Doubting Dodgy Science

 

Evaluating World Views

 

Depraved Minds

 

The Beauty of the Creation

 

The Preciousness of Free Speech

 

Walking your Way to Good Health

 

Did the Eye Really Evolve?

 

Unholy Alliance: when Dodgy Science Merges with Theology

 

RTB Classic: The Truth about UFOs

 

The Rise of Neo-Paganism

 

From Spiritual Shipwreck to Salvation

 

The Rise in Euthanasia Killings

 

The Greatest Story Ever Told

 

Holocaust Survivor

 

Coming Soon to a Town Near You: The Rise of Bestiality

 

The Death of Naturalism

 

Anything Goes

 

From Gaypo to Paedo

 

When Scientists Lose the Plot

 

The Sixth Mass Extinction Event in Our Midst

 

‘Depth Charging’ the Values of the Ancient World

 

The Truth about the Fossil Record

 

AI

 

The Language Instinct

 

Not the Same God

 

Greening the Deserts

 

Moving the Herds

 

Evolutionary Atheist gets his Facts Wrong…..Again

 

Distinguished MIT Nuclear Physicist Refutes Scientism

 

Pursuing Truth

 

The Dangers of Yoga

 

Pseudoastronomy

 

 Humanist Guddle

 

Get thee right up thyself! : The New Transhumanist Religion

 

The Biblical Origin of Human Rights and why it’s a Problem for Atheists

 

A Closer Look at the Israeli-Palestinian Conflict

 

Winds of Change: Prestigious Science Journal Concedes Design

 

A Distinguished Chemist Speaks the Truth

 

The Scourge of Pornography

 

Eye

 

Bart Ehrman Debunked

 

An Evil Generation Seeks After a Sign

 

Magnetic Pole Shift

 

Decimation of Global Insect Populations

 

The Spiritual Suicide of a Once Christian Nation

 

Mass Animal Deaths Worldwide

 

Not Going Anywhere

 

UN Report: World’s Food Supply under ‘Severe Threat’ from Loss of Biodiversity

 

False gods of the New Age

 

From Abortion to Infanticide in the “Land of the Free”

 

Sports Personalities Speak Out Over Transgender Athletes

 

Magonus Sucatus Patricius

 

Celebrating a Killing

 

Human “Out of Africa” Theory Debunked

 

The Other Side of the Rainbow

 

Vintage James Tour: How to Cook Up a Proto-Turkey

 

Big Brother Watching

 

Follow the Evidence: The Problem of Orphan Genes

 

Follow the Evidence: The Genius of Birds

 

The Butterfly Enigma

 

Man’s Best Friend

 

Darwinian Evolution On Trial Among Biologists

 

New Fossil Finds Thwart Human Evolutionary Predictions

 

Global Persecution of Christians

 

 Ratio Christi

 

Questions About the Qur’an

 

Engaging with Islam

 

Calling Evil Good

 

Parousia

 

Secular Humanism as a New Religion

 

Tall Tales From Yale: Giving up Darwin.

 

More on the Proto-Turkey:  Dr. Tour Responds to Cheap Shots from the Pond Scum Merchants

 

Good Riddance: Despicable British TV Show Axed after Death of Participant

 

There’s Heehaw Out There…ken.

 

The Fastest Growing Insanity the World has Ever Seen

 

Pharmakeia

 

Darwinism & Racism: Natural Bed Fellows

 

The Modern Root of Anti-Semitism

 

Jesus & Archaeology

 

A Victory for Common Sense: Transgender Weightlifter Stripped of his Medals

 

The US Equality Act: A Plea for Caution

 

Reunited: Music & the Human Spirit

 

Gladys Wilson

 

1st Century Christian Insight: The Didache

 

The Clothes Maketh the Man

 

Why Some Books were Left Out of the Bible

 

Why the Human Mind is not Material

 

What God Thinks of Scientific Atheism

 

For the Love of the Creator

 

An Essential Component of a Modern Education

 

US Supreme Court Overules Calls by Militant Atheists to Demolish a World War I Peace Cross

 

Earth: “Presidential Suite” of the Universe

 

How to Really Stand Out in a Crowd

 

Straight from a NASA Scientist: Jewel Planet

 

The Singularity

 

No Life Without Super Intelligence

 

Darwinism as a Cargo Cult

 

Body Plan Development Raises New Headaches for Evolutionists

 

Membrane Biochemistry Stymies Evolutionary Origin of Complex Cells

 

Overwhelming Financial Response for Israel Folau’s Unlawful Dismissal by Rugby Australia

 

Science Speaks: Common Abortafacients Harmful to Both Mother & Child

 

Biblical Ignoramus Twists the Words of Christ

 

The Multiverse: Just Another Religion

 

Apologia Part I

Part II

Part III

Part IV

Part V

Part VI

 

Attention Parents: American Psycho Association Promoting Polyamory to Pre-Teens as ‘Ethical.’

 

The Only Rainbow God Recognises

 

Calling Time Out on Evolutionists’ Failure to Explain The Cambrian Explosion

 

7 Reasons to Reject Replacement Theology

 

Psychiatric Diagnoses are ‘Scientifically Meaningless’ Study Shows

 

Out of a Far Country: A Gay Son’s Journey to God

 

Universalism Debunked

 

The Prosperity Gospel Debunked

 

New Science Reveals First Cellular Life to be “Amazingly Complex”

 

New Law Firms Being Established to Counter the Rise in Christian Persecution

 

Playing the Numbers 32:23 Game

 

Multiple Lines of Scientific Evidence Converge on 3rd Century BC Age of the Famous Isaiah 53 Scroll.

 

Meet the Gestapo

 

Exposed: Theologians Deceived by Darwinian Ideology

 

New Insights into the Shroud of Turin

 

What we Know and Do Not Know About the Human Genome

 

Amazonia Burning: Facts Versus Media Speculation

 

Debunking Da Vinci Code Tosh

 

Sorry: No Such Thing as “Gay” Penguins

 

Genetic Entropy

 

Dunderheid Alexa

 

The Extinction of Reason

 

A Biblical Perspective on Diet

 

Portrait of a Second-Rate Barnacle Collector

 

Revelation: Number of Transgender People Seeking Sex Reversals Skyrockets

 

Chasing Materialists out of Town

 

Climate Change: Tempering Media Hysteria with Facts

 

Psychologist Debunks Pseudoscientific Explanations for Human Love & Compassion

 

The Dismantling of the Feminine

The War on Truth: The Triumph of Newtonianism Part II.

Taking the aperture advantage in grab ‘n’ go astronomy.

Continued from Part I

New entries indicated by ***

Of late I have been observing primarily with my 8” f/5.9 reflector.  After collimation, I check the seeing via visual observation at moderately high power on tight and/or magnitude contrast doubles—this is how I happened on this pair of doubles in Draco.

STT 312AB and STF 2054AB appear to the naked eye as the single star Eta Draconis.  Starting in Ursa Minor, a straight-line path from Kochab through Pherkad gets me to Eta as shown in the annotated Cartes du Ciel screenshot below.

 

DRADblDblPath_GIMP.jpg

 

I like to start with the fainter pair, STF 2054AB which is  a mere 12’ due North of Eta Draconis.  In 2017 this mag 6.2/7.1 pair had a separation of 0.943”, which is in line with historical speckle data.  At 345x, I saw two whitish stars of slightly uneven magnitude that were clearly split with dark space between the stars.  I gauged the seeing by estimating how often the image sharpens to two distinct discs.

The 2nd Ed. of CDSA lists STF 2054 as a (2) + 1 triple, meaning the A component is really AaAb.  Stelle Doppie informs the AaAb pair is CHR 138AaAb with a separation of 0.222” (1990)—perhaps those with larger glass can see this as oblong?

Moving on to the brighter object, Eta Draconis or STT 312 AB is where the fun starts.  This mag 2.8/8.2 pair has a separation of 4.68” as measured by Gaia satellite (2015.5)  Using the same eyepiece you used for STF 2054AB, try to find the faint secondary without prior position angle knowledge.  It will be quite small and about 4.5x farther than the distance between the stars comprising STF 2054AB. 

My first attempt at detecting STT 312 B required almost a half hour of moving my eye from averted to direct vision before I definitively saw the tiny speck of light corresponding to the companion.  On a subsequent night, I found the secondary right away because I knew where (and how) to find it.  The more steadily the diminutive B presents as a dot of light, the better my seeing.  Of course, darker skies will also aid your efforts for seeing the faint companion. 

STF 2054AB and STT 312AB help me gauge my local seeing and are fun to look at.  Have you looked at these stars lately?

Nucleophile(Austin, Texas, USA): from an online thread entitled, Fun in Draco: Proximal Pairs STT 312AB and STF 2054AB

Perhaps the aforementioned objects are too easy and you desire a greater challenge; if so, head about 11 degrees due south of Eta Draconis to Hu 149

This pair of ~matched magnitude 7.5 stars has a separation of 0.66″ (last precise in 2017 = 0.665″; my own measure in 2017 = 0.662″)  The pair are slowly widening:  Burnham (1978) lists the separation at 0.5″

Using my 8″ reflector, I observed this object last night and logged the following observations:

345x:  image transforms from elongated to notched (snowman) about 30% of the time; both stars are light orange-yellow

460x:  now seen as sitting on the border of resolved to two discs and split with the tiniest of black space between the discs

Below is an inverted image of Hu 149 I assembled in 2017 using my 15″ reflector and an ASI178MC camera at f/23 operating in mono mode.

 

HU149_JDSO.jpg

Nucleophile(Austin Texas, USA), from an online thread entitled; Fun in Draco: Proximal Pairs STT 312AB and STF 2054AB

Attached are some recent pictures of these double stars.  In all cases, N is up and E is left.

I obtained the images using my 15″ reflector and an ASI 290MM cooled CMOS camera.  An imaging train of Paracorr type 1 (setting 5), Powermate 2.5x and a Baader Orange filter gives an f ratio of 13.3  Images were collected using either SharpCap or Firecapture. 

Measures were made with Speckle ToolBox.  Composite images were assembled in Registax.

First up is STF 2054AB

STF2054AB_DRA.jpg

Dear Mark,

Thanks a lot for your interesting and well-documented presentation of a pair of doubles so well suited to gauging seeing  all year round. Last night I made these my first port of call with a 140mm Maksutov (an OMC 140 made by Orion UK, a good instrument). The physics suggest that the separation of 0.943” which you state for STF 2054AB is at the physical limit possible with this aperture, so I was keen to find out how I would fare.

The day had been hot, seeing was mediocre. I know from experience, though, that the air may calm down in certain phases of the evening, so I just hoped I would catch a good moment. At 75x I saw no hint of a companion of Eta Draconis, but STF 2054AB was definitely elongated. At 130x still no sign of Eta’s companion, but the elongation of STF 2054 became even more evident and it was clear at which end the weaker component stood. Encouraged by this, I went up to 210x. Now STF 2054 was a stretched figure-8 that popped apart into separate discs in better moments of seeing. Somehow quite charming!

I had gone in without PA knowledge and estimated this at 330°. Stelledoppie says 351°. So deviation <10%, that’s OK.

After having trained the eye in this manner, I turned my attention to Eta Draconis at 210x. All I could spot was a disc within a wildly dancing diffraction pattern. Although the B component, with its separation of 4.68”, is more than 4.5x further than the distance between STF 2054 A and B, it is evidently much harder to spot. This was an interesting lesson in the effect of Delta-Mag.

I find STF 2054 quite charming and Eta quite challenging, and will certainly be returning to them often. So thanks again, Mark.

CS, Christopher

C.Hay(Germany), from an online thread entitled; Fun in Draco: Proximal Pairs STT 312AB and STF 2054AB

Finally, here is Hu 149

I measured this one 21 times over three nights in order to gauge repeatability of the measuring protocol.  The current measure matches very well what I obtained a few years back.

Hu149_DRA.jpg

rugby, on 19 Jun 2019 – 06:11 AM, said:

I just finished observing STF 2054 AB and STT 312 in Draco using an  SW 120 ED and a Meade LX 10. A very bright moon with Jupiter brightened the eastern horizon.  Unfortunately these pairs lie directly above my house and thus suffer from heat rising from the roof.

What I saw was surprising. 2054 was elongated but not separated in the 120 at 200x.  I had not expected anything because it is on the edge of this scope’s capabilities. I did not try the 8 inch.

STT 312 AB was exceedingly difficult. Without prior knowledge of PA I kept seeing flashes of a tint dot south south preceeding the primary. I used the 120 at 200x. The view in the 8 inch was too turbulent for any resolution.

I am notoriousy poor in estimating position angle.

Hi Rugby,

Give ’em a try with your 8″–I think you will like the views!

Nucleophile( Austin Texas, USA), from an online thread entitled; Fun in Draco: Proximal Pairs STT 312AB and STF 2054AB.

Last night was about my 10th try to find that little bugger hanging out in the diffraction ring. I had tried repeatedly and without success with my 120mm ED. I’ve tried before with my 8″ [Newtonian], even on an EQ platform a few nights ago. This time I managed to see it with the 8″ at an ungodly 498x without the EQ, so constant nudging and then allowing it to drift (if the drifting was near rapids) . I would call it my “great white whale”, but it’s more like a tiny white pimple.

You’d expect the 8″ should easily split it, if I could just get improved seeing.

Chesterguy

Chesterguy( Stillwater, Oklahoma, USA), from an online thread entitled: Zeta Herculis…finally!

 

Well, I confirmed my sighting of Zeta Herculis las night. Same instrument, equal or better seeing and this time on my EQ Platform. Despite not getting my platform aligned perfectly on Polaris because it was blocked by my house, I still managed enough accuracy so that, while it drifted through the EP, it wasn’t like the prior night. Still a tough split at 498x in my typical seeing. I salute those of you who are splitting it below 140mm.

Chesterguy(Stillwater, Oklahoma, USA), from an online thread entitled: Zeta Herculis…finally!

I observed this double with the 8″ reflector twice in recent days:

345x:  just split with smaller secondary appearing yellow against bright white primary; secondary appears to be sitting between first and second diffraction rings

314x:  when seeing permits, the yellowish secondary is seen sitting atop the primary

I did a few Aberrator simulations for the expected view using either my 8″ or 15″ reflectors; these are shown below.

 

ZetHERAberrator_Gimp.jpg

The 8″ inch simulation is fairly close to what I saw.  The 15″ simulation shows the secondary now sitting near the second diffraction ring.  In some images I obtained recently with the 15″ and an ASI 290MM camera this is pretty much what I saw.  In the composite image below the first diffraction ring appears as a fuzzy halo while second ring got washed out a bit in processing.

 

STF2084_Zeta_HER.jpg

Nucleophile(Austin, Texas, USA), from an online thread entitled; Zeta Herculis…finally!

I just made a 7 inch aperture stop today for my 18. Worked great tonight. I’ve made them many times before but it’s been a while. Seeing tonight was so good the better views were at full aperture..

Darren Drake(Chicago, USA), from an online thread entitled Aperture Mask

DavidC, on 19 Jun 2019 – 03:41 AM, said:

I am making an off axis aperture mask for my 10 inch lightbridge, but using a single 4 inch hole. I got the idea from san francisco sidewalk astronomers, but they had it as plans for a solar filter. I’m making it for planets and double stars. I’ve been told by stepping the aperture down to 4 inches, planets won’t be as bright, therefore I can use more power on them. At 1270 mm focal length, I’m hoping for impressive views on planets by using more power. Am I thinking this correctly?

 

Thanx, David

Waste of time IMO. I have a 10” LB with a very good mirror set. I also have excellent 100 and 120 mm ED refractors. If seeing is equal, the 10” reflector slaughters the excellent refractors in planetary detail.

SteveG(Seattle, Washington, USA), from an online thread entitled: Aperture Mask

Vla, on 20 Jun 2019 – 2:55 PM, said:

Smooth edges have more of a cosmetic effect. Rough edges don’t induce aberrations, because they don’t affect wavefront shape, and unless the edge is ridiculously rough, the diffraction effect will be negligible. As an illustration, effect of a 2-inch focuser protruding into the light path of a 200mm diameter mirror. As much as 1 inch into the light path will take only about 1% of the energy out of the central maxima (which, expectedly, becomes somewhat elongated, because the vertical mirror diameter is effectively shorter).

Yes indeed! The effects are diffractive and tiny, not what we optics guys call aberrations. I also like your focuser signature there… Fourier Transform (impulse-response) says it all.

Masks roughly-cut with scissors or a knife are perfectly fine. The one thing to try to avoid is long straight edges. Those will give noticeable spikes. The three straight edges of the focuser there… do a little bit of that.

On the tech/theory side… there are infinitely many wavefronts that will produce the same impulse response. That’s because the sensor (eye or camera) detects only amplitude, but not phase. So you can’t inverse-transform back to the wavefront by processing on the one image of a star… unless you use two or more (ideally many) focus positions’ images. And that is what we call ~phase diversity analysis~ (what was used to assess Hubble’s flaw). And what is implicitly involved in the various casual ~Sar Tests~ that we often talk about here. 

Tom Dey(Springwater, New York, USA), from an online thread entitled: Aperture Mask

Deep13, on 14 Dec 2018 – 06:56 AM, said:

In my mind, the ideal planet telescope is a 10 or 12″ EQ Newt (split ring?) in a permanent location with a clear view of the south and overhead. Add a good binoviewer, pairs of long ZAOs, and an easy way to reach the EP, and I’d be all set. In reality, it would be too expensive and I have no place to set it up permanently. So-o-o-o, I’ve arranged to buy a used 8″ f/8 EQ-mounted Newt. I’ll need to have some servicing done on the mirrors. I’m thinking that within the realm of likely possibility, this may very well be my ideal set-up. Right now it has no fan and a tall R&P focuser, so I may change those things. And I’ll built a cart for the Meade RG mount. I already have a tall adjustable chair and a Denk II with pairs of TV Ploessls.

 

Any thoughts? What’s your ideal planet scope?

 

I had both a very good 8″ Zambuto f-7.5 and a 10″ Waite f-5.8 on an EQ mount, the 8″ I had rotating rings but still a very big pain in the rear to use on an EQ mount. I am considering a slightly different set up 10″ f-5.3 through f-5.5 for a shorter tube and mounted on an EQ-AZ mount, in AZ mode viewing will be far more easier as the EP will be on one side and accessible.  At the focal lengths mentioned as long as you get a premium mirror and build it well you can achieve 50x per inch with sharp image on the planets, and you can use a 1.83″ secondary, CO 18.3%. good luck.

dag55(Hamburg, Illinois, USA), from an online thread entitled; Ideal Planetary Scope

The Orion 4.5 in f/8 dobsonian could be an option. Seems to get good reviews on the optics here on CN. Lightwieght. I believe the focuser is plastic, but, it should be ok with normal weight 1.25in eps.If the moon with a 4 -5 in reflector is the ojective, this little scope should do a decent job.I have not used the Orion, however, I do have a 4.5in f/8, and I think they are capable little scopes.

Good viewing,

dmgriff, from an online thread entitled, 4-5” reflector recommendation

 

+1 on the AWB OneSky.

I was surprised at how well it works. At 14 pounds total, it might be just what you’re looking for.

Havasman( Dallas, Texas, USA), from an online thread entitled: 4-5” reflector recommendation

The AWB One Sky is fine for the money but its burdened with an very poor helical focuser, preferable is the Lightbridge 130 , discontinued but still available from some dealers, the Zhumell 130, the best of the bunch IMHO or the slightly smaller Zhumell 114 , very similar to the Orion Starblast but less money, the Zhumell is also sold as the Edmund Astroscan Millenium, D.

Binojunky, from an online thread entitled: 4-5” reflector recommendation

 

The Onesky is a fine scope. I have no problem with the focuser.,and the mount is quite stable.,Some of my best spent astro money.,cheers.,

Attached Thumbnails

  • 20190327_183143.jpg

 

Clearwaterdave(Western Maine, USA), from an online thread entitled: 4-5” reflector recommendation

How is a 4″ apo a “no brainer” when the OP specificly asked about a reflector? The OP has other scopes and seems to have some idea of what he’s lookin for.,What scope you think would do a better job for doubles or planets is not what he asked about. If you have used and liked a 4-5″ reflector of any type and you want to share your experience here that would be helpful to the OP.,waytogo.gif

Clearwaterdave(Western Maine, USA), from an online thread entitled: 4-5” reflector recommendation

I have had the OS up next to a 102ed and “to my eyes” the views are too similar for me to say either one was “better”.,And there are many many very happy OS owners.,So yes.,you can expect a quality reflector for $200.,That’s the no brainer.,and the OS isn’t the only one.,there are a few good quality 5″ reflectors out there for $200.,YOMV.,

Clearwaterdave(Western Maine, USA), from an online thread entitled: 4-5” reflector recommendation

Thank you again for all the great responses. I’m always pleasantly surprised at the information you guys have and your experience. Yes, optics are my primary concern for the scope, but I haven’t really read one bad review concerning them so I think the OneSky is what I’ll go with. I have a pretty large back deck with a decent view to the south so it will be easy to track the moon every night, even if only for a few minutes. Concerning refractors: the truth is I have little experience with them (I know they’re not hard to figure out) and my comfort level, if you will, is with Dobsonian type reflectors. I have a neighbor down the road who has a 4” Takahashi (I think), and the views through it are really something else. Then he told me the price tag and my mind went to how how big of a Renegade or Teeter I could get for the same price. Plus someone told me that owning a refractor will lead you down to the perilous and very expensive road of astrophotography.
The reason I don’t put the 8” out on the back deck is that I use it specifically for planetary viewing now. I have it in the garage ready to load up for a quick drive into the foothills next to the house. The view is better and I get away from all the house and street lights. At f/7 that 8” gives just wonderful views of the planets. I was also able to complete the AL double star program with. If you haven’t looked at that program, I recommend it as it was one of my favorites to do. The 8” was the first scope I ever owned and I had to rebuild it out of disassembled parts, which I found at a flea market. That was a journey, let me tell me you. But now it’s dialed in with a great mirror and I’ll have it forever.
And with the 10”: that’s my deep-sky, dark site, fall into the heavens scope. I try to get out there at least once, if not twice, a week. It too has great mirror and makes it hard for me to financially justify a larger scope given there’s so much to see with it.
Back to the OneSky. Hopefully it will be what I’m looking for. I have perfect cover and place for it, it won’t get dirty, and when I’m out enjoying the late evening and want a quick peak, it’ll be right there.

Mick Christopher, from an online thread entitled: 4-5” reflector recommendation

One of my all-time favorite 4ish inch scopes is the Orion XT4.5, mentioned by Dave and Ed earlier. It’s a very nicely engineered and accessorized product, and provides sharp high power views with very minimal focus wiggles and immediate dampening times. The long focal length makes the scope forgiving of the somewhat imprecise focuser, which works quite well. It’s also very easy on simple eyepieces, which is handy. It’s not a do-all scope, owing to the focal length and 1.25″ ep limitation, but it’s still capable of providing pleasant low power views, yet shines at moderate and high powers. Add a 5 gallon bucket, inverted, as a “chair” (which can pull double duty as a caddy for charts, ep case, and binos) , and the scope works well for adults without the need to raise the scope on a platform.

KerryR( Midwest Coast, Michigan, USA), from an online thread entitled: 4-5” reflector recommendation

 

If the OP can handle the extra size and cost the Orion XT6″F8 is a fine scope, I picked mine up last years for $300 Canadian brand new shipped to my door, take it out in two pieces, plonk it on the ground and away you go, D.

Binojunky, from an online thread entitled: 4-5” reflector recommendation

 

This report is the third installment of a series of observational investigations I have made using an 8 inch f/5.9 reflecting telescope. 

Check out this link for goals and methods used in this study:

https://www.cloudyni…-and-monoceros/

Corvus
Bu 920 (12158-2321) mags 6.86/8.22; pa = 308°; sep = 1.934”, 2016 (solid data)
345x:  well split with secondary a bit smaller; both stars are yellow; well above resolution limit

B 1716 (12247-2004) mags 9.42/9.42; pa = 230°; sep = 0.701”, 2014 (solid data)
345x:  single star
460x:  a bit elongated, but never resolved despite best efforts; below resolution limit; important data point to set lower limit for fainter stars

Hydra
STF 1273 AB, C (08468+0625) mags 3.49/6.66; pa = 310°; sep = 2.824”, orbital estimate for 2019.3 (solid data)
345x:  easily split to two yellow stars of widely varying magnitude; above resolution limit

Bu 587 AB (08516-0711) mags 5.75/7.41; pa = 121°; sep = 1.186”, 2017 (solid data)
345x:  blur of light that sharpens to a small secondary that is just split
460x:  spit 100% of time; above resolution limit

Bu 219 (10216-2232) mags 6.70/8.52; pa = 186°; sep = 1.773”, 2015.5 (Gaia DR2, solid data)
345x:  split 100% of time; secondary is much smaller and both stars are white; above resolution limit

A 3064 (08403-1518) mags 9.15/9.00; pa = 357°; sep = 0.681”, 2015.5 (Gaia DR2, solid data)
345x:  just resolved to two tiny discs 40% of time; just above resolution limit; important data point to helps set minimum value of rho for faint, equal mag pair

A 338 (08207-0510) mags 8.83/9.39; pa = 17°; sep = 0.569”, 2015.5 (Gaia DR2, solid data)
345x:  slightly pointy
460x:  slightly elongated, but never resolved; well below resolution limit

HJ 4478 (11529-3354) mags 4.67/5.47; pa = 52°; sep = 0.578”, 2015 (data needs confirmation)
627x/orange filter:  elongated that becomes notched 10% of time; just below resolution limit; difficult due to low altitude; requires re-measure to firm up separation value

B 1175 (10582-3540) mags 8.25/9.23; pa = 251°; sep = 0.61”, 1998 (data is old, scant)
345x:  resolved 50% time to two similar magnitude yellow stars; a bit above resolution limit; separation likely greater now; requires newer measures of separation and delta mag

B 218 (12002-2706) mags 9.11/9.69; pa = 340°; sep = 0.472”, 2015.5 (Gaia DR2, scant data)
627x:  very faint; rod shaped at times, but no hint of resolution or notch; well below resolution limit; requires re-measure to firm up separation data

HWE 72 (12136-3348) mags 6.48/8.55; pa = 159°; sep = 1.231“, 2016 (solid data)
345x:  just split 30% of time to two white stars; secondary is much smaller; above resolution limit

Bu 411 (10361-2641) mags 6.68/7.77; pa = 303°; sep = 1.33”, 2017 (solid data)
345x:  just split 100% time to two light yellow stars of somewhat dissimilar magnitude; above resolution limit

Bu 219 (10216-2232) mags 6.70/8.52; pa = 186°; sep = 1.773”, 2015.5 (Gaia DR2, solid data)
345x:  split 100% time; secondary is much smaller and both stars are white; above resolution limit

Leo Minor
STF 1406, aka STT 211 (10056+3105) mags 8.37/9.42; pa = 219°; sep = 0.728”, 2017 (solid data)
345x:  just split from resolved 30% time; stars are faint, white, and seem to be of similar magnitude; above resolution limit; a newer delta mag measure desired

Lynx
STT 159AB (06573+5825) mags 4.45/5.50; pa = 236°; sep = 0.704”, orbital estimate for 2019.3 (solid data)
345x:  single star
460x:  possibly pointy
627x:  at times elongated showing secondary as smaller, but never resolved; below resolution limit; it is unclear why this is so difficult—perhaps there is a ‘brightness’ factor that needs to be incorporated?  Revisit next year using orange filter and get a new measure.

COU 2607 (07441+5026) mags 5.33/8.43; pa = 164°; sep = 0.973”, 2012 (data is a bit old but is considered solid)
460x:  secondary pops into view as just split 50% of time; just above resolution limit

STT 174 (07359+4302) mags 6.62/8.26; pa = 92°; sep 2.170“, 2015.5 (Gaia DR2, solid data)
345x:  split 100% of time; both stars are white and secondary is much smaller; fine mag contrast double; well above resolution limit

Hu 850 (08094+3734) mags 9.42/9.23; pa = 349°; sep = 0.57“, 2016 (scant data)
345x:  viewed for an extended period of time using averted vision shows the pair exhibiting a notch just past extended a mere 10% of the time; never resolved and is considered below the resolution limit; a re-measure of separation is needed

Ursa Major
STT 232AB (11151+3735) mags 8.02/8.90; pa = 243°; sep = 0.623”, 2015.5 (Gaia DR2, solid data)
552x (Pentax 2.5XO/Paracorr Type 1, setting 1):  pointy about 25% of time, but never a hint of being resolved; below resolution limit

STT 235AB (11323+6105) mags 5.69/7.55; pa = 44°; sep = 0.949”, 2019.3 (orbital estimate, solid data)
345x:  on the resolved/split border with secondary seen as much smaller
460x:  cleanly split; primary is yellow, secondary is light orange; above resolution limit

STF 1770 (13377+5043) mags 6.93/8.18; pa = 128°; sep = 1.722“, 2015.5 (Gaia DR2, solid data)
345x:  cleanly split; primary is light yellow while the smaller secondary is light orange—a fine pair; above resolution limit

STT 200 (09249+5134) mags 6.53/8.57; pa = 337°; sep = 1.251”, 2015.5 (Gaia DR2, solid data)
345x:  close split (AV helps to see fainter secondary)
460x:  easily split to two stars of unequal magnitude—very nice; above resolution limit

STT 232AB (11151+3735) mags 8.02/8.90; pa = 243°; sep = 0.623“, 2015.5 (Gaia DR2, solid data)
552x (Pentax 2.5XO/Paracorr Type 1, setting 1):  pointy about 25% of time, but never a hint of resolution; below resolution limit—important data point for calculator development

A 1346 (09591+5316) mags 8.84/9.66; pa = 179°; sep = 0.624“, 2019.3 (orbital estimate; data is incongruent between orbital estimate, historical speckle and Gaia DR2)
345x:  slightly elongated; very difficult
460x:  moves past elongated to notched <10% of time
627x:  possibly seen as resolved 10% of time with averted vision; just below resolution limit; requires re-measure to firm up separation value

STT 229 (10480+4107) mags 7.62/7.92; pa = 254°; sep = 0.63“, 2019 (estimate from 4th Interferometric Catalog; data incongruent between historical speckle, orbital estimate and last precise)
345x:  moves past pointy to resolved 30% of time showing secondary as a bit smaller versus the primary
460x:  persistent snowman shape that sharpens to nearly split 30% of time; just above resolution limit; re-measure of separation needed for this important data point

Bu 1077AB Dubhe (11037+6145) mags 2.02/4.95; pa = 336°; sep = 0.802“, 2019.4 (orbital estimate, solid data)
460x/orange filter:  very difficult; secondary pops into view 30% of time as just split—otherwise, it is merely a blur of light/brightening of first diffraction ring; at or just above resolution limit

**Have you observed or imaged any of these objects recently?  Let me know.  Perhaps you have a suggestion for a double I should observe—I’m all ears!

Nucleophile(Austin, Texas, USA), from an online thread entitled; Investigations With an 8 Inch Reflector. Part I: Canis Major, Canis Minor, Lepus, and Monoceros

My preference is in the “or” category. I have used all of my scopes for doubles, but I love my 10 inch reflector… it is a double star magician… except for Sirius B… just can’t get that one in the 10 inch. But I have split it ONCE with my 4 inch achro (retired this one to give to my granddaughter)… she loves doubles too…

SeaBee1, from an online thread entitled; scope preference for doubles

I use my Stellarvue 105mm APO most of the time for doubles wider than 1″ and when the seeing is only fair.  It gives such nice images with no central obstruction.

If the seeing is above average I use the Intes 180mm Mak-Cass with its astro-sital 1/9 wave optical system on the tighter doubles, and planets.

I don’t usually use the 10″ LX 200 on doubles, but one night when the seeing was very good I was using the Baader 8-24 zoom on the double double in Lyra and zoomed all the way to 660x,  the stars looked perfect and the separation was enormous.

I usually don’t use my 18″ Obsession for doubles, but once while doing a two star alignment on Antares with my 12.5mm cross-hair eyepiece, there it was a bright orange star with a little green orb next to it.  I hade to just stop and take a good long look, it was beautiful, and so was the seeing that night.

Astromaster; from an online thread entitled; scope preference for doubles

Last seen this star for a long time. Seeing that the closer stars that I knew are either already inaccessible (too close) or have gone beyond the horizon, I decided to observe those that are less mobile. In particular, this one. Since there are days with an excellent atmosphere and they should be used. In comparison with the double in the zet boo, this star looks obviously wider and accessible. It is interesting that the difference in the sizes of fragments of diffraction disks is visible. This is quite unexpected, considering that the difference in brightness is only 0.2. Maybe this star is variable? and therefore I see that parts of diffraction discolves of different sizes (this happens when the difference in brightness is more than 1 … 1.5 magnitudes). This is weird.  I used a large piece of paper to accurately mark the track of the star and its position. Such dimensions allowed me quite accurately, without using devices, to note how exactly the disc is stretched..eta crb1.png
Constantin 1980, from an online thread entitled: Observation Eta CrB (0,38 “) 9\04\2019

This report is the fourth installment of a series of observational investigations I have made using an 8 inch f/5.9 reflecting telescope. 

Check out this link for goals and methods used in this study:

https://www.cloudyni…-and-monoceros/

Bootes
BU 224 (14135+1234) mags 8.94/9.35; pa = 95°; sep = 0.65“, 2015 (last precise; not solid, opening)
345x:  single star
460x:  pointy but never resolved; well below resolution limit; magnitude data is from Hipparcos (1991, 515nm); needs a re-msre of delta mag and separation

 

STT 287 (14515+4456) mags 8.40/8.62; pa = 5°; sep = 0.575“, 2017 (last precise vs 0.659” orbital estimate for 2019.3; data incongruent)
345x:  seen as elongated 30% of time
460x/averted vision/extended viewing:  elongated only, never resolved; below resolution limit; needs a re-msre of separation

 

STF 1866 (14417+0932) mags 8.48/8.65; pa = 205°; sep = 0.733“, 2015.5 (Gaia DR2, solid data)
345x:  on the border of resolved and split to two even magnitude light yellow stars; above resolution limit

 

STF 1863 (14380+5135) mags 7.71/7.80; pa = 60°; sep = 0.654“, 2017, (last precise, solid data)
460x/orange filter/averted vision/extended viewing:  moves past elongated to resolved 20% of time
627x/orange filter: just resolved 50% of time; just a bit above resolution limit; important data point (equal mag pair) to set minimum value of rho

 

STF 1867 (14407+3117) mags 8.36/8.83; pa = 355°; sep =0.674“, 2017 (data needs confirmation)
460x:  just split 50% of time to two white stars of slightly dissimilar magnitude; need re-msre of separation

 

A 148 (14220+5107) mags 8.32/8.96; pa = 190°; sep = 0.535“, 2019.3 (4th Int. Catalog estimate vs 0.58” last precise in 2015; data not solid)
627x:  a bit elongated but never resolved; well below resolution limit; need re-msre of separation

 

KUI 66 (14148+1006) mags 5.44/8.43; pa = 111°; sep = 0.99“, (my own measure in 2017 with ASI 178MC camera; data tentatively considered solid as it is a match with 4th Int. Cat. estimate)
627x/orange filter:  much smaller secondary seen as a resolved dot very near first diffraction ring 30% of time; just above resolution limit; important, large delta mag data point so re-msre with ASI 290MM camera needed.  See image below.

 

AGC 6 (14339+2949) mags 9.81/10.30; pa = 133°; sep = 0.752“, 2015.5 (Gaia DR2, solid data)
345x/extended viewing:  seen as elongated rod, never resolved; very faint and difficult; below resolution limit; important data point to set ‘faintness factor’

 

STT 298AB (15360+3948) mags 7.16/8.44; pa = 187°; sep = 1.208“, 2019.4 (orbital estimate, solid data)
345x:  easily split to two small light yellow stars of similar magnitude; very pretty; above resolution limit

 

A 1110AB (14497+0759) mags 7.69/7.93; pa = 245°; sep = 0.692“, 2015.5 (Gaia DR2, solid data)
345x:  oscillates between resolved and split; both stars are yellow with secondary seen as smaller and *delta mag is likely >0.24
460x:  seen as split 100% of time with secondary possessing a hint of orange; above resolution limit; Gaia DR2 gives a delta mag of 0.67 which does not agree with Tycho value of 0.24—will attempt a measure of delta mag to rectify

 

Canes Venatici
STF 1606 (12108+3953) mags 7.44/7.93; pa = 145°; sep = 0.611“, 2019.3 (orbital estimate vs 0.627”, last precise in 2017; data not solid)
460x:  elongated but never resolved
627x:  moves past notched rod to resolved 20% of time; at or just above resolution limit; observation supports tighter value of rho [0.611”]; this is an important data point; will re-msre (possibly annually) to firm up value

 

STT 251 (12291+3123) mags 8.35/9.27; pa = 61°; sep = 0.781“, 2017 (last precise; data not solid)
345x:  just resolved 30% of time with secondary much smaller
460x:  just split 50% of time; a bit above resolution limit; faint secondary plays role in difficulty; re-msre of separation needed

 

STF 1768AB (13375+3618) mags 4.98/6.95; pa = 95°; sep = 1.656“, 2019.3 (orbital estimate; solid data)
345x:  well split, primary is white and secondary is light yellow and considerably smaller—a fine sight!  Above resolution limit

 

Coma Berenices
STF 1639AB (12244+2535) mags 6.74/7.83; pa = 324°; sep = 1.855“, 2019.3 (orbital estimate; solid data)
345x:  well split, primary is white and secondary is light yellow; very pretty mag contrast pair; above resolution limit

 

STF 1687 (12533+2115) mags 5.15/7.08; pa = 200°; sep = 1.18“, 2018 (last precise; solid data)
345x:  a bit past just split 100% time with secondary noticeably smaller; both stars are yellow; above resolution limit

 

COU 397 (12575+2457) mags 9.06/9.71; pa = 63°; sep = 0.70“, 2015 (last precise; solid data)
345x:  single star; faint!
460x/averted vision:  slightly elongated but never resolved; below resolution limit; important data point to establish ‘faintness factor’

 

A 567 (13328+2421) mags 6.21/9.71; pa = 256°; sep = 1.450“, 2015.5 (Gaia DR2, solid data)
345x:  secondary seen as split 50% time and appears as very small, very faint dot a bit past first diffraction ring of primary; above resolution limit

 

Ursa Minor
STF 1989 (15396+7959) mags 7.32/8.15; pa = 23°; sep = 0.67“, 2013 (last precise vs 0.603”, orbital estimate for 2019.4; data not solid)
345x:  moves past elongated to exhibit a snowman shape
460x:  resolved about 40% time with secondary a bit smaller; above resolution limit (observation supports separation closer to 0.67” value; re-msre of separation needed)

 

BU 799AB (13048+7302) mags 6.60/8.45; pa = 265°; sep = 1.39“, 2017 (last precise; solid data)
345x:  easily split; both stars are white and secondary is considerably smaller—very pretty; above resolution limit.

 

A 1136 (16135+7147) mags 9.22/9.47; pa = 9°; sep = 0.727“, 2007 (last precise, data is old)
345x:  barely split; both stars are very small and white, and secondary is just a bit smaller; helps to establish ‘faintness factor’; above resolution limit; a re-msre of separation is needed

 

Virgo
BU 797AB (12345+0558) mags 9.10/9.39; pa = 146°; sep = 0.61“, 2010 (last precise, data is a bit old but considered solid)
345x/averted vision/extended viewing:  slightly pointy
460x:  elongated and on the border of resolved, but never did resolve despite an extended view
627x:  moved past elongated to resolved about 5% of time; at or slightly below resolution limit; a very important data point that warranted 45 mins of study under very good seeing conditions

 

RST 4484 (11447-0431) mags 8.46/8.39; pa = 64°; sep = 0.738“, 2017 (last precise; data not solid)
345x:  just split to two ~even magnitude yellowish-white stars—beautiful!  Above resolution limit; re-msre of separation needed

 

BU 935AB (13459-1226) mags 5.66/8.47; pa = 304°; sep = 1.03“, 2001 (last precise; data is old)
460x:  brightening of first diffraction ring sharpens to much smaller secondary 30% of time; both stars are yellow; above resolution limit; a new measure of separation is needed for this important mag contrast binary

Have you observed or imaged any of these objects recently?  Let me know.  Do you have a suggestion for a double I should observe within one of these constellations?  I would like to hear about it.

Nucleophile(Austin, Texas, USA), form an online thread entitled, 8 Inch Reflector Investigations. Part IV: Bootes, Canes Venatici, Coma Berenices, Ursa Minor, and Virgo

Here is an image of KUI 66 I obtained in 2017 using an ASI178MC camera operating in mono mode.

 

KUI66_JDSO.jpg

Cool, another crop! Here’s some of mine for comparison:

STT 287, 552x 12.5”. Wow! Hair-split, ~0.7″, near equal or half a delta mag.

STF 1867, 552x 12:5”. 0.5 delta mag, hair to figure 8 split, white. Not especially good seeing

Kui 66: 12.5” Unresolved faint haze at 553x, but adding the apodizing mask I had a glimpse of the B star 15% of the time, very small and faint, ~3″ and 4-5 delta mag. Both orange. Definitely there.

STT 289: 8″ 205x: Noticed a very much fainter star emerge with averted vision then could hold direct. Very fine, well split. 8″ 410x: Tried to bring out the B star with higher magnification, but oddly it disappeared. Curious. 20″ 410x: B star easily seen though the disks are bloated, seeing not good.

STT 298. 12.5” 552x Wow! Almost didn’t look at this one since it was split in the 80mm finder. One component is a close equal pair, ~2″.

STT 251. 12.5” 553x: Decidedly not round disk — there’s also a brightening in the diffraction — but not really split.

STF 1768: 8″ 205x: Very tight pair, a little more than hairline split, ~2 delta mag. 8″ 333x: white and dull blue, ~1″, split, Nice!

STF 1768. 12.5: 553x: Very pretty pale yellow and orange, 2-3 delta mag, ~2″

STF 1639: 8” 205x White and slightly blue pair; close, around 3″ [overestimated the split, it was so clean!]

STF 1687: 12.5” 553x = 35 Com: Bright orange & fainter B, showpiece, ~1.5″

A 567: 12.5” 553x: very faint B, very close, ~1″ when seeing stills, 3-4 delta magnitude. Surprised it is not so difficult. B looks like it doesn’t have any light of its own and is illuminated by A.

BU 935 = 86 Vir: 12.5” Pretty orange star but @ 553x poor seeing won’t allow split of 3 delta mag, 1.2″ B.

mccarthymark(San Francisco Bay Area, California, USA), form an online thread entitled; 8 Inch Reflector Investigations. Part IV: Bootes, Canes Venatici, Coma Berenices, Ursa Minor, and Virgo

Excellent info, Mark.

my notes on your notes:

a.  STT 287, inclined to think it is tight–like 0.6″  I will def msre next year.

b.  the much studied KUI 66, nice use of mask to glimpse the companion!  I used an orange filter and very high power on an excellent night

c.  STT 289–I will add this large delta mag object to my list (thanks!)

d.  STT 298AB  something is askew here with the delta mag as both of us describe the mags as being similar–I didn’t catch this first time around but have made a note for next year to try and get a msre of delta mag for this one; I looked back into my log notebook and also noted:  “tiny headlights; beautiful!”  Additional note based on the 4th Int Cat.:  the same year as the Tycho mag values [as listed in the WDS] are those from Hipparcos (albeit at a slightly shorter wavelength = 511nm) which found  the magnitudes to be 7.59 and 7.78–a much closer match to what we observed.  This is humorous:  WDS notes say the ‘D’ component at 167″ is actually a galaxy (possibly a quasar)!  How’s that for ‘optical illusions’  At mag 14, I will be chasing that one for sure with the 15″ scope.

e.  STT 251 was surprisingly difficult for both of us…

f.  BU 935  you may wish to give this one another shot on a night of very good seeing; it is difficult

Nucleophile(Austin, Texas, USA), form an online thread entitled, 8 Inch Reflector Investigations. Part IV: Bootes, Canes Venatici, Coma Berenices, Ursa Minor, and Virgo

Here is a composite image of A 1110AB taken in 2017 with the ASI 178MC camera.  The image supports a delta mag of >0.24

My measured value differs quite a bit from that of Gaia DR2 (0.692″) for this object.

 

A1110AB_JDSO.jpg

Nucleophile(Austin, Texas, USA), form an online thread entitled, 8 Inch Reflector Investigations. Part IV: Bootes, Canes Venatici, Coma Berenices, Ursa Minor, and Virgo

    So much for Newtonians not being suitable for observing high-resolution double stars eh?

    Mr. Hardglass

     

    Sol, that the primary is 8.38″ in diameter is a revelation. I assumed it was the standard 7.9″. When I stow it away for the monsoon, I need to measure it. That’s kind of cool, but definitely non standard for a Newt, yea? I wonder if they are using 8″ SCT blanks that are (supposed to be) a little bit ‘over sized’. Just curious.

    When I do the math for a 2.6mm diagonal support, I get 2.6/8.38 = 31% obstruction. Not a ton of difference, but comforting to some. My MCT has a 30% +/- obstruction and offers no ill feelings. The images are nice. It should have the contrast of a 8.38 – 2.6 = 5.8″ refractor, and you do not hear folks complaining about those views. It still puts ~90% of the maximum light into the Airy disc compared to a perfect 5.8″ APO. It’s right at the diffraction limit with a descent (not premium) mirror.

    Abytec(Pampanga, Philippines), form an online thread entitled: ES Firstlight 8inch dob vs. Skywatcher 8inch dob

    Actually I took lots of measurements regarding the E.S. 8, and measured many times. Not because I was obsessively compelled to, but I had an opportunity to acquire another 8″ mirror with a “pedigree”. So I needed to know if I would be able to use the E.S with little if any modification for an actual 8″ diameter with a traditional 1.4″ thickness to work.

    To the original O.P. the stock E.S. primary is also 7/8″ thick so the 6 point floating cell is just another little plus for the E.S. over the GSO or Synta.

    With the stock E.S. 8 that’s well collimated and cooled Jupiter showed a bit better than TEC140 with really good, (8P) seeing. On D.S.O. no contest.

    Sol Robbins(astronomical author and distinguished sketcher), from an online thread entitled, ES Firstlight 8inch dob vs. Skywatcher 8inch dob

    Hi all,

    Please find attached a drawing of Jupiter I made last night with my 8 inch Newtonian in my home observatory.  I have to say, I was quite impressed with image quality- the details on the disk were easier to see despite the low altitude of the planet.  The main feature was the dark and turbulent SEB(s), and the start of the STropB in the South Tropical Zone.  The EZ was rather active as was the NEB, the NTB and NNTB contained darker sections.  Io is shown in the drawing and was probably the strongest colour I have ever seen, no doubt this is due to the low altitude.

    Best wishes,

    -Paul

     

    Jupiter_2019-06-29-0012UT_visual_PAbel.png

    Paul G. Abel(author, BBC Sky at Night presenter, Leicester, UK), form an online thread entitled: Jupiter and Io last night.

     

     

    From practical experience I have found optical quality, coating quality, proper baffling and eyepiece used more important to contrast than CO size once its below around 30%. Why small APO’s out perform slightly larger obstructed scopes is usually NOT due to being un obstructed but optical quality, mechanical quality and other factors. A smaller CO is nice, but can limit your fully illuminated field and eyepiece choice. Theory is great, but assumes everything is equal which it seldom is.

    The biggest enemy of contrast is scatter, stray light and optical quality if you have a reasonable size CO.

    Richard Whalen(Florida, USA), from an online thread entitled, Secondary Mirror Obstruction?

    TOMDEY, on 02 Apr 2019 – 9:46 PM, said:

    A six-inch scope with a 30% diameter obstruction resolves far better than an unobstructed five-incher. Just generate the non-normalized point-spreads and MTFs to see that in action!

     

    PS: This is why a (good) modest-sized Dobsonian will always blow the socks off a good smaller refractor (any smaller refractor!) for both light-gathering and resolution!

     

    But, gota admit… refractors make fine finder scopes on big Newtonian reflectors…    Tom

    Every time I see yet another thread about secondary mirror sizing and central obstruction (particularly when the MTF graphs start appearing), I say what Tom said above – just use a slightly larger telescope and don’t worry about it.  (And those little refractors do make very nice finder scopes.)

    However, I will also add something else – if you undersize the secondary or size it to only fully illuminate the very center of the field, then you are:

     1) using the part of the secondary that is most likely to have a defect,

     2) using the part of the secondary that might roll off due to cooling,

     3) using the part of the secondary that is often left out of the interferometric analysis, and

     4) forcing yourself into very precise placement of the secondary in order to get something close to a fully and symmetrically illuminated field (in other words, making it very hard on yourself for very little gain).

    My method to size secondaries for most telescopes is simple – add 4″ to half the mirror’s diameter to get the intercept distance.  Then divide by f/#.  Then go up one flat size if the calculation yields a size that is close to a standard flat size.

    So, if I calculate that a 3.1″ or 3.2″ flat is needed, I go to 3.5″.  At 3.4″ – 3.5″, go up to 4.0″.

    The 4″ added to half the mirror’s diameter just allows the use of a filter slide underneath a properly placed SIPS or Paracorr 2.  For a little more breathing room, use 4.5″ in the calculation.

    Try this on various commercial Newtonians and you’ll find that some have secondaries that are too small…..

    Mike Lockwood(premium large aperture mirror maker), from an online thread entitled, Secondary Mirror Obstruction?

    Whew! for my 36-inch F/3.75… that comes out to (18+4)/3.75 = 5.9″ … and mine is 6.25″, with a nice wavefront! And, frankly… even a tad bigger than that might be prudent. I just happened to already have the 6.25 and characterized the wavefront at work… figured a known good one would keep the project hustling along!  I then teased the focuser as close in as possible… reducing that four inches to about three. When I focus my farthest-innie eyepiece… only have a few mm to spare! 

    Tom Dey( retired optical scientist, Springwater, New York, USA), from an online thread entitled, Secondary Mirror Obstruction?

     

    A number of factors are working against reflectors:

    1. Reflectors have central obstructions, which reduce the resolution.There’s also a bit of loss to the spider, which creates diffraction spikes.

    2. Reflectors tend to have problems with temperature differentials within the tube, which creates air currents that distort the image.

    3. Mirrors have more scatter than lenses.

    4. Reflectors have a harder time staying in alignment than refractors.

    5. Reflectors have coma. Refractors have their own problems (chromatic aberration and spherical aberration) but expensive glasses and lens designs can basically eliminate these.

    6. Refractors are usually higher end than reflectors (so, they tend to be higher quality).

    However, you can usually resolve these:

    1, 3. Reflectors scale up far better than refractors, so they can have more aperture, which helps compensate for these problems. Obstruction sizes can be minimized, curved spiders will spread the diffraction spikes around and make them less apparent.

    2. Intelligent fan usage can do a lot for air current formation. Good telescope design can keep cool-down times reasonable and mostly eliminate this issue in use.

    4. It’s pretty easy to get good at reflector collimation. Just keep it collimated.

    5. Coma can be mostly eliminated through use of a paracorr. Or, you can use a longer focal ratio.

    6. There are premium mirror-makers who produce mirrors up to the quality of the best lenses.

    If you resolve these issues, reflectors still do not perform up to the standard of a refractor of the same aperture – but will perform as well as a refractor that is slightly smaller. However, you can get a reflector that is far larger than any refractor you can get. It’s reasonably feasible to get a 12-16″ dobsonian with premium optics and good thermal management, and that will (under good conditions) walk all over any refractor anyone with a normal income will ever be able to afford.

    Mitrovarr(Boise, Idaho, USA), from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    Refractors typically do not suffer from thermals, are typically in excellent collimation, are baffled better, and don’t have a center obstruction.

    The number of reflectors that are miscollimated is astronomical. So overall I think you have a better chance of having a excellent experience with a large APO refractor. BUT, find a 10″ or bigger 1/6th wave or better, perfectly collimated reflector and it will knock your socks off.

    Whichwayisnorth(Southern California, USA), from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    That Dalek, on 03 Mar 2017 – 01:35 AM, said:

    Just a question that came to me. Thanks for any answers!

    Refractors often have better definition, which is the ability to show fine, low-contrast detail.  A reflector solves that problem by being larger, gathering more light and having higher resolution.

    A old rule of thumb is that a 6-inch Newtonian, properly designed and built, will beat a 4-inch refractor.

    Caveman_Astronomer, from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    I will simply say that what we perceive as “sharpness” is not resolution.. A few comments, experiences, thoughts.

    – If I look at 52 Orionis, a 1 arcsecond double star in my 120 mm Orion Eon. It is very close to the Dawes limit so on a perfect night, the disks are overlapping and its difficult split at best. If I point my 10 inch F/5 Dob at 52 Orionis on that same night, and the scope is cooled and of course collimated, 52 Orionis is split wide open. Much smaller disks widely separated.

    In this case, I see 52 Orionis as much sharper in the 10 inch.. But most often, I think the comparisons of both contrast and resolution are made in relative terms, at a 0.5 mm what do I see?

    – Looking at the Globular M79 in Lepus is a 6 inch refractor versus my 22 inch Dob, few would perceive that the refractor was sharper.. M79 in the 22 inch looks about like M13 in a 10 inch. M79 in a 6 inch looks, well we know what it looks like..

    – Reflectors are fininky to the uniniated.. They require care and attention.. Collimation and thermal management are important..

    It always seems there comparisons are made between some sort of ideal refractor and the average faster Newt. An 120 mm F/5 achromats versus a 130 F/5 Newtonian.. I think most would (f)ind the Newtonian sharper…

    Jon Isaac(San Diego, California, USA), from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    mogur, on 04 Mar 2017 – 02:19 AM, said:

     

    dugpatrick, on 03 Mar 2017 – 01:53 AM, said:

    All good points.  But, yes, resolution is better with larger aperture.  An 8″ newt will have better resolution than a 4″ APO. And better CA.

     

    Doug

    Only if it’s PERFECTLY collimated! (a rare find) And I’ll take a little CA over loss of contrast because of a spider vane and secondary obstruction.

     

    Perfect collimation of reflectors is not hard to obtain, with the right tools (Glatter laser + TuBlug or Catseye cheshire + autocollimator).   But not every reflector owner is so demanding of collimation, nor willing to spend for the top-level tools that reliably produce perfect collimation.  OTOH, others of us are a bit happily OCD about collimating our reflectors.

    FirstSight(Raleigh, North Carolina, USA), from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    Apo refractors exist in a sweet spot where their unobstructed aperture and single-pass light path tends to produce better images than similar aperture reflectors in the same seeing conditions. Most amateurs view with seeing conditions that put anything larger than about ten inches at a disadvantage because the scope resolution is limited by the seeing, not the aperture. With steady seeing and constant temperatures (e.g. Florida) reflectors can do just as well as apo refractors for visual use.

    GJJim, from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    mogur, on 04 Mar 2017 – 02:19 AM, said:

     

    dugpatrick, on 03 Mar 2017 – 01:53 AM, said:

    All good points.  But, yes, resolution is better with larger aperture.  An 8″ newt will have better resolution than a 4″ APO. And better CA.

    Only if it’s PERFECTLY collimated! (a rare find) And I’ll take a little CA over loss of contrast because of a spider vane and secondary obstruction.

     

    The difference in inherent resolution between an 8-inch scope and a 4-inch scope is so vast that the Newt would have to have disastrously poor optics or be really badly collimated to flunk this particular test.

    Operating at the magnifications useable in a 4-inch APO, the loss of contrast due to the 8-inch Newt’s central obstruction is barely detectable.

    Tony Flanders(Former Sky&Telescope Editor, Cambridge, MA, USA), from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    osted 04 March 2017 – 08:23 AM

    Mitrovarr, on 04 Mar 2017 – 04:26 AM, said:

     

    grif 678, on 04 Mar 2017 – 03:43 AM, said:

    In all my old books, way back before APO’s and SCT’s. the rule of thumb seemed to be, in all instances, that a 3 inch refractor was about equal to a 6 inch reflector. I often wondered why, since a 6 inch mirror had so much more area than a 3 inch lens, but I guess the focal length and secondary obstruction had something to do with it.

    I wonder if that figure was due to worse coatings back in the day. I really wouldn’t expect a modern 3″ refractor (any kind) to beat a 6″ of equivalent quality. Even back in the day, I’m not sure. I have a really good long 3″ achromat and a good 6″ homemade (not by me) dob, both are at least 30 years old, and the dob totally destroys the refractor on planetary detail.

    I think one only has to setup and RV-6 alongside a 3 inch F/16 achromat to see that even 50 years ago,  a 6 inch Newtonian was far more capable than a 3 inch refractor… 

    Been there,  done that,  know the result,  don’t need to do it again.. 

    Jon Isaac(San Diego, California, USA), from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    We can confidently say that a well-made 4-inch refractor can do better than a well-made 4-inch reflector, but the issue gets a little murkier when we start looking for a refractor that is a serious competitor for a well-made 12-inch Newtonian, for example, or even for a well-made 8-inch Newtonian.

    Caveman_Astronomer, from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    So there I am with my 120 mm F/7.5 Orion Eon with the FLP-53 doublet that cost me $1200 used and next to it is a 10 inch F/5 Dob that cost me $240 used.

    Splitting doubles, the 10 inch does the number on the refractor, viewing Mars, the 10 inch does the number on the refractor. This should be no surprise. This does require an operator who knows how to clean a mirror, the collimate a scope, to cool a scope.. And it does require decent seeing..

    Inch for inch, there is nothing as potent as a small refractor.. Dollar for dollar, pound for pound, reflectors offer more planetary contrast, will split tighter doubles..

    Jon Isaac(San Diego, California, USA), from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    Refractors are great. Too bad they are all so small in aperture

    Caveman_Astronomer, from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    caveman_astronomer, on 04 Mar 2017 – 1:40 PM, said:

     

    Cpk133, on 04 Mar 2017 – 1:25 PM, said:

    God, or natural selection, depending on your persuasion, seems to favor refractive optics for wide fields, low maintenance, and the sharpest views per mm of aperture.

    What kind of refractor should I buy that would compete with a 12-inch Newtonian?

     

    This 10″ refractor should do the trick.  http://www.cloudynig…nch-tec-at-wsp/

     

    $50 000 + $15 000 for the mount and $8 000 for the tripod.

     

    Cotts(Madoc, Ontario, Canada), from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    russell23, on 04 Mar 2017 – 3:24 PM, said:

     

    treadmarks, on 04 Mar 2017 – 3:14 PM, said:

    People often say refractor images are more “aesthetically pleasing” (sharper?) even if they don’t show more detail. Aside from the quality issues mentioned, I’m thinking it’s also because smaller telescopes are more resistant to bad seeing. My understanding of the theory is that larger telescopes can have better contrast through brute-force, by having more clear aperture. So it’s not the contrast giving refractors more aesthetic images, it’s their smallness and the fact that refractors take the most advantage of that smallness.

    That certainly could be part of it.  Another factor for me is the simplicity of the observing.  I am able to sit at the back end of the scope and sight along the tube to locate objects or stars for star hopping.  The viewing is always comfortable like that and sighting along the tube with your eye next to the eyepiece is not as easy with a newt.

     

    Like I said – I’m not ant-Newtonian.  I might even look to pick up a large dob when I retire.  But for now I’m very happy with what I have.

    I think a Newtonian is actually easier to point.  Imagine an object 75 degrees elevation.  With a refractor,  it is very awkward to position my head to look along the tube or through a red Dot or Telrad finder.  With a Newtonian,  the focuser and finders are at the sky end of the scope,  I just lean over,  glance through the Telrad,  point the scope, comfortable and effective. 

    Jon Isaac(San Diego, California, USA) form an online thread entitled, Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    Quote

    I don’t even use a finderscope with my refractor.    The first thing I did when I bought the 120ED was sell the finderscope.     My widest TFOV eyepiece serves as my finderscope.  Sometimes that is the 40mm Pentax XL (2.8 deg TFOV).  Sometimes that is the 32mm plossl, 32mm Brandon or 28mm Pentax XL (1.6 deg TFOV).  Or if I’m feeling really interested in a challenge I might even use the 12mm XF or 9mm Morpheus (0.77 deg TFOV) and go sweeping for the target.    I sight along the tube to locate stars to starhop from or a lot of times I just point the OTA right to the location of the target.   I find it remarkably efficient.

    Like I said,  I can make it work..  You talk about spending more time observing the object,  working a list of double stars at 60 degree elevation with a 50 mm RACI finder is much more efficient than awkwardly sighting along the tube,  and then using a wide field eyepiece to locate the object.. 

    With my short focal length refractors,  I generally just shoot from the hip..  But there is no doubt,  the Dob  with the Telrad and RACI finder is much better for easily finding more challenging objects. 

    Jon Isaac(San Diego, California, USA) form an online thread entitled, Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

     

    Richard Whalen, on 04 Mar 2017 – 6:14 PM, said:

    Planets, brighter DSO objects or the moon in high contrast the refractor can be the best choice.

    After more than 50 years observing, I find the aesthetics of the view more important than the brightness. Also part of the experience for me is also sitting out under the stars on a perfect night and seeing the silhouette of that long white tube against the background of a sky full of stars. Somehow it’s how it should be, and all is right in my world.

    I know what you mean; there’s something about those grand old 6-inch achromats on their massive German equatorial mounts that sends a chill down the spine. The views are incredibly clean, and the scopes are big enough to yield some very detailed views of the planets — but just barely big enough.

    The fact remains that a 12-inch Dob is far cheaper and more portable than a long-focus 6-inch achromat. And while its aesthetics may be lacking, on a good night it can deliver far more planetary detail than said achromat.

    Tony Flanders(Cambridge, MA, USA), form an online thread entitled, Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    mlbex, on 17 Mar 2017 – 6:34 PM, said:

    When is the last time a major observatory built a refractor? As far as I know, the largest refractor still in use is the 36-incher on Mt Hamilton, built in the 1880s (according to Wikipedia)! It’s still a fine telescope, but there’s a reason observatories are building reflectors. Perhaps they scale better. That wouldn’t really be a problem with everyday astronomers.

    Yes, reflectors scale vastly better, for several different reasons. To be precise: false color scales linearly with aperture, large lenses are hard to support, and the glass for a lens has to be perfect throughout its thickness rather than just at the surface. And this is indeed an issue for everyday backyard astronomers.

    Refractors pretty much rule supreme in apertures smaller than 90 mm. There are some pretty good 76-mm Newtonians on the market, but they’re only marginally cheaper than equivalent reflectors, and they have a number of disadvantages. So they appeal mainly to people who are really hard-up for money. There are also a handful of Mak-Cas scopes in apertures of 60 or 70 mm, but since the main benefit of that design is small physical size, and 60- or 70-mm refractors are already quite small, the tiny Mak-Cas’s aren’t very popular.

    Refractors are also quite competitive in apertures from 90 to 125 mm. But toward the top of that range, the disadvantages of the design are beginning to kick in big-time. At 125 mm, either you end up with a short-focus achromat with tons of false color, or a long-focus achromat that’s really unwieldy and hard to mount, or an apochromat that costs a minor fortune.

    At 150 mm, refractors are really a stretch. Very few people can afford apochromats in this size, and with achromats you typically end up with both lots of false color and an unwieldy size. There are nonetheless some people who love 150-mm achromats because of their low light scatter, but that’s truly the end of the line. Refractors bigger than 150 mm (6 inches) are rare indeed in the amateur world.

    With reflective designs, by contrast, you’re just getting started at 150 mm. That’s considered quite small for a Newtonian, and not quite there for an SCT. Eight-inch Newts are really cheap and effective, especially on Dobsonian mounts, and eight inches is the standard size for SCTs.

    In the modern world of amateur astronomy, where deep-sky objects are the most popular targets, even 8 inches isn’t much. That’s barely enough to resolve most globular clusters or see the spiral arms of the biggest and brightest galaxies. So while refractors certainly have their place for viewing wide fields, for viewing the planets in less-than-perfect seeing, and above all for photography, the fact that they scale up poorly definitely limits their popularity among amateur astronomers.

    Tony Flanders(Cambridge, MA, USA), form an online thread entitled, Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    Newtonians, provide a natural, simple viewing position for the eyepiece at all apertures. Refractors and Cassegrains require tall tripods and star diagonals. We’re not going to make the artificial distinction and comparison between 90mm refractors and 90mm reflectors or between any other refractors and reflectors that happen to have nominally matching apertures.

    Caveman_Astronomer, from an online thread entitled; Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    Redbetter, on 20 Mar 2017 – 10:30 AM, said:

     

    caveman_astronomer, on 18 Mar 2017 – 1:17 PM, said:

     

    Newtonians, provide a natural, simple viewing position for the eyepiece at all apertures.

     

    An equatorial Newtonian appears to have some rather unnatural eyepiece positions depending on the declination of the target and the position on relative to the meridian.

    No, I’d say that if an equatorial-mounted Newt has rotating rings, it’s always easy to find some comfortable viewing position regardless of where the scope is pointing.

    However, I don’t really agree that Newts provide the best viewing position regardless of aperture. I do agree that alt-az mounted Newts (including Dobs) have the best ergonomics of all designs up to a focal length of around 1,500 mm, maybe even to 2,000 mm. But beyond that, they start to require increasingly tall ladders, which begin to get genuinely dangerous and/or scary around 3,000 mm. In those focal lengths, I think that Cassegrain designs are quite clearly superior, due to the fact that you’re observing from the bottom of the tube and the fulcrum is closer to the back than the front.

    Refractors certainly have the worst ergonomics, at least in focal lengths above 1,000 mm. They really have the worst of all possible worlds: bottom viewing, long tube, fulcrum far from the eyepiece, viewing angle exacerbates variation in head height rather than counteracting it as with a Newtonian.

    Tony Flanders(Cambridge, MA, USA), form an online thread entitled, Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    I’ve just recently got myself my first refractor (a 120mm f5 achro) after having used an 8″ f6 dob my whole life. I was actually quite surprised to find the ergonomics much worse and I have had to constantly adjust the height of the tripod to find a good position. Despite this, observing close to the horizon for long periods of time seems quite awkward for the neck.

    Olle Erikkson(Sweden), form an online thread entitled, Why are refractors considered to be sharper than reflectors if resolution is a function of the aperture?

    300x in an 8 inch is a 0.7 mm exit pupil or about 37.5x /inch. Even my 70 year old eyes can view the planets at magnification levels and more, provided the seeing supports it.

    I consider 300 x fine for an 8 inch..

    Jon Isaac(San Diego, California, USA),from an online thread entitled, 8″ F/5 Newt planetary and coma

     

     

    Richard Whalen, on 09 Jul 2019 – 04:34 AM, said:

    How much magnification you can use depends on your optical quality, seeing and your eyesight and aperture. With my 8″ scope I am often around 350x to 450x on Jupiter, and 525x on Saturn. Sometimes higher when conditions are perfect.

     

    My rule of thumb is 43x the aperture in inches on a very good night with decent optics, higher for very good or excellent optics. Also much depends on which planet you are observing.

    Richard, I am usually between 333x and 400x on Jupiter in my 8″, as well, at 0.6mm and 0.5mm exit pupil. I find 333x (~40x per inch) power to be the most productive and my rule of thumb, as well. At 400x, Jupiter is still workable, but it’s beginning to dim a little. I was looking at Oval BA the other night, it was easy at 333x. I could see it at 400x, but not as easily.  And I am fairly sure at 500x it would have been even more difficult. I accidentally pulled out the wrong eyepiece and hit 1200x once (0.16mm exit pupil!). Not much to see up that high. I guess my optics are not that good. smile.gif

    I get that the quality of our optics produce nice sharp and high contrast images at high power, after all it’s the same quality image we see at less magnification where (lack of) aberration is apparent in terms of resolution and contrast. But I am always interested in the mechanism of how high quality optics can afford higher magnifications at vanishingly small exit pupils, say a bit smaller than 0.5mm, without excessive image dimming. At some point we begin to lose visual sensitivity and, thus, lose the image itself as the eye is working at a very small relative aperture (less than about 0.5mm f/60).

    Getting closer to 600x on Jupiter, IME, is unworkable (or at least not as productive as a bit less magnification) in any 8″ aperture even in good seeing. I mean, we can still see some detail up that high, I saw some detail at 1200x, too. Just not much detail was perceived by the eye, even though we are viewing the same fine afocal image we observed at 400x and less. At some point, it becomes less about the optics and more about the exit pupil and, I suspect, throughput as well.

    For example, Jove is fine on both 6″ Mak and 8″ Newt at 0.6mm exit pupil, (240x and 333x, respectively). But, at 0.5mm exit pupil, the Mak image is unworkable while the Newt image still had some legs. I suspect this has something to do with the throughput of each scope, not so much about their respective quality or difference in aperture. Of course the 8″ image is brighter, thus affording higher magnification than the 6″. They are pretty close to the same level of quality, not premium but pretty good and roughly the same obstruction. Both were thermally stable and well collimated. Seeing varied from above average to very good in both over time.  (I agree with you in another thread when you talked about stray light control and mechanics, too.) 

    But, when I hear folks talk about quality optics affording higher magnification, I am always reminded of the small exit pupil involved and how quality might over come the inverse square law and our own personal level of acuity (as a variable). Unless you or they mean magnification higher than say 1mm exit pupil when poor optics start to become visually and visibly soft, while better optics retain their fine imaging properties until the image surface brightness is no longer supported at smaller exit pupils. Sometimes when folks talk about ludicrous magnification in any scope, and especially in premium scopes, I wish they’d elaborate on what they saw up that high. Tight double stars or a bright planetary nebula? 

    I just do not understand how quality affords higher magnification to smaller than 0.5mm exit pupils (very small relative apertures) and well above the magnification where poor image quality becomes apparent. 

    Asbytec(Pampanga, Philippines), from an online thread entitled, 8″ F/5 Newt planetary and coma

    After 500x the image starts to get too dim in a 8″. This is where a 14.5″ shows it’s stuff at 1000x on Jupiter.

    Chas, I know you have great seeing. My seeing is pretty much the same during our dry season monsoon. So, yea, we’re operating at higher magnifications, generally, and on Jupiter, specifically, as well as other objects. I guess that is the crux of my question. Assuming descent optics in both, the 14.5′ at 1000x is about the same as an 8″ near 550x. In my experience with an 8″, the image is less productive starting about 400x and above. Others may vary somewhat, of course.

    Unless the optics are truly better in the 14.5″ in appropriately good seeing. Then my question is why can the higher quality, larger 14.5″ aperture show it’s stuff at much higher magnification than roughly the equivelent of an 8″ showing it’s stuff at 400x? The equivelent magnification in the 14.5″ would be about 750x, but why does quality allow it to show it’s stuff at 1000x (equivelent of 550x in the 8″)? I’d love to know what can be seen up that high because, my thoughts are, the 14.5″ image is dimming, too, for the same reason the 8″ is already dimming at 400x and higher.

    I’ve seen the Jovian image at 500x and 600x in the 8″, but I would not call it really a great image (on the eye, anyway). There is some detail to be seen, still, and the limb appears to be as sharp. But, a lot of the lower contrast detail is becoming or is already difficult to see. Bright high contrast stuff like double stars are no problem, but Jove is a different animal. It cannot be pushed to ludicrous magnifications, but if it can and optics are the reason, then my question is why and what is seen up that high. A sharp limb, a few belts, the moons, and maybe the GRS?

    Asbytec(Pampanga, Philippines), from an online thread entitled, 8″ F/5 Newt planetary and coma

    My lifetime-best view of Jupiter in the 12.5″ was at 456x (36.5x/inch), and we could see a knotty white swirl in the salmon colored (then, now it’s more orange) GRS.

    The whole disc looked like the surface of an orb, not a flat disc, and the colors were amazing–ochers, pale ivory, bluish tints, grey-greens, reds, whites, blacks, greys, etc.

    It was a technicolor image, and super-sharp–sharp enough we could see the shadows of projections on the cloud banks below. And an 18 element stack of lenses in the focuser.

    Spectacular seeing conditions, obviously.

    On other nights of superb seeing, I’ve gone as high as 986x (79x/inch), just to see if it could be done, but I haven’t been able to see what I saw that night.

    The moral of the story is that it is not only optical quality, but seeing that determines how high a magnification we can use.

    In absolutely perfect seeing, I’ve used a superb 7″ scope at 160x/inch and the image was OK. I just couldn’t see anything in that scope at 160x/inch

    that I couldn’t also see at 100x/inch, though the image of Saturn at 1123x was incredibly large.

    But even after all the crazy high powers, give me 400-500x with spectacular seeing, and I can see details on Ganymede and Neptune. 1000x isn’t really necessary.

    It’s all about the seeing.

    Starman1(Los Angeles, California, USA), from an online thread entitled, 8″ F/5 Newt planetary and coma

     

    The short answer is that a good Premium telescope will probably perform noticeably better than an average cheap mass-marketed one. Somewhere between better and way better. But that’s actually a statistical statement. Occasionally a too-good-performing cheap one somehow slips through their QC system… and occasionally a Premium scope will be deficient. The Premium scope is almost always worth the Premium price differential. That is to say — if you don’t want to mess around — just buy the better scope and enjoy it! 

    Tom Dey(Springwater, New York, USA), from an online thread entitled: Premium 1/10PV 8″ Newtonian vs mass market 8″ Newtonian.

    I owned a Synta 8”f6 Dob along with a custom 8”f6 Dob with a Zambuto mirror for several years. The differences in the views were subtle, requiring side-by-side viewing on rare nights of excellent seeing to confirm. On the other hand, the improvements in the views offered by two inches additional inches of inexpensive aperture were obvious.

    If an 8” scope is the largest you want to handle, and you want improved views, premium 8” optics will provide a marginal improvement at about 10x the cost. An inexpensive 10” scope will cost about 2x and the improvements in its views will be obvious. However, premium scopes usually come with premium mechanics in addition to premium optics, and the mechanical improvements are usually obvious under all circumstances.

    So, my preferred approach these days is to empirically determine the largest scope that I am comfortable using at an observing site, and then upgrade or replace its optics and mechanics as much as my budget allows

    Gwlee, from an online thread entitled: Premium 1/10PV 8″ Newtonian vs mass market 8″ Newtonian.

    Make sure that “1/10 wave Peak-to-Valley” rating is on the wavefront, not the mirror surface. Also, make sure the seller has a good reputation.

    I went a different route, and had my first Synta 8″ F/6 mirror re-ground by a respected glass-pusher, as its initial figure was quite poor. To fill in the gap while this was in process, I purchased a second Synta 8″ F/6 (yeah, seems like a stupid idea, but the second one was reasonably good). The total cost was lower than buying a complete specialist-built scope, but of course I had to do a little work myself.

    I’ve decided to hold onto both scopes for now. I’ve set up the one with the great mirror using a better mirror cell, low-profile focuser, and smaller secondary, optimizing it for high magnifications, while the second scope is for lower mags, with a larger fully-illuminated field.

    Like you, an 8″ Newtonian is at my limit for weight and size.

    Hoawardcano(Olathe, Kansas, USA), from an online thread entitled: Premium 1/10PV 8″ Newtonian vs mass market 8″ Newtonian.

    Starlease, on 19 Jul 2019 – 7:44 PM, said:

    Put a Zambuto mirror in my 10″ dob and it outperformed my 14″ claimed 1/8 wave dob for planetary details seen. Little tiny details on Mars seen in 10″ were invisible in 14″.

    Your 14″ dob at 1/8 wave is about 1/4 wave at the wavefront – just diffraction limited. It’s possible in extremely good seeing that your 10″ would show more detail, but on an average night I doubt it, unless there are other issues that you haven’t thought about like cooldown, collimation, mounting of optical components, or maybe the claim of diffraction limited of the 14″ isn’t true.

    People are always looking for fairy dust they can sprinkle into their telescopes to make them defy the laws of physics. Someone let me know if it works. smile.gif

    Nirvanix(Medicine Hat, Alberta, Canada), from an online thread entitled: Premium 1/10PV 8″ Newtonian vs mass market 8″ Newtonian.

    Replacing the 2ndry will probably be the best bet

    but you should learn how to star test 

    https://youtu.be/QxUQJjjsdW4

    Pinbout(Montclair, New Jersey, USA), from an online thread entitled: Premium 1/10PV 8″ Newtonian vs mass market 8″ Newtonian.

    Although I didn’t do it with 8″, but with 10″, I think the mirror exchange was a large improvement for visual observations. Views through my GSO 10″ were good, but star tests have shown some astigmatism. Following the advice on this forum, I exchanged the secondary mirror for Antares, but the astigmatism was still there. So, I decided to exchange the primary for the 1/10 pv. The difference is considerable. With GSO mirror, the views were very good, now they are great. I can see many more crispy details on Jupiter, Saturn, Mars or the Moon. Things that were ‘soft’ before are sharper now. And it happens even on the nights with poorer seeing, I just have to wait for the moment in between smile.gif

    For low-power, wide-field DS objects, probably there is no difference, but color: GSO coating produced a greenish touch, OOUK makes it more white/ flat.

    With GSO mirror, I often used the aperture mask to see planets sharper. After exchange, in my opinion the aperture mask only makes things dimmer and less sharp, so I guess the scatter light before was bigger with the standard mirror. 

    Overall, I have learnt the lesson saying that the exchange for a better mirror was worth it, the telescope is used now more often for the sheer joy of visual hunt for details.

    WOJ2007(Tychy, Poland), from an online thread entitled: Premium 1/10PV 8″ Newtonian vs mass market 8″ Newtonian.

    After owning a really fine 8” CZ mirror for several years I am always impressed by the views when the mirrors are properly collimated and when the primary mirror has reached thermal equilibrium. Is it better than a mass market 8”? I can’t say because I have no way to compare. It’s also really light for the given aperture (better construction/thinner mirror) without giving up stability.

    What I can say about my premium reflector is that the mechanicals beat the pants off my venerable, but flawed 10”. The focuser, balance, bearing smoothness, primary mirror cell, secondary mirror holder are superior in every way. The entire tube is flocked and the cradle design allows the tube to be easily turned and/or moved north south. My definition of a premium scope (which includes the mirror) is one that both offers expected mirror performance while the structure disappears as one uses it. A premium scope is more than a premium mirror and a premium mirror will fall short of full potential if one has to battle with the other parts.

    Chesterguy(Stillwater, Oklahoma, USA) from an online thread entitled: Premium 1/10PV 8″ Newtonian vs mass market 8″ Newtonian.

    I have two 8ers to compare, one Zambuto 8″ F7, the other a generic “Skywatcher” 8″ F6.

    But the comparison is necessarily through memory . . .

    I visit family a couple of times per year in Australia. Got tired of lugging my C6 and refractor through airports. So last time back I bought an 8″ F6 “Saxon”, which is the same as the Skywatcher 8″ solid tube.

    About a year ago I came across an ad where a guy had the parts for an 8″ F7–the primary being a Zambuto quartz, and the secondary a 1/30 wave Antares. Moonlight single-speed focuser. A solid tube (flocked), and splashed out for an Aurora precision cell. I run it alt-az on a Skytee 2 mount.

    How do they compare?

    I wasn’t expecting miracles with the Saxon. A solid diffraction limited scope was all I was wanting.

    First object was Sirius at high elevation in quite good seeing. Within 2 minutes of setting up the scope on first light I easily split the pup. Done. This is a good scope!

    Star test isn’t perfect (I am no expert on this). My recollection was a brighter ring on the outside on one side or the other of focus. So I’m guessing a less than perfect edge. But it performs very well indeed, and more than met my hopes. I haven’t spend much time on planets with this scope (it does perfectly fine). When down under I’m more interested in the Southern objects–Magellanic clouds put up a ton of detail in this scope.

    But what about that Zambuto? Well, as far as I can tell it is as close to perfect as you can get in an 8″ mirror. Star test looks identical to my eye on either side of focus.

    The mirror is up and ready to go with just a couple minutes of running a fan, and puts up etched views of the planets and moon (it has a very small secondary, and is optimized for planets). A particularly memorable view was of the double double from Mt Pinos (parking lot must be close to 8k ft). Perfect dots and diffraction rings. An observing friend with a lot of experience called it the best view of the double double he’d ever seen.

    But how would this thing compare to a 10″. Well, I think you’ll get a more sharp/contrasty view out of the 8″ premium, but so long as the 10″ is decent, it will resolve more detail, those details will just look a tad softer.

    Areyoukiddingme, from an online thread entitled: Premium 1/10PV 8″ Newtonian vs mass market 8″ Newtonian.

    N3p, on 19 Jul 2019 – 5:57 PM, said:

    Has anyone replaced their regular 8″ Synta Newtonian with a higher quality 8″ Newtonian and how was your experience?

    The key difference I found was as follows.    During critical observation of an object for 5-10 mins, on the couple of times when the atmospheric seeing snapped into focus- lasting 0.5 to 2 seconds- the mass market mirror would give an “ooh nice” response whereas the premium would give a “wow!” response.

    The rest of the time the mirrors were pretty similar.

    On galaxies, the higher strehl mirror gave just enough contrast to pass a threshold where the eye could suddenly detect a dust lane.   The mass market mirror couldn’t reach that threshold.

    Max T, from an online thread entitled, Premium 1/10PV 8″ Newtonian vs mass market 8″ Newtonian.

     

    An inspiring 6″ f/8 ATM build by Matthew Paul, Orange County, New York, USA

    Though I did not  build the scope for imaging, I wanted to share what it is capable of under not so ideal conditions. Very happy with the results of the optics. I need to build a better OTA for it. It’s rather flimsy, the spider is not rigid, the tube flexes, and the focuser is just a plastic rack and pinion, but it works very well for now, and the hard part (the optics) are done. Thank you again to everyone that offered information and assistance as I worked on the mirror.

    MVI_0140-3.jpg

    Matthew Paul(Orange County, New York, USA) quoted here

    Matthew Paul, on 22 Jul 2019 – 3:32 PM, said:

    Though I did not  build the scope for imaging, I wanted to share what it is capable of under not so ideal conditions. Very happy with the results of the optics. I need to build a better OTA for it. It’s rather flimsy, the spider is not rigid, the tube flexes, and the focuser is just a plastic rack and pinion, but it works very well for now, and the hard part (the optics) are done. Thank you again to everyone that offered information and assistance as I worked on the mirror.

    attachicon.gif MVI_0140-3.jpg

    That image ought to give apo owners pause.

    Ed Turco(Lincoln, Rhode Island, USA), from the same thread

    There is real poetic justice in how well a good Newtonian telescope performs.

    JamesMStephens(Hattiesburg, Mississippi, USA), from the same thread.

     

    Hello Marty, I can’t answer all your questions, but I did a shoot out between a 150mm f/8 achor and 200mm f/6 dob on Mars a few years ago at opposition.

    The Dob was much better, I suspect it had more to do with no CA vs the increase in aperture. Mars was smeared with false color rendering very little detail in the views. I sold the Achro because it was too much for me to mount. And in my light polluted sky, I don’t do much low power deep sky.

    I suspect that It would also lose fine detail on Jupiter, but I could not do a side by side compare.

    I have a 6 inch 150 f/5 newt, and it does a good job on Juipter/Saturn. I have not had a shoot out between it and say a 100mm ED, or 120 8.3 acrho for a comparison. As far as personal tastes, my eyes are getting old and are light starved, so usually a brighter less crisp image is preferred over a dimmer crisper one.

    I suspect …. the best scope for viewing the planets at 150mm without going crazy expensive would be the 150 f/8 dob. I’m looking for one right now in the used market. A 120 ed I suspect would do a good job too, but at 4x the price, and a big mount to boot.

    I have an f/5 250 reflector on a dob mount. Best view of Jupiter I have. It does take an hour to cool.

    Vtornado( Northern Illinois, USA), from an online thread entitled: 150mm Instrument for Planets, Which Type?

    I’ve tried them all over the past 40 years.  Best view of planets was through Newts with good mirrors that were properly collimated. Note the underline, because that (particularly the latter) can be an issue with Newts. For something more compact and lightweight a good 6″ Mak is an excellent planetary scope and it won’t cost you an arm and leg.  I just picked up a used Orion 150 Mak and the (visual) images of Jupiter and Saturn are superb. My old 127 Mak is also good but the 150 gives more edge on brightness.

    fcathell(Tucson, Arizona, USA), from an online thread entitled: 150mm Instrument for Planets, Which Type?

    I think a 6” f/8 dob, with top notch optics

    (Spooner) would be a great choice and affordable.

    NHRob, from an online thread entitled: 150mm Instrument for Planets, Which Type?

    6″ mak

    6″ f/8 newt

    4″ fpl-53 double Vixen or triple

    will all give great planet views.

    tomjones, from an online thread entitled: 150mm Instrument for Planets, Which Type?

    tomjones, on 23 Aug 2019 – 01:02 AM, said:

    6″ mak

    6″ f/8 newt

    4″ fpl-53 double Vixen or triple

    will all give great planet views.

    Why add a 4″ into this discussion when it’s an inferior option?  A good 6″ f8 outdoes it.

    azure1961p, from an online thread entitled: 150mm Instrument for Planets, Which Type?

    MalVeauX, on 23 Aug 2019 – 6:33 PM, said:

    So… to add more to this mix…

     

    What would any experienced observers rate a 200mm F6 Quartz reflector to a 150mm F8 ED doublet for planetary views?

     

    Would the extra aperture make enough of a difference?
    Or would the 150mm F8 ED refractor still throw up the better, higher contrast image?

     

    Very best,

    The extra aperture would make enough of a difference if the mirror were superb, the tube material, thermal issues, focuser etc., were all finely tuned and working together. Then there are the ergonomics of viewing position and the question of what type of mount will be used.

    If one were to buy a used 8″ f/6 “classic” EQ mounted Newtonian from a good source, such as someone here on CN, then that would be a very efficient bang for the buck. Especially if the mirror were a known and proven winner. Probably in the Approximately $500 range vs. $2000 for the 150mm f/8 ED.

    “Would the 150mm F8 ED refractor still throw up the better, higher contrast image?” Yes it could, if the 8″ f/6 newt had degraded mirror coating and dust, not collimated perfectly, focuser not smooth, set up on warm surface so that thermals enter the tube and plague the system etc., But in my opinion the Newtonian will win if the details are all taken care of and watched. 

    I wish I could find a local old classic 8″ F/6 EQ mounted Newt to play around with, actually…

    Everlasting Sky( Vancouver, Canada), from an online thread entitled: 150mm Instrument for Planets, Which Type?

    I concur with fcathell, as far as planetary observing with Newtonians when all the necessary conditions are in play. My very best planetary views have been through large truss-tube Dobsonians with premium mirrors, along with large classical Cassegrains, when the seeing has been excellent.

    I also agree with Richard Whalen’s post when the aperture is limited to 6 inches.

    Dave Mitsky(PA, USA), from an online thread entitled: 150mm Instrument for Planets, Which Type?

    Quote

    Even with spot on collimation (Newts, DOBs, Maks, SCT’s, etc.) – you still have a central obstruction vs. none in a refractor and that reduces contrast and resolution…even if just slightly — it does

    It’s worth keeping in mind that the CO does have a small effect on contrast, not on resolution..

    This does mean that a scope without an obstruction, when compared to an other equivalent scope of equal aperture will have reduced fine scale contrast.

    But that’s only if the apertures are identical and the optical quality similar. Otherwise, the contrast is affected by the aperture far more than by a central obstruction. This is why large scopes with COs can provide much greater contrast than a scope without a CO.

    Some years ago I experimented with my 120 Eon by adding a 40% CO, I could see a loss of contrast but it was surprisingly small.

    In this comparison, unless one went with a high quality Newtonians (Spooner) then a $2500 ED Doublet would likely provide better planetary views.

    On the other hand, if weight and length were the guidelines, the a good 8 inch Newt would be hard to beat.

    Jon Isaac( San Diego, California, USA), from an online thread entitled: 150mm Instrument for Planets, Which Type?

    M11Mike, on 24 Aug 2019 – 01:12 AM, said:

    Jon – normally I’m with you 99.9%.  But I have seen numerous times FIRST HAND where a quality 4″ refractor beat out much larger apertures on the planets.  And I don’t think the guys with these scopes didn’t have them properly collimated, etc.  These guys with scopes (like the Meade 10″ SCT) were my observing buddies and they concurred.   They were active seasoned observers like myself.

     

    Mike

     

    Well.. maybe. But you can’t blame that on the CO.  Thermal issues, optical issues, poor seeing..

    Try adding a 35% CO to a 4 inch Refractor and see how much difference it makes.

    Jon Isaac( San Diego, California, USA), from an online thread entitled: 150mm Instrument for Planets, Which Type?

    I’ve had a 6″ F8 newt with 1/8 wave optics and it was excellent for L&P. I’ve got a IM715D mak and the same can be said of it. Big advantage to the mak is in 8 years I’ve never had to collimate it. Either scope would work on my Twilight 2 without a counterweight, I doubt the same could be said of a 6″ refractor. I’ve got an excellent WO ZS110 triplet and it doesn’t outperform my mak or C9.25XLT for L&P unless seeings sub par.

    dscarpa(San Diego, California, USA), from an online thread entitled: 150mm Instrument for Planets, Which Type?

    First Light Report
    Finally, the time had come for first light.  When I put the Glatter laser collimator into the focuser and turned it on to begin aligning the optics, I was stunned to see that the laser beam was hitting the primary mirror inside the circle in the middle of the hotspot.  Despite being driven over 1000 miles and loaded/unloaded twice, the tolerances are tight enough on the telescope. I’ve setup the telescope four different times since – and the initial laser position on the mirror has been inside the 1/4″ (6 mm) hole at the center of the HotSpot every time.  Collimation required less than 1/16 of revolution of any of the knobs on either the secondary or primary mirrors.  I pointed the telescope at the horizon and the zenith.  I moved quickly in altitude and azimuth, and slid the EQ platform through it’s entire range of motion twice.  Collimation didn’t shift.  At all.  
     
    Once the sun dove behind the hills just to the west of the observing site, I uncovered the optics and started the fan in earnest to get the optics cooled to ambient as quickly as possible.  I carry a 10″ rechargeable fan that I used to push air at the front side of the primary mirror, and allowed the built in fan to pull air across the back.  The mirror box is only about 8″ deep in total, so air is able to flow easily around the optics and through the structure to help with temperature changes and cooling. Once full darkness had descended up on the observing site, I removed the front fan, rechecked collimation and got to the business of deep sky observing with the new telescope.  I left the rear fan running at full speed, where it’s just audible as a background noise.  Later I turned this down some just to quiet the fan in the silent nighttime desert. Temperatures dropped 23º F (12º C) over the next 2 hours. The thin optics and open structure of the observing rig did a wonderful job of keeping up with the change.  
     
    When I first began talking with Mike Lockwood about commissioning a fast, thin mirror he told me that I’d likely never seen what a cooled telescope could really do being that my main observing machine has been a 15″ full thickness OMI mirror in a wooden Obsession structure.  I love that telescope, but I learned on this weekend what Mike was talking about.  Conditions that had been blamed for years on poor seeing were not present on this night, even though we all agreed that the seeing wasn’t any better or worse than a typical night at this location.  I spent nearly all of my time over the next few nights observing comfortably with much higher magnifications than I’d ever been able to use previously. 
     
    NGC 5139 – Even though it culminates at just 11º above our southern horizon, Omega Centauri was on the meridian at the end of astronomical twilight, so the three of us agreed that it was the obvious choice for the first target.  We’re all familiar with the views of this object from this site with instruments of all sizes from a 63mm Zeiss refractor to a 20″ f/5 Obsession.  At this low elevation there were some obvious atmospheric artifacts being induced in the image – but we all agreed that this was the finest view we’d had of this granddaddy of globulars.  With a 21mm Ethos I immediately noticed a couple of things.  1 – The telescope maintained perfect balance though it was pointed 10º above the horizon.  When I removed the eyepiece to switch to a lighter one, the telescope didn’t budge.  I’m no designer, but I attribute this to the use of the 30″ altitude bearings and perfectly balanced design.  2 – I was looking at Omega Centauri with 20″ of aperture and a 1.2º true field of view.  The cluster was lost in the middle of a field with all kinds of black space around it. With all that aperture focusing all that globular into the smaller image scale of this wide field, the cluster was astonishingly bright, even by it’s elevated standards.  I hadn’t changed eyepieces or objects yet, and I already knew…..this was going to be a fun telescope.  At 175x in a 10mm Ethos, the cluster is huge, extending nearly to the edges of the field.  What I noticed most was the stars being impossibly tight pinpoints, with black space around them.  The contrast between the globular’s stars and the background sky is the most notable thing from the observation.  
     
    NGC 5128 – This beauty in Centaurus is so close by that you can’t *not* look at it.  Again, the contrast was the most noticeable thing about the observation.  With the 10mm Ethos, the dust lane is sharp and well defined across the face of the galaxy and appears nearly bi-sected with a brighter middle – like looking at the great rift from millions of light years away.  
     
    I wiled away a few hours working through the Virgo cluster high in the west, spent some time counting galaxies in the Coma cluster and then happened upon what has been the most memorable view through this telescope yet.  
     
    M83 – Again, it was the contrast.  An absolute pinpoint of a nucleus with two sharply defined bars extending away for a few arc minutes and then turning sharply to form those beautiful, elegant spiral arms.  What struck me most though was the dark lanes between the arms.  As I continued observing, differences in darkness began to appear in the dark lanes, as well as brighter spots in the spiral arms (HII, OB assocations?).  I didn’t concern myself too much, I just enjoyed the view.  This telescope rocketed this galaxy to a high place on my favorite objects list.  
     
    M57 – I put the telescope on this old standby and basically went camping at the eyepiece.  With an 8mm Ethos, the central star was just there.  It didn’t jump out at you….but it was there and required no effort beyond basic averted vision to see it clearly.  I noted galaxy IC 1296 nearby and that it too was pretty easily seen.  This was where I pushed the magnification.  With a 3.7mm Ethos, the telescope is operating at 475x magnification.  In moments where the seeing settled and the air was steady, the optics weren’t even breaking a sweat.  I was able to observe 4 stars seemingly involved with the nebulosity and the central star was a direct vision object at this magnification.  The interior surfaces of the nebula were clearly mottled and uneven and the entire nebula appeard electric green in the eyepiece.  
     
    Veil Nebula – Always a favorite, our small group spent a solid hour cruising the wisps of this supernova remnant with the telescope.  With an 8mm Ethos and an O-III filter, the nebulosity glows as if backlit by some artificial LED source in the eyepiece.  I traced the entire outline of the nebula noting how the brighter wisps faded into thinner and fainter ones as I followed until they just seemed to disappear.  There’s a patchwork background of nebulosity that I hadn’t noticed before with my 15″ scope.  

    48370580567_bd2a867e80_c.jpg
    Great friend and fellow observer Alan Strauss told me I needed to remain still while observing M101.  Uhhhhh….okay!  That won’t be hard.  I could sit here all night.  
     
    …and then came the planets.  I have listened to Mike Lockwood bang the drum about planetary observing with big aperture mirrors for quite awhile now.  Like I told him afterward, consider me one of the converted.  Jupiter at any magnification was an absolute razor blade of sharpness.  Where I was used to seeing equatorial bands, I was now greeted with a swirling mess of sharply defined festoons and bands within bands.  Viewing Jupiter this night was the best views I’ve had that I can ever remember.  My friend Alan commented a few weeks later that the thing that stood out most to him was how sharp the planetary views were through this 20″ scope – he wasn’t expecting it to perform the way that it did.  I concur.  
     
    Just a couple of weeks ago, I set the telescope up again in my light polluted Phoenix backyard to give a quick view of the moon and Jupiter to my lady.  I’ve not been much of a lunar observer since I was a kid, but she is in love with the moon….so, it was time to show her the moon through the new telescope.  She’s not an astronomer by any means….and she’ll be the first to tell you that she doesn’t have those aspirations.  I was stupefied when I looked in the eyepiece.  Stop me if you’ve heard this before – the contrast is unbelievable  – and not just the inky blackness of the crater shadows and brightness of sunlit portions of the lunar surface.  The subtle variations in illumination in the mare and even light differences in color were obvious and a pleasure to behold.  What was supposed to be a quick 20 minute show of the moon and Jupiter turned in to a 2.5 hour session together.  We spent the longest time comparing notes and pointing out features and seeing the smallest details.  The experience has converted me into someone who’s ready to look at the moon again.  I look forward to the intersection of my travel schedule with a break in the Arizona monsoon and a favorable location of the moon so I can repeat the experience.  
     
    Conclusion
    I wanted big aperture with no ladder and absolutely no compromises on the optical and structural quality of the telescope.  It came with an uncompromising price tag too – but I couldn’t be happier with the combination of the Lockwood optics and Osypowski structure & platform.  Mike Lockwood’s reputation for ridiculously fast, sharp optics is well deserved and I’d even dare say still underappreciated.  I selected Mike as my optician for a couple of reasons.  1 – He was great to talk too and has been a great resource for all astronomy/telescope related questions since first talking with him back in December 2017.  2 – A couple of extremely experienced observers that I respect greatly both said the same thing – that the best view that they’d ever had through a telescope had Lockwood optics.  I can now say I wholeheartedly agree with their assessment. 
     
    The Spica Eyes structure built by Tom Osypowski is as nearly perfect as I think it’s possible to build at this point.  It is substantial, stiff and rigid.  It feels like it’s been built for the apocalypse when you put your hands on it.  I chose Tom because of my experience with his EQ platforms and the knowledge that he’s built several telescopes that were both larger *and* faster than this project – so I was confident i would get a telescope that matched my excitement for the EQ platform.  I haven’t been disappointed.  Twice now I’ve done business with Tom.  Both transactions rank as the smoothest, most pleasant money I’ve spent in this pursuit in my lifetime.  I’m proud to be able to say I own one of his telescopes.  
     
    Is the telescope truly perfect?  No.  I have two minor quibbles.

    • There is some stiction in the azimuth axis.  It’s not paralyzing, but it is there.  I got after it when I got back home with some car wax and a buffing cloth which has improved it.  Part of this issue is comparing it to the buttery smooth goodness that is the motion of an Obsession.  I’ve been spoiled by 18 years of use with my 15″ Classic.  
    • The light shroud fits really, really tight.  Getting it pulled down over the structure is a bit of a process.  By process, I mean it takes a couple of minutes.  Once it’s in place – it stays in place and does a wonderful job of blocking stray light but still allowing airflow through it.  So I’ll count my blessings that these are my issues with the telescope.

    I realize it’s been long winded, but there’s little information out there about Spica Eyes scopes.  In fact, there’s really not much beyond a different CN thread that was posted a few years ago about a 24″ scope Tom built.  I submit this review and future experiences and observing reports as part of that body of knowledge.  Tom Osypowski tends to fly under the radar when discussing premium telescope builders, but his handiwork is among the absolute best out there.  He and Mike Lockwood have earned every bit of credit that they get for their skills and contributions to our hobby. 
     
    Mike

    48260256751_f91f413582_c.jpg
    A great shot of the observing site in Portal, Arizona, the 20″ f/3 telescope described here, and the truck/camper that gives me shelter whilst far from civilization for long periods of time.  The light domes are greatly exaggerated in this long exposure.  The one just to the left of the truck is from Lordsburg, NM – 40 miles (64 km) away.  The light dome to the right is from El Paso, TX – 160 miles (255 km) away.

    Mike Wiles( Phoenix, Arizona, USA), from an online thread entitled, First Light Report: 20″ f/3 Spica Eyes/Lockwood Dobsonian

     

    Recently picked up a used (mint condition) Skywatcher 130mm f/5 PDS reflector OTA (Thanks Tyson). This scope is presently discontinued.

    Cosmetics: beautiful black with silver speckles. 9/10

    Inclusions: 8/10 (based on the nice focuser)

    excellent dual rate 2” Crayford focuser with 1.25” adapter

    Vixen style finder mounting shoe

    thin 4 vein spider/ adjustable 2° mirror holder

    oversized 2° mirror (this scope is designed for photography)

    Enhanced 95% coatings on 1° and 2° mirrors

    6×30 straight through finder (mine was upgraded to an Orion 8×40 straight through version)

    2” 28mm LET eyepiece (not included in my used purchase)

    Nice dual hinged mounting rings and Vixen style mounting 7” bar

    Peeves:

    Crayford focuser is non-compression ring

    Crayford focuser has a thread 2” adapter ring using a single metal set screw

    (I removed the ring and drilled/tapped 3 holes a 120° and replaced the metal set screw with 3 nylon ones). I actually prefer this type with nylon screws to a compression ring version.

    the 2”-1.25” eyepiece adapter is also thread-on. You need to unthread the 2” eyepiece adapter ring and the thread the 2”-1.25” one on. Stupid design, just include a regular 2”-1.25” – compression ring or set screw.

    You need a 2” extension tube to reach focus with either 2” or 1.25”, It is not included.

    The included 28mm 2” LET eyepiece is junk (I have tried one). Just include a 1.25” cheapo 25mm Plossl eyepiece.

    I hate straight through finder scopes, replaced mine with an Orion 6×30 RACI version (very light weight but a larger 50mm RACI maybe a better option.

    Optics: 10/10

    easily collimation (it arrived in perfect collimation), 1° mirror is center spotted

    3 spring loaded adjustment knobs with setscrew locks

    95% enhanced 1°/2° mirrors – brighter view than my larger 140mm f/3.64 Comet Catcher

    optical testing – easily 1/8 wave or better

    Observing: I am mainly a Deepsky observer – this a definite RFT

    Fantastic scope, easily punches above a 5” reflector.

    easily takes 160X + (TV 4mm DeLite) , 40x/in- you run out of light grasp

    From low power wide field (3° +) to high power, does it all.

    with high quality eyepieces, I did not need an OCS (Paracorr)

    Some Deep Sky highlights: NELM 5.7 Transparency/Seeing Both 3/5 :

    the Double Cluster – superb, one of my best views ever (mono view)

    NGC 7789 in Cassiopeia (Caroline’s Haystack) – very easy (large smudge with a sprinkling of brighter stars)

    M31 group – all 3 members are easy with direct vision – M31 over 2.25°, M110 diffuse oval

    M33 – large 3/4° smudge

    M81/82 – beautiful contrast in galaxy types

    M51 – Both parts easily visible

    M13 – easily resolved – perfect image (pin **** stars) at 160x

    M27 – amazing with and without filters

    NGC 7000 – fantastic North American shape with NPB filter

    Veil Complex – see my posting in Observing section (Veil in small scopes)

    Future Upgrades:

    I have added a 8” dew-shield

    I will flock the OTA (either the entire tube or opposite the focuser)

    Summary:

    An excellent low priced RFT. Amazing Optics.

    The few minor “peeves” are easily corrected.

    Highly Recommended !!

    vkhastro1(Ontario, Canada), from an online thread entitled, Skywatcher 130f/5PDS-mini review

    Congrats on your new scope! 

    My experience mirrors yours. It is kind of an “unknown” scope, but for my own application it is working better than the Comet Catcher in spite of being smaller and “slower.”

    This scope is kind on the stealth list because when I say I have a 130mm f/5, everyone thinks it is a typical 130mm with small illuminated field and 1.25″ focuser and most do not seem to be aware of the 130 PDS.

    vkhastro1, on 30 Aug 2019 – 5:19 PM, said:

     

    95% enhanced 1°/2° mirrors – brighter view than my larger 140mm f/3.64 Comet Catcher

    optical testing – easily 1/8 wave or better

     

    These are factors that I used in my decision to move from the Comet Catcher to the 130 PDS.  Now my situation was that I am using image intensified eyepieces and I came to feel that the Comet Catcher was punching well below the f/3.6 spec.

    Some of this I thought was maybe due to the need to re-coat the mirrors, but after a painful testing sequence, I determined that the mirrors were OK, but that they were just not transmitting a lot at longer wavelengths (which is important for NV use) and this combined with the losses of the secondary shading and the corrector (which is where perhaps 10% of the loss in near infra red is coming from) meant that the scope simply was not as bright as I thought is should be. I actually think that the entire system transmission (including secondary shading) of the Comet Catcher really does cause it to loose a lot of brightness. I came to feel that the CC was simply much dimmer than it should be for a 140mm f/3.6 scope.

    The other issue I had with the Comet Catcher was the sled focuser and the awkward nature of trying to get it to work with a filter wheel.  The 130 PDS though, with its 2″ focuser with plenty of travel made it easy to use a filter wheel.

    One important point though is that while it is an “Imaging” scope, I don’t think it will fully illuminate an APS-C size sensor.  My NV monocular has an 18mm image circle, and I can see that there is a little illumination falloff at the edge.  Not bad, but it does not appear to have a fully illuminated circle bigger than maybe 12mm. Probably good for an APS-C with some cropping maybe or a 4/3.

    Anyway, as much as I loved the light weight and simplicity of the Comet Catcher, I came to feel that it was much dimmer than the numbers suggested and moved to the 130 PDS and like you, I really feel that it is brighter than the Comet Catcher was. 

    Nice scope.   Not many around as far as I can tell though.  

    130PDS R.jpg

    (Also, the image scale was a plus.  An added bonus was that I had enough focuser travel to use the Barlow lens mounted in one of my filter wheel positions.  This Barlow gives me the ability to bump up the power by about 1.5x just by turning the filter wheel and refocusing.  That is a nice benefit.)

    Good review of what appears to be a relatively unknowns scope.  Hope you are enjoying it!

    Eddgie, from an online thread entitled, Skywatcher 130f/5PDS-mini review

    Very informative comments. I picked up one of these a few weeks ago and use it on a Skywatcher Star Discovery Go To mount that I already had. Quick to set up and cool down, great optics and works really well with my Vixen LVW eyepieces. Nothing to dislike at all.

    brisdob(Brisbane, Australia), from an online thread entitled, Skywatcher 130f/5PDS-mini review

    We are looking into this model and it’s larger models currently.

    Skyward Eyes( Skywatcher USA Vendor), from an online thread entitled, Skywatcher 130f/5PDS-mini review

    For a number of years I had a SpaceProbe 130 ST fitted with a 2 inch Focuser. I normally used it with a Paracorr.. A Paracorr would address the need for an extension tube.

    I have said this before.. a good 130 mm F/5 Newtonian is the closest thing an affordable 4 inch apo Refractor that exists… The 130ST was quite good on planets and doubles as long as it had an hour or so to cool.

    I remember one dark night.. I swapped out my TeleVue NP-101 for the 130 mm F/5  with the Paracorr and 31 mm Nagler..it was scary how good it was.. 

    4920795-SpaceProbe 130ST Starpad.jpg

    Jon Isaac(San Diego, California, USA), from an online thread entitled, Skywatcher 130f/5PDS-mini review

    Ya don’t say; I got me one of them there ‘scopes….ken. I’ve no’ got the 2″ focuser mind, but I dinnae really need it. My bestest grab ‘n’ go ‘scope ever. Eye.

    Mr. Hardglass

    I’m a massive fan of 130 f5’s, even on the ota’s that are limited to 1.25″ ep’s. Very easy to mount scopes, and, when they have decent optics, great all around performers.

    Kerry R.( Mid-west Coast, Michigan, USA), from an online thread entitled, Skywatcher 130f/5PDS-mini review

    I have been using this telescope for around 6 months now on my evolution mount as an eaa platform. For the cost, it makes an excellent alternative to my 925 for wider field views and it can reach zenith with no problems.

    Barkingsteve, from an online thread entitled, Skywatcher 130f/5PDS-mini review

    ***

    FINALLY a Dob I really enjoy.

    Been through many different sizes, ranging up to 16 inches.  For me, a 12.5″ Dob is in the goldilocks zone.  Big enough to astound me with the views, but small enough to use every clear night.

    I can’t get enough.  In just 11 weeks of ownership, I’ve used it 42 times, including several trips to dark skies (3.5 hours each way).

    Ryan built a masterpiece.  It’s wonderfully engineered & built.  The telescope is so easy to assemble & disassemble. 

    In use, it is sheer joy.  The movements are silky smooth, requiring little pressure to track an object even at 300x.

    And the views?  Just mind-blowing.  Never thought a reflector could be so sharp and have such stark contrast.  This is the first time I’ve looked through a Zambuto mirror, and the views are as close to a refractor as I’ve ever seen in a mirrored telescope.

    During the last new moon, at extremely dark skies, I pulled the old M13/NGC6207 trick on an observer.  I got her to focus on NGC6207 at 250x.  After several minutes, I asked her to nudge the scope downwards slowly.  A gasp soon followed.  Then the hooting & hollering.  I understood her enthusiasm.  M13 looked photographic.

    Ryan was very gracious throughout the build process.  He promptly & politely answered all my emails, and was very patient, despite my impatience.  He is a master of his craft, and actually converted me from a refractor guy, to someone who can enjoy the night-sky using both types of telescopes.

    Attached Thumbnails

    • CN (2).JPG

    Magnitude 7, from a thread entitled, New Moon Telescope 12.5″ Zambuto refract… er… reflector.

     

    Aperture. Obviously of a decent quality, but aperture is what reveals detail.

    Small telescopes deliver a low magnification sharp looking view, but the fine detail doesnt exist. Its sharp because the magnification is low.

    Double the aperture, double the resolution, simple as that, provided the atmosphere obliges! Which it does more often than some people would maintain.

    Happy Limpet(Southampton, UK), from an online thread entitled, What’s more important.

    If you’re going to use a reflector, mirror quality is very important. I learned this when I had my 2001ish vintage Nova mirror refigured by Mike Lockwood this year. One of the biggest differences I noted was the moon. Before, I could see features on the moon, but the smaller ones could not really be seen, or made sense of, when examined closely. It’s a hard thing to describe, but it was something I noted often, and found frustrating. Detail in the refigured mirror is much clearer in this respect, probably more refractor-like.

    If refractors give a more tightly-controlled image than a similar-quality reflector, then that would be the way to go for lunar.

    I wonder how much the resolution advantage of a large aperture reflector is lost due to diffraction, coma, viewing through a wider expanse of air and a filter, compared to a more modestly sized apo. Maybe you really need to compare apos to apos.

    Mike Tahitub, from an online thread entitled, What’s more important.

    posted 09 October 2019 – 08:16 AM

    MikeTahtib, on 09 Oct 2019 – 10:26 AM, said:

    I wonder how much the resolution advantage of a large aperture reflector is lost due to diffraction, coma, viewing through a wider expanse of air and a filter, compared to a more modestly sized apo.  Maybe you really need to compare apos to apos .

    Diffraction – essentially none.

    Coma – none if using a coma corrector, very little otherwise (depending on f ratio)

    Viewing through a wide expanse of air – none, assuming you know how to get to thermal equilibrium (clue – use fans, its easy)

    A filter? none also

    How much extra money stays in your pocket? Vast.

    Reflectors rule.

    Happy Limpet(Southampton, UK), from an online thread entitled, What’s more important.

    Jon, my experience has been thus – with my Celestron Omni 102mm f/10 (now retired), the moon looked very good, detail was good, contrast as good as could be expected for an achromatic scope, CA was well controlled, but still present. With my SW 120 ED, more detail stood out, I was beginning to see an almost 3D view of things, especially along the terminator. I could also bring the magnification up a bit more than the 102mm, but the seeing conditions had more impact. And CA? What CA?

    With my 10 inch reflector, it is an OMG experience… I had it out Monday night and it quickly reminded me why I love this scope. The detail and contrast that is visible is like being in a Lunar lander on approach… words simply can’t describe the view. The 3D appearance was eye popping. It was a decent night, not great, with the seeing like a 3/5, so at higher mags, there was a bit of waviness at times, but mostly good. Keep in mind that my 10 inch reflector is an ATM scope, so a lot of attention was put into getting top performance.

    This has just served to remind me that a good refractor is no slouch… but has some limitations. A good reflector with some aperture is magical.

    Good hunting!

    Seabee 1, from an online thread entitled, What’s more important.

    My favorite scope for lunar visual is my 8″ f/9. When seeing is good the view is tack sharp. The best view ever was with my 25″ on a extremely steady night. I was hitting 1000x and still had a sharp image.

    Like Jon, no filter.

    Keith Rivich(Cypress, Texas), from an online thread entitled, What’s more important.

     

    More on Double Stars with a  commercial 8″ f/6 Newtonian

    This report is the fifth installment of a series of observational investigations I have made using an 8 inch f/5.9 reflecting telescope.

     

    Check out this link for goals and methods used in this study:

    https://www.cloudyni…-and-monoceros/

    Corona Borealis
    COU 610 Theta (15329+3122) mags 4.27/6.29; pa = 199°; sep = 0.85“, (orbital estimate for 2019.3 is a better fit with historical 4th Int. Cat. data vs last precise from 2016)
    345x, 460x:  single star
    627x:  brightening of diffraction ring that resolves to small dot that is just split 20% of time; at resolution limit and very challenging; re-measure of separation desired

    Draco
    HU 149 (15246+5413) mags 7.48/7.62; pa = 270°; sep = 0.665“, (2016, last precise; solid data)
    345x:  moves past elongated to notched (snowman) 30% of time
    460x:  at resolved/split border as seeing allows; both stars are light yellow-orange
    627x:  resolution aided with orange filter under excellent seeing conditions; a bit above resolution limit

    Image below is from 2017.444

    STF 2054AB (16238+6142) mags 6.15/7.09; pa = 351°; sep = 0.943“, (2017, last precise; solid data)
    345x:  easily seen as split 100% of time to two white stars of slightly dissimilar magnitude; above resolution limit
    image below is from 2019.455

     

    STF 2218 (17403+6341) mags 7.08/8.37; pa = 308°; sep = 1.476“, (2015.5, Gaia DR2; solid data)
    345x:  split 100% of time to two whitish stars; averted vision aids visualization of the fainter secondary; above limit

    STF 2403 (18443+6103) mags 6.25/8.35; pa = 278°; sep = 1.061“,  (last precise, 2011; solid data)
    345x:  seen as just split 50% of the time; both stars are yellow with the much smaller secondary sitting a bit past the first diffraction ring; above resolution limit
    There may be a number of observations for this one as it is part of the Sissy Haas Uneven Double Project

    STT 369 (19071+7204) mags 7.82/7.91; pa = 8°; sep = 0.684“, (2015.5, Gaia DR2; solid data)
    345x:  just split when seeing allows; both stars are yellowish-orange with secondary a bit smaller
    460x:  easier to see as split; above resolution limit

    MLR 12 (18293+8235) mags 8.90/9.12; pa = 222°; sep = 0.689“, (2008, last precise; data is old)
    345x/averted vision:  mostly pointy
    460x/averted vision:  much smaller secondary seen as resolved only 20% of the time—very difficult; right at resolution limit; separation re-measure needed

    STT 312AB Eta (16240+6131) mags 2.80/8.20; pa = 143°; sep = 4.676“,  (2015.5, Gaia DR2; solid data)
    345x:  secondary is a tiny speck of light well separated from the primary; held steadily in view on nights of better seeing; above resolution limit

    Hercules
    COU 107 (16169+1948) mags 9.02/9.61; pa = 113°; sep = 0.609“, (2009, speckle; data is old, scant)
    345x:  very faint; merely a bit elongated; below resolution limit; important data point to assess faintness factor; re-measure of separation needed

    STF 2107AB (16518+2840) mags 6.90/8.50; pa = 107°; sep = 1.443“,  (2015.5, Gaia DR2; solid data)
    345x:  easily split; both stars are whitish and the secondary is quite a bit smaller than the primary (but not tiny); above resolution limit

    A 350 (16540+2906) mags 9.47/9.61; pa = 144°; sep = 0.630“, (2019.542, own measure; considered solid because in line with 4th Int. Cat. trend)
    345x:  possibly pointy (not resolved); faint!
    460x/averted vision:  barely resolved when seeing permits with the secondary appearing just a bit smaller versus the primary; at resolution limit; important data point to set faintness factor

    Image below is from 2019.542

    BU 627A, BC (16492+4559) mags 4.84/8.45; pa = 40°; sep = 2.116“, (orbital estimate for 2019.4; system is opening; value is in line with last precise [2.06”] and Gaia DR2 [2.105”])
    345x:  easily split; both stars are white and secondary is quite small; above resolution limit
    Inverted image shown below is from 2017.501

    BU 812 (16071+1654) mags 9.06/9.36; pa = 96°; sep = 0.73“, (2011, last precise; data may be incongruent with historical 4th Int. Cat. values)
    345x/averted vision:  image moves past elongated to notched about 40% of time showing two similar magnitude, faint stars; a re-measure of both separation and delta mag is desired; considered a bit above resolution limit

    A 228 (17063+2631) mags 9.31/9.88; pa = 13°; sep = 0.658“, (2019.553, own measure; system is opening)
    345x/averted vision:  image is at the elongated/resolved border; discs are tiny—very faint!
    460x/averted vision:  resolved about 50% of the time; a bit above the resolution limit
    Note:  listed magnitudes are from Hipparcos, not Tycho
    Image below is from 2019.533

    HDS 2446 (17177+3717) mags 4.62/8.53; pa = 143°; sep = 0.918“, (2010, last precise; solid data)
    460x:  split ~100% of time on night of very good seeing; adding an orange filter to the optical train causes the secondary to nearly disappear which explains the exceptional difficulty experienced imaging this object; above resolution limit

    STF 2315AB (18250+2724) mags 6.57/7.77; pa = 115°; sep = 0.600“, (orbital estimate for 2019.4; solid data)
    345x:  merely a bit oblong
    460x:  moves past elongated to a snowman shape about 30% of the time—stars clearly of dissimilar magnitude; on border of resolved but never actually seen as resolved; appears to be just below resolution limit
    Inverted image shown below is from 2017.512

    BU 641 (18218+2130) mags 7.03/8.66; pa = 341°; sep = 0.78“, (2015, last precise; solid data)
    345x:  moves past pointy to resolved about 10% of the time; secondary is much smaller
    460x:  seen as split when seeing allows image to sharpen (~30% of time); above resolution limit

    STF 2339AB, CD (18338+1744) mags 7.45/8.67; pa = 277°; sep = 1.482“, (2018, last precise; likely solid data)
    345x:  easily split to show fine magnitude contrast pair with primary seen as white and secondary as light orange; above resolution limit
    460x/averted vision:  secondary [CD] now appears elongated—it has a rho value of 0.492” and is known as WAK 21CD—a very nice bonus!

    A 238 (18114+2519) mags 8.59/9.55; pa = 74°; sep = 0.632“, (2019.548, own measure)
    345x:  persistently pointy
    460x/averted vision:  moves past elongated to resolved 20% of time; secondary is tiny; at resolution limit
    Image shown below is from 2019.548

    A 2093 (18054+1624) mags 9.09/9.85; pa = 226°; sep = 0.642“,  (2008, last precise; data is old but considered solid)
    460x:  very faint, elongated rod that presents as resolved perhaps 5% of the time; at or slightly below resolution limit

    TDT 1042 (18461+1328) mags 8.85/9.65; pa = 274°; sep = 0.7“,  (2009, last precise; data is old, not solid)
    345x:  merely point; stars are faint
    460x:  sharpens to resolved from a rod shape about 10% of time; at resolution limit; re-measure of separation needed

    STF 2084 Zeta (16413+3136) mags 2.95/5.40; pa = 112°; sep = 1.373“,  (grade 1 orbital estimate for 2019.211)
    345x:  light orange secondary just touching bright white primary—beautiful!  Above resolution limit
    Image shown below is from 2019.452

    STF 2203 (17412+4139) mags 7.72/7.81; pa = 293°; sep = 0.757“, (2015.5, Gaia DR2; solid data)
    345x:  just split to two white stars—not difficult; above resolution limit

    Libra
    STF 3090AB (15087-0059) mags 9.09/9.34; pa = 287°; sep = 0.627“, (2017, last precise; little corroboration from 4th Int Cat.)
    460x:  elongated only; never resolved
    627x/averted vision:  never moved past elongated; below resolution limit; not sure why this object is so difficult—a re-measure of separation is desired

    I1269AB (15249-2322) mags 8.73/8.84; pa = 199°; sep = 0.654“, (2015.5, Gaia DR2; solid data)
    345x/averted vision (best conditions):  resolved to two white stars of very similar magnitude about 30% of the time; at or slightly above resolution limit; important data point to establish minimum rho value for calculator

    BU 225BC (14255-1958) mags 7.16/8.37; pa = 91°; sep = 1.285“, (2015.5, Gaia DR2; solid data)
    345x:  split 100% of time showing the primary as white and the secondary as light yellow and smaller; above resolution limit; a beautiful triple with the AB pair designated SHJ 179 or H N 80

    HJ 4756 (15197-2416) mags 7.90/8.27; pa = 242°; sep = 0.574“, (2015.5, Gaia DR2; solid data)
    345x/averted vision:  moves past elongated to notched 50% of time (never resolved)
    460x:  resolved 50% of time; discs are very small and appear similar in magnitude; a bit above resolution limit; important data point to establish minimum rho value for calculator

    A 81 (15089-0635) mags 9.43/9.76; pa = 41°; sep = 0.68“, (2005, last precise; data is old and scant)
    345x/averted vision:  rod only; stars are very faint
    460x/averted vision:  moves past elongated to resolved at most 5% of the time; below resolution limit; re-measure of separation desired

    Lyra
    HU 1300 (19202+3411) mags 8.92/9.56; pa = 184°; sep = 0.74“, (2015, last precise; data is solid)
    345x/averted vision:  mostly a single star, but possibly rod-shaped; faint!
    460x:  at most rod-shaped (never resolved); below resolution limit which makes this object an outlier—further investigation warranted

    A 703 (19072+4451) mags 9.01/9.28; pa = 189°; sep = 0.57“, (2010, last precise; likely solid data)
    as yet unobserved; important data point to establish faintness factor for resolution calculator

    BU 648AB (18570+3254) mags 5.34/7.96; pa = 243°; sep = 1.303“, (grade 2 orbital estimate for 2019.3)
    460x:  small brightening apart from the primary that sharpens to a small disc that is seen as split 50% of the time
    627x:  split 100% of time; secondary is much smaller, both stars appear white; above resolution limit

    Have you observed or imaged any of these double stars?  I would love to hear of your endeavors with these objects.  Are there other, similarly challenging objects in these constellations that I have missed?  Let me know.

    Nucleophile(Austin, Texas, USA), from an online thread entitled; 8 Inch Reflector Investigations. Part V: Corona Borealis, Draco, Hercules, Libra, and Lyra.

    Hu149_DRA.jpg

    STF 2054AB

     

    STF2054AB_DRA.jpg

    A350_HER.jpg

    STF2315AB_HER.jpg

    STF 2084 Zeta

     

    STF2084_Zeta_HER.jpg

    STF 2084 Zeta

     

    STF2084_Zeta_HER.jpg

    A238_HER.jpg

    Nucleophile(Austin, Texas, USA), from an online thread entitled; 8 Inch Reflector Investigations. Part V: Corona Borealis, Draco, Hercules, Libra, and Lyra.

    Excellent as always Mark!

    Here are some of my observations from your list, plus a few others you might try:

    Cou 610 AB: 8″ 667x: Notched/snowman at best moments.  B definitely fainter and almost blue.  Very faintly split, looks like a blue appendage.  20″ diffraction is too messy.

    STF 2107 AB: !! 12.5” This was a CDSA plot find, didn’t expect it to be special.  Yellow and orange pair, very close ~1.5″, 1 delta mag.  Very pretty.

    STF 2315 AB: 12.5” 553x.  Near contact / overlapping disks, 0.5 delta mag.

    BU 641 AB: 12.5” 553x. !! Extraordinary!  Moderately bright A and much fainter B, <1″ separation.  Seeing needs to still.

    STF 2339 AB-CD: 20”: 533x: White and dull white B. Close but well separated, ~1″ [AB-CD seen. AB is Hu 322 1 delta mag 0.2″, not noticed]

    STF 3090 AB: 12.5” Notched to hairline split at the best moments. Faint pair, tough. Seeing not good enough to go above 553x. [AB seen; AC fainter and wider.]

    BU 648: 8″ 333x: 3 delta mag, at first diffraction, needed critical focus and seeing.

    OTHERS:

    Met 9: 8″ 205x nothing.  8″ 410x suspect elongation.  667x see a fleeting, bluish point just outside of first diffraction ring.  A is light yellow orange and bright; 2 delta mag. to B.  A feels elongated / egg shaped.  At 20″ and 667x the seeing is too messy though there is a knot in the diffraction where I had noticed the point with 8″.  Strong feeling A is elongated.
    12h 54m 39.98s +22° 06′ 28.8″ P.A. 51 sep 1.7 mag 5.70,7.77 Sp F8V+M2-3V dist. 33.85 pc (110.42 l.y.)

    STF 1967 = Gamma CrB: Definite mis-shape, oval to egg.  8″ 667x.
    15h 42m 44.57s +26° 17′ 44.3″ P.A. 104.6 sep 0.22 mag 4.04,5.60 Sp B9V+A3V dist. 44.78 pc (146.07 l.y.)

    STF 2289: Just split in 20″ at 205x, but flaring. 333x had messy diffraction. 8″ mask at 333x gave clean disks, split, ~0.7″. Dull yellow and yellow-red colors.

    18h 10m 08.69s +16° 28′ 35.0″ P.A. 215.3 sep 1.24 mag 6.65,7.21 Sp A0V+G0III dist. 263.85 pc (860.68 l.y.)

    STT 359: !! Kissing 8″ 333x, hairline split 667x. 20″ too diffracted. Near equal white A and bluish white B.
    18h 35m 30.40s +23° 36′ 19.9″ P.A. 3.7 sep 0.75 mag 6.35,6.62 Sp G9III-IV dist. 144.3 pc (470.71 l.y.)

    A 260 AB: 20″ 667x: At 8″, small and faint suspected split at 333x: 8″ 667x stars are hazy. At 20″ 667x got a clean wide split two hard paints of stars.
    18h 57m 34.07s +32° 09′ 20.2″ P.A. 244 sep 0.8 mag 9.17,9.60 Sp A0

    STF 2422: 8″ 333x: Excellent hairline split at 333x with 8” mask. Near equal white stars. Picked them out in a crowded field, suspected elongation right away, split with seeing as I centered it in eyepiece, and from then it was a steady split
    18h 57m 07.83s +26° 05′ 45.1″ P.A. 68 sep 0.8 mag 7.93,8.25 Sp A2IV dist. 156.25 pc (509.69 l.y.)

    AGC 9 AB = Sulafat: 8” 533x: B star immediately picked out of A’s glow like a piece of debris suspended in the explosion, or a planet hanging in the halo.
    18h 58m 56.62s +32° 41′ 22.4″ P.A. 307 sep 13.5 mag 3.24,12.10 Sp B9III dist. 190.11 pc (620.14 l.y.)

    HO 92 AB 20″ 667x: ! Beautifully well split, had an instant of perfect images. White pair near equal.
    19h 00m 59.89s +32° 33′ 11.6″ P.A. 40 sep 1.3 mag 10.59,10.85

    COU 1156 AB 20″ 667x: ! Near qual small and at best moments a clean split, still, just nice points. great star.
    19h 00m 34.25s +33° 01′ 24.8″ P.A. 111 sep 0.7 mag 11.14,11.25

    STF 2461 AB = 17 Lyr: 20″ 667x: ! Huge delta mag. B is obvious in 20″, though A’s diffraction was horrible. Used 8” mask to clean it up but the B star momentarily disappeared, though I could eventually pull it back out with seeing and critical focus. 4 delta mag.
    19h 07m 25.58s +32° 30′ 06.2″ P.A. 281 sep 3.2 mag 5.26,9.10 Sp F0V dist. 41.58 pc (135.63 l.y.)

    mccarthymark(San Francisco, California, USA), from an online thread entitled; 8 Inch Reflector Investigations. Part V: Corona Borealis, Draco, Hercules, Libra, and Lyra.

     

     

    To be continued…………………..

     

    Neil English unearths plenty more historical evidence testifying to the prowess of Newtonian reflectors in his large historical work, Chronicling the Golden Age of Astronomy, newly published by Springer-Nature.

     

    De Fideli.

     

    Product Review: Zeiss Terra ED 8 x 25 Pocket Binocular.

    The Zeiss Terra ED 8 x 25: a noble gesture from a market-leading optics firm.

    October 1 2019

    Preamble;

    Review A

    Review B

     Review C(verified purchaser):

    Although I read glowing reports for these pocket Zeiss Terra ED 8×25 light carry binoculars, my previous 4 month ownership of the Swaro CL 8X25 pockets had tempered my expectations. However, I found these small glassing gems to perform optically and ergonomically within 95% of the venerable and well built CL’s (at 1\3 the price)! They, just as the CL, have handling and comfort limitations compared to compact or full size binoculars. But for quick trip non-intrusive viewing, ease of portability and very accurate powered views, these little pockets are hard to beat. Overall, they possess very nice ergonomics, have natural color presentation, crystalline resolution that is real sharp and bright, with very good contrast views. Their FOV (field of view), whose sweet spot extends to within 10% of their wide 357ft limit, has a comfortable and stereoptic DOF (depth of field) . Hinge tensions are perfect, and the focuser is fast, going from close focus (mine’s about 5ft) CW to infinity in just 1.25 turns. Eye cup adjustments lock fully in (for eye glass wearers) and fully out (non-eye glass wearers). My vision is 20\15 and with the very comfortable eye cups fully extended and resting on my brow, I can align the small EP (exit pupil=3.1) with my pupils, gaining a full unobstructed sigh picture! With its ED glass, CA (chromatic aberrations) is well controlled and I find day light\low light viewing to be bright, natural and enjoyable! Diopter is set on the front dial (for the right barrel) and has enough resistance to stay put. Made in Japan for Zeiss, they offer a lot of features and performance at a great value point. These will make great travel companions and will be back-ups for my full sized field excursion instruments!

    Review D(verified purchaser):

    I also read about these on an astronomy forum, where I got the “use” info below, but not the specs.
    Buy these now. A best buy. Here’s why:
    1. Zeiss is a world class optics company. So is Swarovski.
    Compare this Zeiss Terra ED 8×25 to the world-class Swarovski 8×25 at $819 on Amazon (list price is even higher). This will show you
    a) specs are same: field of view (6.8˚),
    brightness (14.1 vs 14.2),
    weight (11 vs 12 oz),
    eye relief (16 vs 17mm), and
    size in inches
    b) specs favor Swaro: water resistant to 4 meters (vs 1 meter for Zeiss)
    c) specs favor Zeiss: close focus 6.2ft (vs 14.2 for Swaro),
    operating temperature -20 to 144˚ (vs -13 to 131 for Swaro)
    d) use favors Swaro: view is said to be more comfortable to look at, ergonomically
    focus has lighter touch, for those who like that
    e) use favors Zeiss: view is more crisp, contrasty (Swaro view is said to be softer, more milky)
    focus has firmer touch, for those who like that
    f) price favors Zeiss: $293 (vs $819 for Swaro)2. Compare them to other Zeiss binos from the SAME series – Zeiss Terra ED.
    – 8×25, 10×25 are made in Japan
    – 8×25, 10×25 are getting great reviews, for small binos
    – all larger Terra ED models are made in China
    – all larger models are getting panned for poor optics and build quality
    I think everybody is well aware that China optics and build quality are inferior (so far) to those from the US, Japan, Taiwan, Germany, Austria, etc.So this 8×25 model is unusual. Superior optics and build are normal for Zeiss, except for their Chinese built Terra ED line.
    Luckily, the 8×25 model is made in Japan with Zeiss design. This results in typical world class Zeiss quality.What is hard to understand is how Zeiss makes a $293 optic that arguably outperforms an $819 Swarovski.For bino newbies looking at 10×25, remember: the 10×25 will have a smaller exit pupil, so your views may black out more. Also, a 10x is way harder to hold steady and actually see than an 8x. So, even though you think you want 10x, you probably really want 8×25. With the 8×25, you’ll actually see and enjoy the view more.………………………………………………………………………………………………………………………………..

    What you get:

    The Zeiss Terra ED 8 x 25 pocket binocular kit.

    The Zeiss Terra pocket arrived double-boxed. After opening the outer packaging, the binocular kit was housed inside a very nicely presented box with a very fetching design which folds open to reveal the contents. Unlike other products I’ve received in the past, the Zeiss box has depicted on the inside, a colourful alpine scene with majestic mountain peaks soaring high above a beautiful river valley. Perhaps the team at Zeiss intended the user to explore such landscapes? Whatever the reasoning behind it, it was certainly a pleasant touch.

    With Zeiss, even the packaging is premium.

    Unlike customers who bought the Zeiss pocket binocular when it was first launched just a few years ago, I was relieved to see that the instrument was housed inside a small clamshell case with a magnetic latch carrying the blue & white Zeiss logo.The box also contained a lanyard, operating instructions and a lens cleaning cloth. I was surprised that the binocular itself came neither with eyepiece or objective lens caps, but I suppose they are not really necessary, as the case very effectively protects the instrument from dust and moisture.

    The box has the serial number on the side, which is needed to register the product on the Zeiss sports optics website.  On another side of the box, the detailed specifications of both the 8 x 25 and 10 x 25 models are presented; another nice touch.

    The binocular was housed inside the clamshell and was pristine, with no dust on the lenses, or gunk on the interior of the barrels. From the moment I prized the neatly folded instrument from its case, I was impressed. The frame is composed of a fibre-glass like polymer, with a fetching black, grey and blue livery. The sides of the binocular have a rubberised exterior making it easy to grip well while in use. The double-hinges were rigid and hold their positions solidly once the correct inter-pupillary distance is chosen for your eyes. The optics are hermetically sealed, nitrogen purged and had immaculately finished anti-reflection coatings on both the ocular and objective lenses. They are also treated with a Zeiss’ proprietary hydrophobic coating that encourages any moisture and grime that gathers on the lenses to fall off, rather than accumulating on the surfaces. The instrument is guaranteed to operate flawlessly over a very impressive temperature range: -20C to +63C, so covering almost any environment it is likely to find itself in.

    The binocular is water resistant, but to what degree remained a bit of a mystery owing to the rather odd way in which Zeiss chose to present it: 100mbar.

    You what mate?

    Thankfully, some physics knowledge helps to clarify the reference to water pressure.

    P = Rho x g x h, where P is the water pressure, Rho is the density of water, g is the acceleration due to gravity and h is the depth in metres. Rearranging to find h gives;

    h = P/ (g x Rho) = 10^4/ (10 x 10^3) = 1m

    Knowledge is power lol!

    So, not as waterproof as a Swarovski pocket binocular(I think it’s 4m) but adequate for most purposes.

    Fully folded down, the Zeiss Terra pocket is about 70mm wide and 110mm long. The oversized barrels make the Zeiss a wee bit taller when placed on its side in comparison to a classic pocket instrument, like my lovely little Opticron Aspheric LE;

    The Zeiss Terra Pocket(right) is a little wider and taller than the more conventional Opticron Aspheric(left).

    The Terra weighs in at 310g, so about 40 grams lighter than the Swarovski-made counterpart. Lighter isn’t necessarily better however, as some individuals find holding such light glasses problematical. But once unfolded, the significantly wider barrels more than make up for its low mass, as I shall explain more fully a little later in the review.

    The eyecups look a bit suspect, but once you begin rotating them, they work really well. They have no indents but do have ample friction. There are only two positions; fully retracted or fully extended. You know you’ve reached either situation by hearing their clicking into place. They are very solid and hold their positions superbly. Eye relief is 16mm and I was able to enjoy the full field with eye glasses on or without. Placing your eye on the eyecups is very comfortable, with their soft, rubberised overcoat and the large field lenses makes for very easy centring of your eye sockets along the line of sight of the optical train.

    The dioptre(+/- 3) setting lies at the other end of the bridge(near the objectives), which initially presented some problems for me, as it is rather stiff and difficult to get going, but once you’re done you’re done! The focusing wheel is centrally located and is reassuringly large and easy to grip, even with gloves on. It moves very well, with the perfect amount of tension. Motions run smoothly, with little in the way of play or backlash when rotated either clockwise or anti-clockwise. The focuser requires one and a half full rotations to go from one end of its focus travel to another.

    The Zeiss Terra ED 8 x 25 has a large, centrally placed focuser. The right-eye dioptre ring is located at the other end of the instrument, near the objective lenses.

    The objective lenses are very deeply recessed, more so than on many other pocket binoculars I’ve used. This affords the 25mm objective lenses greater protection against aeolian-borne dust and also serves as a first-line defence against glare. Cool!

    As the other reviewers showcased earlier, the Zeiss Terra pocket binoculars are manufactured in Japan, with the larger models originating in China under Zeiss supervision. You can see that quite clearly by examining the under belly of the instrument:

    The underside of the binocular reveals its country of manufacture: Japan.

    That said, and contrary to what the other reviewers have asserted, I don’t fully subscribe to the notion that all Chinese-made binoculars are inferior to those produced in Europe or Japan, as I shall elaborate on later.

    All in all, it’s pretty obvious that a great deal of sound engineering was put into these pint-sized field glasses.

    Handling: The Zeiss pocket is supremely comfortable to use, the slightly larger frame fitting comfortably in my hands. Indeed, with its wide field of view and thicker barrels, it feels like you’re peering through a larger instrument. The big eye lenses make it easy to get the right eye placement with none of the blackouts I’ve experienced on a number of other pocket binoculars. Its light weight means that you can carry it round your neck for hours on end with no neck strain. Its easy to get both hands resting on the central bridge, using my little finger to engage with the focus wheel.

    Optical Assessment:

    Straight out of its case, the Zeiss Terra impressed. Looking at some tree trunks just beyond my back garden fence reaveled a wealth of high contrast detail. I was immediately taken aback with the expansive field of view; not only was it wide, but the image remained tack sharp across nearly all of the field. Images snapped to a very sharp focus and I experienced no trouble focusing from just a few yards away all the way out to some trees located hundreds of yards away. Glare suppression looked excellent, even when pointed at some backlit scenes strongly bathed in sunlight. It was immediately clear to me that I was looking through a very high quality optical instrument.

    As I stated in earlier blogs, I don’t really consider the inclusion of low dispersion (ED) glass as necessary in a small binocular like this, but it’s a nice feature when presented as part of a larger, properly designed system. After all, and as several other reviewers pointed out, the Zeiss seemed quite comparable to arguably the most sought-after pocket binocular on the market; the venerable Swarovski CL pocket binocular. But what is not widely communicated is that the latter achieves all its optical excellence without using ED glass. That should send a powerful message to the gayponaut propagandists. No, its all about using great glass, great coatings and solid mechanical engineering. Alas, I was not able to compare this pocket binocular with the Swarovski, but the fact that the little Zeiss was often mentioned in the same company as it speaks volumes about its optical quality.

    Further daylight tests showed that off-axis aberrations were very well controlled. Even at the edge of the field pin cushion distortion and field curvature were minimal. Looking straight up at a denuded tree branch against an overcast sky showed no colour fringing on axis but as the image was moved off axis, some slight secondary spectrum was noted. Overall, I was very impressed at the Zeiss’ optical quality; it really does exactly what it says on the tin!

    A niggly moment: While the little Zeiss pocket binocular fits perfectly inside its small, clamshell case without the supplied neck strap attached, I found that the addition of the strap made it very difficult to get a snug fit. Wrapping the neck strap around the central bridge simply didn’t allow the case to close properly(the magnetic latch never stuck), but after several attempts experimenting with different approaches, I finally hit on a way to get the binocular with its strap on to fit the case. The trick involves wrapping the strap tightly around the ocular lenses.The latch sticks.  Problem solved!

    More discriminating optical tests:

    Flare & Glare assessment:

    Even if the glass used in binoculars were mined from the asteroid belt, it counts for nothing if it can’t control light leaks. My initial daylight tests showed that glare and internal reflections were very well controlled in the little Zeiss binocular, but they can’t tell the whole story. So, I set up my iphone torch at its brightest setting in my living room and examined the focused images through  the Zeiss Terra, comparing its results with my Opticron Aspheric(a nice little performer) as well as my control binocular; the Barr & Stroud 8 x 42 Savannah, which has excellent control of stray light.

    The results were very interesting. The Zeiss faired better than the Opticron, but not by much. However, it was not as good as the Savannah, which exhibits exceptional control of internal reflections even though it collects far more light than any pocket binocular.

    Further testing of the binoculars on a bright street light revealed some additional information. Internal reflections were well suppressed in both the Zeiss and Opticron binoculars, but the Zeiss showed more prominent diffraction spikes. The Savannah control binocular, in comparison, proved superior to both pocket binoculars. It shows very little flaring and internal reflections and much better control of diffraction spikes.

    And therein lies an instructive lesson. The Barr & Stroud Savannah 8 x 42 is fabricated in China yet shows exceptional control of glare and internal reflections. So, it’s not so much where a binocular is built that counts so much as how it is constructed.

    An exceptional, Chinese-made binocular; the Barr & Stroud 8 x 42 Savannah wide angle 143m@1000m.

    It is all the more remarkable, since the Savannah can be purchased for half the price of the diminutive Zeiss!

    All in all, these tests showed that the Zeiss binocular is very well protected against stray light, glare and internal reflections and this goes a long way to explaining why the views through it are so compelling.

    Collimation and Field of View Tests:

    I checked the collimation of the barrels on the Zeiss by placing the instrument on a tall fence and aiming at a rooftop, checking that both the horizontal and vertical fields correlated with each other. They matched up very well.

    Field of view is best assessed by turning the binocular on the stars. Accordingly, I aimed the Zeiss Terra at the two stars at the end of the handle of the Ploughshare, now low in the northern sky. The Zeiss was able to image both Mizar and Alkaid in the same field with a little bit to spare. These stars are separated by an angular distance of 6 degrees 40′ (or 6.66 degrees). This result was consistent with the specifications on the inside of the box; 6.8 angular degrees.

    Further Observations:

    Comparing the Opticron Aspheric to the Zeiss Terra in daylight, showed that both instruments were about equally matched in terms of sharpness( the aspherical oculars on the Opticron certainly help in this regard), but I could discern that the image was that little bit brighter in the Zeiss. Better coatings in the Zeiss binocular throughout the optical train give it the edge in this regard. Field of view was also much more expansive in the Zeiss( the Opticron has a true field of 5.2 degrees in comparison). Colours were also that little bit more vivid in the Zeiss pocket binocular, caused perhaps by its better contrast and superior control of chromatic aberration.

    Close focus is very good. I measured the Zeiss Terra to have a minimum close focus distance of 1.4 metres, so this should be a great little instrument for use as a long distance microscope, to spy out insects, fungi, flowers, rocks and the endlessly fascinating complexities of tree trunks.

    The eye lenses on the Zeiss Terra pocket binocular measure 18mm in diameter, the same as the Swarovski CL pocket. But they are still small in comparison to a larger format binocular like my 8 x 42.

    But while the field of view is quite immersive in the Zeiss Terra, it lacks the majesty factor of a larger binocular, such as my Barr & Stroud 8 x 42 Savannah, with its whopping 8.2 degree true field and better eye relief. Larger binoculars are simply easier to engage with your eye sockets and are thus more comfortable to use than any pocket binocular on the market.

    Performance under low light conditions easily show the limitations of the small objectives on the Zeiss Terra. At dusk, the 8 x 42 was vastly superior to the Zeiss, showing much brighter images, as expected. So, as good as the Zeiss pocket binocular is, it can’t defy the laws of physics.

    A Walk by the River Bank

    River Endrick, near my home.

    One of the best reasons to own and use a pocket binocular, is that it encourages you to go outside and explore the landscape. They’re so light weight and handy that anyone can carry one. Sometimes I use the Opticron and at other times I like using the Zeiss. Their sharp, high-contrast optics deliver wonderful images of the Creation. For me, nature is life affirming; a profound source of revelation and illumination. Like a great Cathedral, it fills me with awe and wonder. The sound of the wind whistling through the trees, the babbling brook and the noisy chirps of small tree birds form part of a symphony paying homage to the One who fashioned it all. For some, the Darwinian, materialist lie has dulled or even extinguished the sense of wonder that is innately endowed to every child. Dead to the world, believing themselves to be highly evolved animals, they pose no meaningful questions and can give no meaningful answers to life’s biggest conundrums. As you think, so you are.

    But it doesn’t have to be that way!

    For me, being able to explore the wet and wild places with tiny optical aids is a source of unending joy. On sunny afternoons or early in the morning, I sometimes take myself off for a walk along the banks of the River Endrick which meanders its way through the beautiful valley in which I live. Streches of shallow, fast-flowing water predominate but are also complemented by deeper pool and riffle sequences; favourite haunts of  Brown Trout, Perch and other course fish. Lanky Herons frequent these waters in search of fresh prey.  Bracken flourishes all along the river, and my pocket binocular allows me to study their shape and form in great detail. As summer gives way to autumn, their bright lorne hues transform into various shades of brown and tan. Spiders weave elaborate but deadly webs of silk with their spinnerets that sparkle and glisten in the morning sunlight, creating a wondrous decoration that I can experience up-close and personal with my long range microscope.

    Towering trees soar into a blue sky by the banks of the Endrick.

    Many species of tree grace the banks of the river; Ash, Silver Birch, Sycamore, Horse Chestnut and even the odd Oak. Thriving from frequent rain showers, their trunks are covered in lichens, moss and algae that reveal a wealth of intricate structure and a riot of colour that changes in accordance with the varying altitude of the Sun as it wheels across the sky. I especially delight in observing the colour of autumn leaves in bright sunlight, the ruby reds of anthocyanins and the yellow-orange hues of carotenoids. Every now and then, I watch as the fast-flowing water, dappling in weak autumn sunshine, ferries off fallen leaves, their destinies unknown. My pocket binocular shows me that every tree trunk is unique. Each tells its own story, visual scars of its past life.

    On some stretches of the river bank, I can still find some late-flowering wild plants that delight the eyes with colour in unexpected ways. And as autumn continues its march towards winter, the thick brambles begin to yield their succulent fruit. What could me more pleasing and more natural than to feast on their nutritious berries?

    An expected riot of autumn flowers observed along the river bank.

    At some places along the river bank, there are expansive rocky stretches. And yet every stone you unturn reveals even more of God’s Creation. A scurrying earwig, a wondrously armoured wood louse or a frollicking spider.The pocket binocular brings everything into stunning clarity. And though at first glance, each stone looks more or less the same, my little pocket spyglass shows that they too are all unique. Every crevice, every colourful grain is one of a kind.

    A rocky stretch along the river bank.

    This tiny corner of the world is ripe for exploration, with every day that passes presenting new adventures, new wonders to delight the eye. But so is yours!

    Bird Watching with the Zeiss Terra Pocket Binocular:

    Can good pocket binoculars be suitable for birdwatching?

    Lots of birding websites don’t recommend using pocket binoculars for birdwatching, citing their small fields of view and reduced comfort compared with larger binoculars as the most common reasons. Having used these small binoculars for a while now, I must say  that I respectfully disagree. The Opticron Aspheric has served as a good birding binocular for me, especially for quick looks at birds that visit our back garden table and the crows that nest in the conifer trees in the common ground beyond our back yard fence. Recently, a group of five magpies have taken up residence in the Rowan tree in our back yard. Each evening as darkness falls, they hunker down in the tree and don’t seem to be fazed by us turning on an outside light or noisy disturbances when it’s time to put the garbage out. During the day though, they are often seen chackering away at each other loudly(magpies don’t actually sing) as if to resolve some dispute among themselves. Further afield, there is a small pond just a few hundred yards away in the grounds of Culcreuch Castle, which attract quite a few varieties of water bird; swans, duck, water hens, heron and even the odd cormorant. Once I learned to use them properly, small binoculars like these have never presented much in the way of a problem for me.  And since the Zeiss Terra pockets have a nice wide field of 6.8 degrees, they have proven to be better suited than the Opticron in this regard because you can better track the motions of birds with a wider true field.

    On the Zeiss Sports Optics website, under ‘usage’, they seem to be saying that the Terra pockets are less suitable for birding, but I wonder if this is merely a clever ploy to get folk to buy into their larger(and more expensive) models. If so, they’re lost on me. With their excellent optics and generous field of view right to the edge, they can and do serve as good birding glasses. Of course, you can only form your own opinions by actual field experience but you may discover that the little Terra is all you really need! Seen in this light, acquiring a Zeiss Terra pocket binocular can actually serve as a cost-saving measure that stops you haemorrhaging your hard-earned cash on ever bigger and more expensive models.

    How About Astronomy?

    A small binocular like this is not the best for exploring the night sky since its small objective lenses cannot gather enough light to really wow the observer. However, the Terra’s excellent performance both at the centre of the field and extending nearly all the way to the edges, as well as its wonderful contrast make star gazing a pleasant experience. Out here in the sticks, the sky is quite dark and rewarding, even when observed with such a small instrument. Its field of view is large enough to enjoy some of the showpieces of the sky like the Pleiades, the Hyades, and larger asterisms such as Melotte 20 in Perseus, which can be taken in with its generous field of view. Stars remain very tightly focused and pin sharp across the field. Later in the season, I look forward to exploring the winter constellation of Orion the Hunter, to seek out its magnificent nebula in his Sword Handle, as well as the many delightful clusters of stars that are framed within its borders.

    On another autumnal evening, I was able to pick up the three Messier open clusters in Auriga, M34, the Messier galaxies, M81 and M82, the Andromeda Galaxy, the Double Cluster in Perseus, wide double stars like Mizar & Alcor and the Coathanger asterism in Vulpecula. Running the binocular through Cygnus and Cassiopeia will also reward dark-adapted eyes with innumerable faint stars, like fairy dust on black velvet. One delightful little project involves exploring the lovely colours of bright stars such as blue-white Vega and Sirius, creamy white Capella, brilliant white Rigel, orange Arcturus and fiery red Betelgeuse and Aldebaran.

    Following the phases of the Moon can also be a rewarding and worthwhile pursuit, as the Terra’s above average glare and internal reflection control will ensure that you get nice crisp, contrasty images. Lunar eclipses can also be enjoyed. You might also like to try your hand at observing the beautiful light shows presented by clouds passing near the Moon on blustery evenings. The excellent contrast of the Terra will also allow you to see stars around the Moon which can be very arresting to observe. Capturing the bright Moon as it rises over man-made buildings will also delight the eye. Above all else, don’t let its small aperture deter you from exploring God’s wonderful creation, which fills the Universe with hope and light.

    Final thoughts:

    Terra: for exploring the Earth and beyond.

    The Zeiss Terra ED 8 x 25 pocket binocular is a fine, high-quality optical instrument that is easy to use and transport. If taken care of, it will give you years of enjoyment where ever you wish to take it. As I said from the outset of this blog, I believe Zeiss did something very noble in bringing this little binocular to market at the price point they set. To be honest, and as others have quipped, they could well have stuck a ‘Victory’ label on it and no one would be any the wiser. Optically, Zeiss engineers have cut no corners to deliver an ergonomic, durable and optically sound instrument that will delight anyone who looks through it. I suspect that the Zeiss Terra pocket might be one of their best-selling products. It is even available on finance and buy-now-pay later schemes here in the UK, although I would strongly advise would-be buyers to save up and pay the price in full rather than incurring more debt, where you ultimately pay more. The Zeiss is expensive as small binoculars go, but I feel that it’s worth every penny, as for me at least, it has already given me countless hours of wonderful experiences. In the world of high-quality pocket binoculars, the Terra certainly stands out in a crowd. Highly recommended!

     

    Thanks for reading.

     

    Neil English is the author of a large medley of essays(650pages), Chronicling the Golden Age of Astronomy, which showcases the extraordinary lives of amateur and professional astronomers over four centuries of time.

    Post Scriptum:

    1. The Zeiss Terra has a two year warranty, which is enacted once you register the product on the Zeiss website. Cross-checking is thorough, requiring the serial number, and the name & address of the place of purchase. After checking these details, you receive a confirmatory email from the Zeiss Sports Optics team, welcoming you to the world of Zeiss.

    2. The little foldable Zeiss Terra is very suitable for those adults with unusually small inter pupillary distances (closely spaced eyes) and children.

    3. The overall light transmission of the Zeiss Terra ED is 88 per cent. Source here. This is exactly the same as the Swarovski CL Pocket(non-ED just in case Pepperidge farm forgets, ken ) binocular. Source here. Zeiss Victory Pocket binocular light transmission is 91%. Source here.

    4. The family of magpies came back to the Rowan tree in my garden, as they always do, just before sunset. Here is a picture of four ( I think!) individuals settled in the tree branches at 20.09pm local time on the evening of October 6 2019.

    Wee magpies hunkering down for the night in my Rowan tree.

    5. After a week of abysmal weather, with endless cloud and rain, I finally managed to test the little Zeiss Terra pocket binocular on a very bright gibbous Moon at 10:25pm local time on the evening of October 10 2019, when it was within an hour of meridian passage. At the centre of the field, it delivered a beautiful, clean and razor sharp image with no false colour. The background sky was good and dark with little in the way of diffused light. Internal reflections were pretty much non-existent with the Moon in the centre of the field. Only when it was placed just outside the field did I detect some minor flaring. Moving the Moon to the edge of the field threw up some slight lateral colour, bluish at its southern edge, and green-yellow at its northern edge. These results were entirely consistent with my flashlight testing. This will be a useful Moon-gazing glass!

    De Fideli.

    Product Review: The Opticron Aspheric LE WP 8 x 25 Pocket Binocular.

    A fine compact binocular at a fair price.

    Tiny little pocket binoculars have grown on me.They can be supremely useful to those who value or need ultra-portability, when larger binoculars simply are unworkable. Their tiny size ensures that they can be carried in a pocket or a small pouch, where they can accompnay hikers, hunters, sports enthusiasts, bird watchers and nature lovers who delight in seeing the full glory of God’s created order. Frustrated by a lack of any credible reviews of a variety of models, I began a ‘search out and test ‘ program that would teach me to select models that offered good optical and mechanical performance, as well as good value for money.  As you may appreciate, this was far easier said than done, but in the end, I did find a model that I could trust to deliver the readies; enter the Opticron Aspheric LE WP 8x 25 binocular.

    Retailing for between £120 and £130 ( ~$175 US), the little Opticron pocket binocular didn’t come cheap. But good optics and mechanics are worth having, especially if the user intends to employ the instrument on a regular basis. As I explained, I chose this model based on the performance of a first generation Opticron Aspheric that I had purchased some time ago for my wife, possessing identical optical specifications to this newer model, but without having the additional advantage of being nitrogen purged, as well as being water and fog proof. In truth, I chose the original model without much in the way of research and with very little experience of what the market offered; Opticron is a good make, trusted by many enthusiasts for delivering good optical performance at a fair price.

    Opticron began trading back in 1970, founded as a small British family firm, and offering binoculars, spotting scopes and other related sports optics for the nature enthusiast. Since those founding days, Opticron has continued to innovate, where it now is a major player in this competitive market, offering well made products catering for the budgets of both novices and discerning veterans alike. And while some of their less expensive models are made in China, many of their high-end products are still assembled in Japan.

    What you get.

    What your cash buys you: The Opticron was purchased from Tring Astronomy Centre. It arrived double-boxed and with no evidence of damage in transit. You get the binocular with both ocular and objective covers, a high quality neoprene padded case, a comprehensive instruction manual & warranty card. The details of that all-important warranty are shown below:

    Details of the warranty.

    After a few days of intensive testing I was satisfied that I had received a high quality instrument and so I elected to register my binocular on the Opticron website.Owners are not obligated to register the instrument in this way however, as all that is required is proof of purchase, should any issue arise with the instrument in normal use.

    Binocular Mechanics: The Optricron Aspheric LE WP 8 x 25 is a classically designed pocket binocular with a double-hinge designed allowing the instrument to fold up into a very small size that can be held in the palm of your hand. The hinges have just the right amount of tension, opening up and holding their position even if held with one hand.

    The focuser is slightly larger than the first-generation model, and has better grip, allowing you to use it even while wearing gloves. The barrels and bridge of the binocular are made from aluminium, overlaid with a tough, protective rubberised armouring. Compared to the first-generation model,  the new incarnation induces more friction with your fingers, an important feature if it is to be used for extended periods of time.

    The New Opticron Aspheric LE is now water and fog proof.

    Initially, I found that turning the focuser to be a bit on the stiff side, but after a few days of frequent use, I became used to it. Turning the focuser either clockwise or anticlockwise showed that there was no backlash, moving smoothly in either direction. The instrument has an integrated neoprene lanyard which can be wound up around the bridge while being stored in its case. I very much like this rather understated feature, as there is no need to fiddle about attaching a strap. Out of the box, it’s ready to use!

    Using the Optricon Aspheric LE WP is child’s play; just twist up the eyecups and they click into place. There are no intermediate settings. If you wear glasses, leave the eyecups down.

    The twist-up eyecups have a soft rubberised overcoat which are supremely comfortable on the eyes. There are just two positions; fully down or fully up. Once twisted up, the cups lock in place and rigidly stay in place with a click. Eye relief is very generous(16mm), allowing eye glass wearers to engage with the entire field. I don’t use glasses while observing through binoculars, so I always pop the eyecups up while viewing through them. Optimal eye placement is very easy to find quickly, thanks to the large field lens, with none of the annoying blackouts I experienced on a few lesser models.

    The dioptre setting is located in a sensible place; right under the right eyecup. A small and very elegantly designed protruding lever on the dioptre ring makes it very easy to rotate either clockwise or anti-clockwise. It works well and stays in place even after repeatedly removing the instrument in and out of its small carry case.

    An elegant design feature; a small protruding lever under the right eyecup makes it easy to adjust the dioptre setting.

    I measured the interpupillary(IPD) range to be between 32 and 75mm, ample enough to accommodate most any individual. Moreover, the well designed dual hinges on the bridge ensure that once deployed they stay in place with little or no need to micro-adjust while in use. The Opticron pocket binocular weighs in at just over 290 grams.

    If the Opticron Aspheric pocket binocular were a car, it would surely be an Aston Martin.

    Optical Assessment: Although this tiny binocular does not have a stalk to allow it to be mated to a monopod or tripod, I was able to assess how well collimated it was by resting the binocular on a high fence, and examining the images of a rooftop some 100 yards in the distance, checking to see that the images in the individual barrels were correlated both horizontally and vertically. This was sufficient to affirm that the binocular was indeed well collimated.

    During daylight hours, the binocular delivers very bright and colour-pure images thanks to a well made optical system which includes properly applied multi-coatings on all optical surfaces, good baffling aginst stray light and silver coated prisms(boosting light transmission to 95-98 per cent). The binocular also has correctly executed phase coatings on the prisms to assure that as much light as possible reaches the eye. Sharpness is excellent across the vast majority of the field, with the aspherical optics minimising off-axis aberrations including pincushion distortion and field curvature. I wouldn’t be surprised if the overall light transmission is of the order of 80 to 85 per cent(revised in light of the tranmissitivity of the Zeiss Terra ED pocket glass with a light tranmsission of 88 per cent).

    One of my pet peeves is seeing glare in the image when the binocular is pointed at a strongly backlit scene. I was delighted to see that apart from very slight crescent glare  when pointed near the Sun, the images generally remained stark and beautifully contrasted. These good impressions were also confirmed by more stringent tests conducted indoors by aiming the pocket binocular at my iphone torch set to its maximum  brightness. These tests showed that although there was some weak internal reflections  and flare, they were well within what I would consider acceptable. At night, I was able to see that when the binocular was aimed at some bright sodium street lamps, only very slight ghosting was evident. Finally, aiming the 8 x 25 at a bright full Moon revealed lovely clean images devoid of any on axis flaring and internal reflections. Placing the Moon just outside the field did show up some flaring however, but I deeemed the result perfectly acceptable. You can chalk it down that these results are excellent, especially considering the modest pricing of the instrument.

    Colour correction was very well controlled in both daylight and nightime tests on a bright Moon. On axis, it is very difficult to see any chromatic aberration but does become easier to see as the target is moved off axis. That said, secondary spectrum was minimal even in my most demanding tests, affirming my belief that a well-made achromatic binocular can deliver crisp, pristine images rich in contrast and resolution.

    ……………………………………………………………………………………………………………………………….

    An interesting aside: My former colleague at Astronomy Now, Ade Ashford, reviewed a larger Opticron binocular- the Oregon 20 x 80 – for the October 2019 issue of the magazine. In that review, featured on pages 90 through 94, he confirmed what I had previously stated about larger binoculars with powers up to 20x or so; there is no need to use ED glass if the binocular is properly made and this goes for both daylight viewing and nightime observations. Below is Ashford’s assessment of the 20 x 80’s daylight performance:

    And here are his conclusions:

    Moreover, Ashford offers this sterling advice to the binocular enthusiast:

    ” …..don’t get hung-up on ED glass instruments. A well-engineered achromatic model will perform well, particularly if it uses Bak-4 prisms and its optical surfaces are multi-coated throughout.”

    pp 91

    Having ED glass counts for nothing if the binocular is not properly made. I would much rather have a well made achromatic instrument than have a poorly constructed model with super duper objective lens elements.

    …………………………………………………………………………………………………………………………..

    A fine quality pocket binocular in the plam of your hand.

    My Little Aston Martin:

    The little Opticron has already accompanied me on a few hill walks, a Partick Thistle FC( sad, I know!) testimonial and numerous rambles near my rural home, where it has delivered wonderful crisp images that never fail to delight. The field of view(5.2 degrees) is a little on the narrow side as pocket binoculars go, but its plenty wide enough for most applications and besides, the distortion free images nearly from edge to edge quickly override any perceived handicap of having a restricted viewing field.

    Its tiny size and lack of garish colouring make it the ideal instrument to bring along to sports events, where it doesn’t attract attention from fellow crowd members. The Opticron is also a most excellent instrument to examine colourful flowers, butterflies and other marvels of nature near at hand, thanks to its excellent close focus; measured to be ~51 inches.And because its waterproof, it would also make an excellent companion while sailing or fishing.

    The Opticron pocket binocular comes with a very high quality padded pouch to protect the instrument from any kind of rough handling.

    Of course, the power of a small, high-quality pocket binocular quickly dwindles as the light begins to fade in the evening, or during the attenuated light before dawn, where a larger field glass really comes into its own. A little pocket binocular like this is far from the ideal instrument for viewing the night sky, but it can still be used for the odd look at the Moon, a starry skyscape or brightly lit cityscape.

    I consider weatherproofing to be a sensible and worthwhile addition to any binocular and is certainly welcome on this second generation Opticron Aspheric. The instrument is purged with dry nitrogen gas at a pressure slightly higher than atmospheric pressure. This positive pressure helps to keep out dust and marauding fungi, and the sensibly inert nature of nitrogen ensures that internal components(including the silver coated prisms), will not tarnish or oxidise any time soon. This will only serve to increase the longevity and versatility of the binocular in adverse weather conditions, especially in my rather damp, humid climate. When not in use, I have taken to storing all my binoculars in a cool ( ~60 F) pantry with silica gel dessicant inside their cases. Yep, all my instruments are in it for the long haul.

    Quality you can wear.

    The Opticron Aspheric LE WP 8 x 25 is an excellent example of how a well made, achromatic binocular can deliver wonderful, sharp and high-contrast images. It is more expensive than many other pocket binoculars, but you most certainly get what you pay for.

     Thanks for reading!

    Neil English’s new title, The ShortTube 80; A User’s Guide, will hit the bookshelves in early November 2019.

     

    De Fideli.

    Ten Things True Christians Should Never Compromise Over.

    Person Hands on Holy Bible

    Finally, my brethren, be strong in the Lord and in the power of His might. Put on the whole armor of God, that you may be able to stand against the wiles of the devil.  For we do not wrestle against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this age, against spiritual hosts of wickedness in the heavenly places. Therefore take up the whole armor of God, that you may be able to withstand in the evil day, and having done all, to stand.

    Ephesians 6:10-13

     

    1. Defending the Doctrine of Creation: The Bible makes it very clear that all life on Earth was created by God. As we continue to probe the mysteries of life, we discover that it is vastly more complex and more wonderful than we could have ever imagined; an endless regress established by the Living God. An overwhelming body of evidence is now available for any reasonable person to critically appraise, which clearly shows that Darwinian evolution is not only demonstrably false but is, in the broadest sense of the term, an evil ideology. Claiming that humans or any other life forms evolved is not only delusional, it is also blasphemy. I would personally question any clergyman that honours or capitulates to the “monkey religion.” Best to stay well clear of it.
    2. Defending the Rights of the Unborn: Human life begins at conception; that is what modern science has established and what the Bible consistently teaches. Killing a human life in utero, apart from a few exceptional medical circumstances, is murder, plain and simple.
    3. Defending the Traditional Family: Both the Old and New Testaments affirm God’s desire for humans to maintain strong, traditional family units. Contrary to what you may have heard in recent months, there only two genders (the other 98 are products of sick, delusional minds). Sex was created by God to be enjoyed only within marriage and only between a man and a woman. God condemns all homosexual acts, declaring it “an abomination,” or in some other translations, “detestable.” The LGBT juggernaut has many characteristics in common with the Nazi movement of the early 1930s; bullying society to accept it as “good” and “normal”, when it is actually neither. They wish to destroy what God intended for humans. Christians should never succumb to pressure to normalize what God clearly considers evil or depraved.
    4. Universalism: The notion that all religions lead to God is commonly believed in our era, even by some who profess themselves to be Christian.  But that is not what the Bible teaches. Christ plainly stated that there is only one way to God and that He is “the door.” Christian doctrine divides; it is exclusive and uncompromising. It was intended that way.
    5. Defending the Sanctity of Human Life: The Bible teaches that all humans are made in God’s image and likeness and thus have great intrinsic value. It condemns all kinds of racism and the exploitation of one people group by another(including human trafficking and slavery). Replacement theology, the notion that the Church has replaced Israel, is not only unbiblical, it fans the flames of anti-semitism that is so prevalent in our societies today.
    6. The Inerrancy of Scripture: Christians should hold the Bible as their gold standard. Its timeless wisdom shows us how to live, what to accept and what to reject. It is not to be taken out of context and twisted to suit a particular agenda. Regular reading of the words of Scripture keeps you focused on what is important and what is not, even if wider society does not follow in the way. Just because society deems something as good, it doesn’t necessarily mean that it is right in God’s eyes.
    7. The Importance of Bible Prophecy: Many so-called ‘liberal’ Christians pay no attention to Bible prophecy. That is a grave mistake, as about 25 per cent of the Bible deals with prophecy. For example, all of the prophecies concerning Christ’s birth, ministry, triumphal entry into Jerusalem and suffering at the hands of Roman overlords were predicted with 100 per cent accuracy centuries before his birth, and Christ Himself fulfilled a whole string of other prophecies during his missionary years. Ignoring Bible prophecy is like trying to ride a bicycle without wheels. God clearly intends us to know some of the details of the future so that we can watch for the signs of His second coming. Ignoring such prophecies may well catch you off guard.
    8. Man’s Fallen Nature: The Bible teaches that humans were originally created to live harmoniously with God eternally, but after the fall in the Garden of Eden, man’s nature always goes from bad to worse without God being in the driving seat. This is counter to what humanists(their manifesto holds that we evolved and so are nothing more than smart animals) believe. When mankind disses God, the invariable result is moral decay and ever increasing depravity.
    9. The Divinity of Christ The Bible clearly teaches that Jesus Christ is the second member of the trinity(Father, Son & Holy Spirit). During His earthly ministry, Jesus demonstrated his equality with God the Father by His absolute submission to God’s will, as well as through His miracles and moral teachings. Liberal scholars want us to unhinge the person of Christ from any divine claim. We must constantly resist any suggestions that Christ was merely a good man or just a good teacher. Jesus, being fully God and fully human made a way for fallen humans to come into right standing with God. He is to be worshipped and revered for all eternity.
    10. The Importance of Sharing your Faith: Jesus taught us to share our faith and to  pronounce the good news of His coming to the ends of the earth. Recall the parable of the talents recorded in Matthew 25 (and echoed in Luke 19), where Jesus told of the foolish steward who received a talent from his master, but instead of investing it to make more, buried it in the ground, where it remained until his disapproving master returned. There is no such thing as having a ‘quiet faith.’ We are required to actively share our faith with others when any opportunity presents itself. Don’t bury the talent the Lord has given you. Do something with it! Win souls for Christ!

     

    Neil Englsih is the author of a large historical work, Chronicling the Golden Age of Astronomy, showcasing how the Christian faith was never a hindrance to the development of astronomical science.

     

    De Fideli.

     

    N=2: Why I’m the Very Proud User of a Barr & Stroud Savannah 8 x 42 Binocular.

    An alpha binocular in many ways, except for the price.

    Semptember 9, 2019

    I’ve said it before, and I’ll say it again: there is something in a name.

    In my ongoing investigation into binoculars, I’ve discovered that, like telescopes, you don’t always get what you pay for. In particular, if a product offers advanced optical features like a full multi-coating on all air to glass surfaces, ED elements, or phase corrected roof prisms, it doesn’t necessarily translate into a solidly functioning optic. I’ve tested products purported to have premium optics but upon inspection, did not deliver all the goodness that they were promising in cleverly devised youtube promos and fancy specification sheets etc.

    One company that has bucked this trend is Barr & Stroud, a once prestigious optical and engineering firm, established in Glasgow, Scotland, that at one time supplied all manner of optical instruments to the British navy during two world wars. Like many other large optical firms established in Britain, it underwent considerable re-structuring over the decades. Today, the brand name is owned by Optical Vision Limited(OVL) and began producing binoculars for the civilian market in 2011, moving production to China.

    My enthusiasm for the brand began just a year ago(2018), when I initiated testing a variety of their binoculars in different price ranges. Like many others who have looked through their instruments, I was duly impressed by the incredible bang for buck of their offerings, with optics that punched well above their modest price tags.

    Of particular note is the Barr & Stroud Savannah 8 x 42, which delivered wonderful, wide-field, high-contrast and colour pure images of the Creation. Unlike other brands in the same price range, which offered so-so performance, especially off-axis, these binoculars maintained excellent control of the same aberrations. The massive 8.2 degree field of these 8x glasses is sharp across the vast majority of the field, with only the extreme edges showing significant distortion.

    My first Savannah was actually purchased on the second-hand market, and that out of sheer curiosity. Expecting such a wide angle binocular to show average optical quality as one moves off axis(like so many others I’ve tested), I was very pleasantly surprised to discover that this excellent image quality was being maintained to the extreme edge of the field. Indeed, the view, in retrospect, was almost too good to be true. Unfortunately, the dioptre ring, which is situated in a very unusual place on this binocular (just ahead of the large focus wheel) developed a fault, which necessitated its return to OVL for repair. What I actually received was a brand-new instrument and so I was able to asess the performance of two samples of the Barr & Stroud Savannah that inspired the writing of this blog.

    Two great performers: the Barr & Stroud 8 x 42 Savannah(left) and the 10 x 50 Sierra(right).

    Built like a proverbial tank, the fully weatherproof and nitrogen purged Savannah 8 x 42 is heavier than many competing models on the market. Indeed, at 819 grams, it even weighs more than my 10 x 50 Barr & Stroud Sierra binocular (which also delivers excellent optics and mechanics for the buck). Outwardly, the Savannah has a rather Spartan look and feel about it, with features that are simple and rather understated. The eye cups are of very high quality, which can be set to three positions, and with a very generous 18mm eye relief, is ideal for eye glass wearers and those who like to observe without glasses. When twisted up, they click into place with a reassuringly loud “thwack” sound, and which remain in that position even after excess pressure is applied. Indeed, I rate these eyecups very highly and amongst the best that I have sampled thus far in my binocular education.

    The high quality multi-coatings on the 42mm objective lenses of the Savannah. The reader will also note how deeply recessed the objectives are. This helps suppress glare in bright, daylight conditions.

    The focus wheel is large and moves smoothly without any stiction, either clockwise or anti-clockwise, making it easy to change the position of best focus from as close as 2 metres to beyond infinity. The tension is just right; not too stiff and not too slack.

    All the accessories that come with the Savannah are of high quality; including a hard black clamshell case, a padded neck strap with the B&S logo and rubber objective and eyepiece lens caps that can be affixed to the binocular and so are not easily lost in routine field use. The instrument also comes with the company’s 10-year warranty.

    The large and responsive focus wheel on the Barr & Stroud Savannah 8 x 42.

    The new binocular turned out to be every bit as good optically than the first one I returned! Indeed, it could even be that little bit better! Images are bright and razor sharp, rich in contrast and colour pure. Though it contains no ED elements, the instrument shows only a trace of chromatic aberration, and only if you go looking hard for it. Like I said before, I don’t consider the presence of ED glass as a feature that is necessary on binoculars of this specification. Crank up the power nearer to the resolving magnification, and it’s a different story. But in this realm, what I’m more interested in, and which is far more important in the scheme of things, is how well the binocular is put together.

    Roofs are complex instruments, requiring engineering skill and very careful assembly of the components. Some firms know how to do it well, others don’t…..methinks.

    The high quality twist up eyecups on the Savannah click securely into place with a loud “thwack” sound. Note the tough, texturised rubber amouring covering the instrument.

    My assessment of binocular optics involves the usual procedures employed by other reviewers, but I have also devised much more demanding tests to learn how well the light is being transmitted though the optical train.  What I have discovered is that many purportedly high-end roof prism binoculars (based solely on their recommended retail price) often show considerable flaring and annoying internal reflections when observing strongly backlit daylight scenes. In addition, night time testing on bright artificial street lights and the full Moon also provide solid clues as to what is going on inside the test binocular(which unfortunately, are all hermetically sealed!!).

    One particularly stringent test is to direct an intensely bright beam of light from my iphone into the binocular to see how it deals with glare and internal reflections. No roof prism binocular, no matter how well made, can completely pass these tests;

    All fall short:- but what astonished me was how well they were suppressed in the Savannah 8 x 42. Unlike many other models, which reveal too much glare and bright ghosting across the field, both my 10 x 50 and 8 x 42 Barr & Stroud instruments came out with truly excellent results! In particular, the degree of glare suppression and control of internal reflections present in the Savannah was fully the equal of a world class binocular: – in this case, the Swarovski 10 x 42 EL Range:. Where you will often pick up diffraction spikes and flaring from bright street lighting in an inferior instrument, as well as contrast-robbing diffused light around such artificial light sources (not to mention internal reflections), my new Savannah 8 x 42 shows up very little. This is easily seen in regular daylight testing, where the images thrown up by the instrument show very high contrast, allowing very fine details to be easily discerned.

    Performing a small, bright light test in the comfort of my living room. Note the small amount of daylight left in the room to asist imaging objects immediately behind and around the light source(my iphone torch).

    I thought long and hard about why such an economical instrument offered such unreasonably excellent control of stray light, and then I remembered how the same company made high-quality optical instruments for the British navy. Out at sea, where sunlight is strongly reflected off the water, glare suppression would have been a high priority for any optic used for long distance surveillance. Although it remains an interesting conjecture on my part, it could be that the technicians who assemble such binoculars have specialised knowledge on how to keep those internal light leaks at bay. Afterall, once upon a time, not doing so might well have made all the difference between life and death!

    Some important details coming through on the focussing wheel. The ocular lenses are hard coated for extra durability.

    Whatever the reasons for such optical excellence, the wonderful colour correction, contrast and suppression of stray light make the 8 x 42 Savannah binocular an excellent choice for birders and naturalists. I cannot think of a better instrument – without dropping an additional few grand – to take along with me to observe the deluge of autumnal colours that are only just emerging, as the trees shut down for a long, winter nap. But, as I’ve discovered, the 8 x 42 also delivers knock-out views of the celestial realm!

    As I recall, it was with some trepidation that I decided to try the Savannah. I was leary of the advertised field of view -143m@1000m or 8.2 angular degrees. I had learned of other binoculars delivering such enormous fields of view but having disappointing off-axis performance. Better to have a binocular that delivers a smaller field of view with tightly focused stars near the edge than suffer the indignation of seeing those stars swell up in the outer part of the field. It’s just not tennis!

    But my fears were completely allayed once I tried them out on the night sky.  I was literally blown away! Not only was the field of view enormous, but it was very well corrected, right to the edge of the field. Believe me, I have experienced some real howlers, where stars are pinpoint sharp in the centre of the field but when moved off axis, the same test stars balloon into enormous blobs when positioned near the field stop. Starfields remain crisp throughout the field of the Savannah binocular making it an excellent choice for casual star gazing.

    Although the binocular can be mounted on a monopod for increased stability, I have rarely used it in this capcaity. Instead, I enjoy hand-holding the instrument where the 8x magnification makes it considerably easier to hold steady over a 10x instrument. That said, if I wish to push the instrument to see the very faintest stars, a monopod is a good way to go. Some binocular authorities I have read suggest that you can gain up to 1 stellar magnitude deeper if the image is stabilised.

    The very well corrected, ultra-wide field of the Barr & Stroud Savannah  8 x 42  provides stunning views of large clusters of stars. For example, it provides knock-out views of Melotte 20, otherwise known as the Alpha Persei Association, where the field is littered with several dozen hot, white stars varying in glory from the third to the 10th magnitude. But perhaps my fondest night time experience with this wonder binocular was seeing the entire Sword-Handle and Belt stars of Orion in the same field on a cold, dark December evening.  And where my 10 x 50 Sierra binocular can just frame the Hyades, the Savannah frames the same picturesque asterism with plenty of room to spare!

    The large, sensibly flat field of the Savannah has proven excellent for watching meteor showers. I just aim it at the radiant and watch to see if some shooting stars flash across the field. I also love exploring the interface between land and sky. Indeed, as described in this blog, the Savannah is my instrument of choice to explore Moon and starscapes rising above trees and buildings near my home. The Savannah has re-kinded my interest in observing the full Moon when the clouds pass over it. I adore the play of light and colour the binocular serves up in its enormous field of view.

    The 8 x 42 is always by my side while using my backyard telescopes. It has greatly increased the speed and efficiency of finding faint fuzzies. Once I locate the target with the binocular, the telescope is pointed at the same spot of sky where I can rapidly hone in on the object.

    A binocular that doesn’t want to go inside its hard case.

    Readers will forgive my rather vaunted praise of this amazing instrument. But I feel it is justified. In an age of con artists and let downs, this instrument is nothing short of a ray of sunshine. It offers exceptional value for money and has sated my desire to acquire anything else in this mid-sized binocular class. I can hand-on-heart recommend it to other observers looking for an excellent all-round binocular for day and night time use. You’ll not be disappointed!

    Thank you for reading!

     

    Neil English is the author of several books in amateur and professional astronomy.

     

     

    De Fideli.

    In Search of a Good Pocket Binocular.

    Far from the madding crowd.

    August 30 2019

    Pocket binoculars are a popular choice for many birders, hikers, ramblers and all-round nature lovers who want to get up-close and personal with God’s illustrious creation. If you have scenery like this right on your door step, trust me, you’ll be keen to take along some binoculars to enhance and extend what your eyes can see;

    A pocket binocular usually has objective lenses less than 30mm in diameter and offer magnifications anywhere from 7x to 10x. They are small and in general fit inside a pocket, giving rise to their name. Like all other binoculars, pocket glasses come in a range of prices, starting from just a few tens of pounds right up to £1000, depending on the make and model. The cheapest models are to be generally avoided, as they often have very shoddy optics and/or mechanics, but things get very interesting once you move into the mid-priced market, where you can acquire decent optics and mechanics for prices anywhere from £70 up to a few hundred pounds. But is buying a pocket binocular from a reputable optics firm a sure way to get decent quality? I’m going to have to concede that the answer is “no.”

    That’s based on my experiences mainly with two models from the well established companies: Bresser(Germany) and Kowa(Japan). Both models were acquired from amazon and possess similar optical specifications, the Bresser Pirsch 8 x 26mm and the Kowa SV 8 x 25mm DCF, which set me back £97.00 and £83.00, respectively. Both models are roof prism designs, have fully multi-coated optics and phase corrected prisms to maximise the amount of light that is transmitted to the eye, and to render colour-true images in bright daylight conditions.

    The Bresser Pirsch 8 x 26mm was exciting to unpack, as it looked the bizz from the online images and the specifications promising “premium quality worthy of their prestigious lifetime warranty.” And when I opened up the case to have a look at the binocular, I must admit to being instantly impressed; here was a stylish looking instrument with a beautifully made, ‘Swarovski like’ open bridge design. The focuser was large and constructed from high quality metal. In operation, it was a joy to use, moving with silky smoothness, with no stiction when turned clockwise and anti-clockwise through its travel.

    The Bresser Prisch 8 x 26 compact binocular.

    All the accessories were of high quality, which included a padded next strap, an oversized nylon case, instruction manual, rubber objective and eyepiece covers, and a lens cleaning cloth.

    The twist up eyecups are amongst the best I have encountered, clicking through a number of stages from fully retracted to fully extended.They hold their positions very well, even when significant pressure is applied to them. The dioptre setting is situated in a sensible place; just under the right barrel. It is stiff and once set in place it will not easily budge.

    The beautifully designed twist up eyecups are amongst the best I have personally encountered with four positions. Here they are shown fully extended.

    Handling this binocular was particularly pleasurable, as the open bridge design allows for firm gripping either with or without gloves, and can easily be focused using one or two hands. The binocular is lighter than it looks: ~ 290 grams

    Firm grip: handling the Bresser Pirsch 8 x 26 binocular.

    The Baader Pirsch 8 x 26 has outstanding mechanical quality.

    The instrument comes with quality accessories, including a padded cary case and quality neck strap.

    But mechanics are only half the story of any binocular. How did the optics fare?

    Collimation was tested by mounting the binocular securely on a monopod that was firmly sandwiched in place between two planks of wood on my garden fence, and examining the fields of view presented by both barrels of the instrument. This showed that the binocular was indeed well collimated, certainly within factory tolerances. I had no trouble instantly merging the images once the optimum IPD was selected. Close focus was estimated at about 6.5 feet, in line with the stated specifications. So far so good.

    The quoted eye relief for the Pirsch binocular is 15.6mm. That should have been plenty good for eye glass wearers. However, I found that only by pressing my glasses hard against my eyes could I observe the full field. It was not comfortable and so I think folk that have to use eye glasses when using this binocular will struggle.

    Testing collimation of the Pirsch binocular. And yes, this wee instrument does have a tripod connecting thread!

    True to the specifications, the binocular offers a fairly wide field of view. I measured it as about 6.6 degrees(in agreement with its stated FOV of 117m@1000m). Compared with an entry level test binocular with no phase coating(but with fully multicoated optics), the image was better corrected for seidel aberrations across the field of view, revealing noticeably less field curvature, pin cushion distortion and lateral colour than the entry level unit. On axis, no chromatic aberration could be seen at the edges of a nearby telephone pole as seen against a bright, overcast sky, while the control did show a little bit. And while the image looked good in many daylight scenes, it wasn’t long before I discovered that the binocular was not showing the contrast I had been enjoying with my wife’s Opticron Aspheric LE 8 x 25mm pocket binoculars. Looking into brightly backlit scenes revealed a potential problem with the Pirsch; there was some flaring and internal reflections coming through. So that caused me to investigate the matter further.

    A cursory examination of the binocular review literature revealed something rather shocking to me. Very few reviewers had the presence of mind to investigate and report back on light leakage within the binocular, which can lead to very incomplete knowledge on how an instrument ought to behave under real-life situations. I consider it essential information for any savvy buyer, as it doesn’t matter how well a binocular is appointed with high-tech features if they can’t manage to adequately suppress stray light in the optical train. To me, this is Optics 101.

    Fortunately, this is easily done by carrying out an indoor test using an iphone with its torch turned up to its maximum brightness and examining the in-focus images of how that light is delivered to the eye whilst looking though the binocular in a darkened room a few metres in the distance. You can also glean good information on how well a binocular will deliver by pointing the instrument at a bright street light or the full Moon(this is a considerably less severe test but an important one in any binocular assessment).

    Well, the tests were very convicting. Not only was there many bright internal reflections but the Pirsch binocular seemed to be causing bright light sources to become diffused across the field of view, manifesting as a contrast-robbing, circular haze. And it was the same when I pointed the binocular at a bright sodium street light.  I had not seen such terrible control of stray light since the day I tested a very inexpensive Celestron Nature DX 8×25 unit several months back. Needless to say, I was not a happy bunny! Incidentally, even my entry-level control optic showed far less flaring and internal reflections than this purportedly “premium” instrument!

    As another control for these tests, I employed my most excellent Barr & Stroud Savannah 8 x 42, which shows remarkably little flare and diffusion of light under the same conditions. Indeed, as I already communicated in a previous blog, this superb instrument possesses the same level of glare and internal reflection control as a Swarovski EL Range 10 x 42 unit I recently subjected to the same tests. The reader will note however, that no roof prism binocular, no matter how well built it is, can completely eliminate such optical side effects.

    My control binocular for flare and internal reflection testing; the Barr & Stroud 8 x 42 wide angle, which delivers superbly contrasted images even in harsh lighting conditions.

    A curious aside: I wonder will flare and internal reflection testing suddenly enjoy an upsurge on future binocular forums? Hmmm.

    I suspect that many of these pocket binoculars are not tested for flaring and/or internal reflections because these small instruments are not recommended for night time use and so any problems they have in this regard might easily slip below the radar. I would check out your instrument to see how it fares in this regard.

    For me, a binocular, no matter how small it is, should pass these tests. Remember, we’re not looking for perfection here. If you’re viewing a city scape at night or gazing at the Moon from time to time, your pocket binocular should have minimum light leak and scatter, so that it does not show up in ordinary use. Is that really too much to ask for?

    I don’t think so!

    Verdict: The Bresser Pirsch 8 x 26 possesses excellent mechanical features but its optics do not match its mechanics. Not recommended. Luckily I had registered the instrument with Bresser to enable the terms of the guarantee to be fulfilled.

    So how did the Kowa SV 8 x 25 fare in comparison?

    Here is what the company promised.

    Well, the package I received came in a small box, containing the binoculars, instruction manual, carry strap and eyepiece caps but no objective covering caps. Unlike the Pirsch, the Kowa is double hinged, which enables you to fold the barrels under the bridge,. making it truly pocketable. You can get an idea of the transportable size difference of both the Pirsch and the Kowa by comparing the size of their carry cases;

    The carrying cases for the Pirsch(right) and Kowa binocular(left).

    My first impressions of the Kowa SV 8x 25mm binocular were favourable. It is small and rather cute looking. Kowa engineers deliberately designed the instrument to be very lightweight using modern materials. It has a very well armoured body with a tough, coarse- feeling rubberised exterior.

    The Kowa SV 8x 25 is a well made binocular using modern materials to reduce the weight. Like the Pirsch, the dioptre setting ring is under the right barrel.

    The eyecups twist up and down like the Pirsch  but appeared to have only two fixed settings; fully extended or retracted.  You can however, set the eycups at any position and they will hold their place.

    The Kowa glass had what seemed to be immaculately applied anti-reflection coatings on the eye lenses and objectives, which almost disappear when examined head on. Kowa also apply a hydrophobic coating on the elements that allegedly repels water, oil etc, making cleaning the exterior optics that little bit easier.

    The kowa ocular lenses have nice anti-reflection coatings. Note the smaller eye lenses on the instrument.

    And here is what the objectives look like under inspection. Kowa engineers applied extra armouring around the nicely recessed objectives for added protection.

    The objective lenses on the Kowa are nicely recessed and have immaculately applied anti-reflection coatings.

    The focuser is made of a soft material that effortlessly moves clockwise and anti-clockwise. I found that it was smooth and very responsive in use, with little in the way of stiction.

    A close-up of the Kowa focuser.

    Like the Pirsch, the instrument is fully waterproof and is nitrogen purged. The optics are fully multi-coated and a phase coating applied to the Schmidt-Pechan roof prisms. But at this stage in the game, I had learned not to place my hope in an instrument based solely on these claims. I recalled the story of the little Celestron Nature DX which also advertised such advanced optical treatments, but failed miserably in field use.

    Like the Pirsch, the Kowa barrels were well collimated and the field of view was found to be slightly smaller than the Pirsch, at just over 6 degrees. But when I began to assess the optics of the unit, I hit my first snag. The smaller eye lenses on the instrument made it very difficult for me to accurately position my eyes and I immediately noticed that I was frequently experiencing black outs as I moved from one daylight target to another. It did have better eye relief than the Pirsch though, allowing those who wear eyeglasses to use it fairly easily.

    Worse still, I noticed that when I was observing with the Kowa in bright daylight conditions outdoors, I could see a faint ghosting in the field which would only vanish when I pressed my eyes tightly against the eyecups. The contrast was noticeably better in the Kowa images though, with excellent control of colour and seidel aberrations. But I was worried about the ghosting I saw, and so decided to perform my iphone torch test to see what was what.

    Such testing revealed some problems. While the horrible diffused light I saw in the Pirsch was far better controlled(but nonetheless present), the test revealed a pretty bad case of on-axis flaring. My heart sunk as I contemplated the implications of the test. This would also show up in nightime test I told myself, and I waited until the evening to find out for sure.

    Turning the unit on a bright sodium lamp all too easily revealed a pretty bad dose of on-axis flaring which ruined the image. And though internal reflections were much better controlled in the Kowa than in the Pirsch, the flaring on bright nocturnal lights was, quite frankly, very annoying and downright unnaceptable. And yet again, my entry-level control binocular fared better than the prestigious Kowa in the same tests.

    I really hoped Kowa, a company which enjoys a strong reputation for precision, high-end  sport optics, would be able to deliver a binocular image without this degree of flaring, but  alas, it was not to be.

    Visibly upset, I contacted Kowa UK to report the result. They quickly responded and apologised to me for the fault, explaining that this was a very ” unusual” finding.

    Well maybe. But it didn’t stop me immediately packing up the instrument and its accessories and returning it to amazon. I received a full refund, but had no interest in  testing out a replacement unit. Once bitten twice shy.

    Note added in proof: Control of light leakages bares little correlation to the price paid for these binoculars. For instance, my Barr & Stroud 8 x 42 and 10 x 50 roofs have a retail value of about £130 and £80, respectively, but have excellent control of stray light. If these did so well, why couldn’t the little pocket binoculars deliver?

    Ich verstehe nicht.

    Another pretender:

    Same old same old: the Olympus 10 x 25 has the same optical design as the Kowa SV pocket binocular.

    What about the Olympus 10 x 25 WPII?  I took a chance on this product also. Retailing for about £70, it offered all the same features as the Kowa binocular. Indeed it was almost a carbon copy of the Kowa, except for the magnification and focus wheel, but alas it also showed too much daylight glare when pointed at brightly backlit objects, so that went straight back to amazon as well. Though sharp in the middle of its relatively massive field(6.5 angular degrees), the Olympus binocular showed very distorted images in the outer 30 per cent of the same portal. So, not great, either.

    An Old Reliable: It’s not all doom and gloom though. Compared with the three binoculars I had evaluated thus far in this blog, my wife’s Opticron LE Aspheric 8 x 25 pocket binocular is in a completely different league optically. With minimum flare, no blackouts and good control of internal reflections, the little classically styled Opticron is very well built and just works, time after time after time.

    A classically styled pocket binocular that just works; the Opticron LE Aspheric 8 x 25.

    Now a few years old, the Opticron LE Aspheric features multi-coated optics and silver- coated phase corrected prisms. Aspherical ocular lenses produce a very flat field that renders undistorted images right to the edge of the field. And though its field of view is a little restricted at 5.2 angular degrees, it’s a nice tidy portal with very well defined field stops.

    The Opticron Aspheric LE has simple twist up eyecups for those who do not use eyeglasses while observing.

    The eyecups have just two positions; up or down. With 21mm eye relief, the instrument is extremely comfortable to view through. The double-hinge design does allow the barrels to fold up to pocket size though;

    Snug as a bug in a rug.

    It has its own built in lanyard so there is no need to fiddle about attaching a neckstrap. The original Opticron Aspheric LE (with the green logo) is a bit on the urbane side though; it is not weatherproof and the outer armouring is smooth and non-texturised. But a few years back, Opticron gave this pocket binocular a bit of a makeover; the new Aspheric LE is waterproof and purged with dry nitrogen, making it that little bit more versatile than the first generation model. Eye relief is reduced to 16mm, which should still be plenty good for all users. It also has new eyecups and a  re-designed focuser. Details can be found here.

    Nice big(17mm) eye lenses on the Opticron Aspheric LE make for highly immersive views.

    The instrument is more expensive than the Pirsch and Kowa models though; ~£120. But that extra cost does buy you peace of mind, or so I’m led to believe.

    I”m going to order up the new model to determine how consistent the quality is. I will report back in a wee while to tell you how I get on with it.

    Watch this space!

    September 10 2019: Well the new Opticron pocket binocular arrived safely today. So, what was in the goodie box?

    The Opticron Aspheric LE WP 8 x 25 pocket binocular and its accessories.

    The binocular was purchased from Tring Astronomy Centre, and I elected to have it shipped to me via expedited 24 hour delivery. The cost, including postage, came in at £120. Like everything else I have received from Tring in the past, the product arrived in perfect nick. It was double boxed, witth the package including the pocket binocular, an instruction manual, lens cleaning cloth, and warranty card, and a stylish padded carry case with the Opticron logo on the front. I even received a £75  wine voucher!

    The New Opticron Aspheric LE is now water and fog proof.

    Unlike the original model, the make and specifications on the new model are embossed on the upper bridge. The armouring is also slightly more texturised than the sleeky, first generation model.

    The original model had plastic eyecups, but the newer incarnation has what appears to be a slightly more comfortable rubberised overcoat.

    Using the Optricon Aspheric LE WP is child’s play; just twist up the eyecups and they click into place. There are no intermediate settings. If you wear glasses, leave the eyecups down.

    I rather like the simplicity of the eyecups on this instrument. There are only two positions: fully extended or fully retracted. The 16mm eye relief is plenty good enough for eyeglass wearers(verified by my own tests).

    The focus wheel is larger and a little easier to work with than the original model.That will make it easier to use with gloves on. I did find it to be a wee bit on the stiff side though, but I figure with more use, it will became easier to negotiate.

    The newer Opticron Aspheric LE( right) has a slightly larger focusing wheel.

    The ocular lenses are the same on both models; good and large and easy to engage with.

    Both models have the same optics, including large ocular lens.

    The neoprene carry case is very nicely made and fits the pocket binocular perfectly:

    A very nicely fitting padded neoprene carry case will keep your optics safe while not in use.

    Close up of the Opticron labelled padded case.

    You can probably guess by now what I did first: yep, I performed my torch test to see how well stray light was being controlled inside the barrels. Well, it passed with flying colours; not perfect, but perfectly acceptable! Indeed, it was very similar to the results I obtained for the original model. Later, I performed a test on some sodium street lights and the results were very good. Only very slight ghosting and no annoying glare.

    What a relief!

    Conducting some observations during the day also delivered very pleasing results.The images are very bright, sharp and colour-pure, thanks to good quality glass, anti-reflection coatings and a silver mirror coating on the prisms. Like the original model, backlit scenes show excellent control of glare and certainly enough to satisfy the vast majority of users. The aspheric ocular lenses did a great job maintaining a very flat field nearly all the way to the field stop. Close focus was astonishing! I measured it at just 51 inches (~1.3m), so significantly less than the advertised 2 metres. A nice bonus!

    Clearly the quality control on these instruments appears to be very good indeed.

    Weighing in at just 291 grams, and with its double hinge design, folding it up and storing it in your pocket is a breeze. It’s nice to have a pocket binocular that does exactly what it says on the tin.

    Alas, I was unable to perform my last test on the bright Moon owing to the presence of a weather system (the remnants of hurricane Dorian) passing over Scotland, but the results on stray ligt control gives me no cause to be concerned. It will pass the full Moon test with flying colours!

    A quality pocket binocular in the palm of your hand!

    A Curious Aside: Here’s a binocular review posted on September 11 2019.

    Wow!

    The reviewer even conducted tests for glare and flaring etc!

    Shockeroonie!

    Don’t take my word for it; look at some other reviews of the Opticron Aspheric LE pocket binoculars to better establish a consensus:

    Calvin Jones, Irish author, birder and naturalist

    Diane and Michael Porter’s Birding Binoculars

    Feathersoptics review

     

    Conclusions and Lessons Learned:

    It is clear that good optical performance cannot be gleaned from checking the specifications of a pocket binocular. Claims of a product offering fully multicoated optics and phase corrected prisms etc count for nothing if they cannot suppress glare and internal reflections to an acceptable degree. In this blog I have sampled but a few models that fell short of my expectations. In the end, only the Opticron Aspheric LE 8 x 25 delivered the readies.

    The best way to proceed with acquiring a pocket binocular is to test it out in person, if at all possible, before handing over your hard-earned cash. The reader should also be leary of any binocular review that does not mention or test for glare, flare and internal reflection. This is an essential feature that must be controlled if you are to derive the best performance out of your pocket optics.

    Life’s too short to look through bad glass!

    Opticron also manufacture a series of more expensive pocket binoculars in their BGAT PC Oasis series. These will also be a good bet, but you’ll have to cough up another £100 to acquire one. I may test one of these models out in the future.

    I did consider a few ED models in my quest. For example, the Hawke Endurance ED 8x 25 has a wider field of view and retails for 20 per cent less than the Opticron(which has no ED glass), but is it as well built? And how do the optics fare? To be honest, I don’t know, as there wasn’t any discriminating reviews available for me to make a decision, but they might be worth a punt. I did contact Hawke asking them how well they suppress glare in their small pocket binocular and received a very quick reply. Here is a copy of my correspondence with the company:

    ……………………………………………………………………………………………………………………..

    Dear Sir/Madam
    I am writing to inquire about glare suppression and internal reflections in your Hawke Endurance 8x and 10x 25mm pocket binoculars.
    I have been testing a few brands and some show very annoying flare and/or ghosting when pointed at a bright street lamp or a bright Moon.
    Will your products pass such tests?
    I appreciate that no binocular can completely eliminate these but all I am asking for is no obvious ghosting when pointed at the moon or strongly backlit scenes in daylight.
    Thanks in advance of your reply.
    Sincerely
    Neil English.

    from: Hawke UK uk@hawkeoptics.com

    Hello Neil,

    Thanks for your email and interest in Hawke Optics. The internal components of our binoculars are treated to be as glare resistant as possible. We use a combination of matte finishes and ribbed surfaces to prevent a flat reflective surface. However, it will never be possible to completely eliminate reflections like you are talking about and so even with these countermeasures, our binoculars will show some white out when looking towards a bright light source.

    Kind regards,

    Alex Jenkinson

    ……………………………………………………………………………………………………………………………….

    I wonder if any of you have tested the Hawke model? If so, I’d be very keen to hear from you. Failing that, I might just go ahead and purchase one to do a full review; warts and all.

    I would also trust the optics in the Pentax AD bocket binocular, which also retails for about £100. But that’s not based on direct experience with this model, only an inference made from using two other binoculars from their line.

    For a few hundred pounds more you can acquire excellent pocket binoculars from the ultra-premium end of the market from Zeiss, Leica and Swarovski. However, I don’t think you’ll notice any big optical differences between the Opticron and these though. The value lies more in their mechanics than anything else.

    For me, I feel the Opticron delivers everything I could wish for in a pocket binocular; both mechanically and optically. It’s a quality product that will stand the test of time if looked after properly.

    Well, I hope you found this blog to be informative.

    Good luck with your quest to find a good pocket binocular!

     

    Neil English’s newest title, The ShortTube 80: A User’s Guide, hits the bookshelves in early November 2019.

    Post Scriptum: Shortly after local midnight on September 12 2019, I ventured outside to see if I could gain a glimpse of the bright and nearly full Moon, that had just past the meridian and about 17 degrees above the southerly horizon. I compared the Bresser Pirsch 8 x 26 to the Opticron Aspheric LE WP 8x 25. A brisk westerly breeze was blowing, quickly shifting the clouds over and then away from the Moon. During one such clear spell I pointed both instruments at its silvery white face and studied the images.

    Result: The Pirsch showed annoying glare and some obvious internal reflections in the field. The glare also brightened the backround sky around the Moon, reducing contrast. However, the Opticron unit showed no visible internal reflections and only slight flaring when the Moon was placed just outside the field. The backround sky around the Moon was much darker to boot, showing clearly superior image quality to the “premium” Pirsch.

     

    De Fideli.

    Caveat Emptor!

    As you may gather, I’ve taken a keen, active interest in testing out binoculars with an aim to providing my readers with good quality products that won’t break the bank. As part of that process, I needed a few entry-level models to compare and contrast them with other products purporting to provide better optical quality. In one transaction, I purchased an Eyeskey labelled 8 x 32 roof prism binocular on August 5 2019 from eBay. It was brand new and set me back £37.79, taking about two weeks to ship directly from China to my home in Scotland.

    Here is a photo of what I received:

    The Eyeskey Package.

    Here is a close-up photo of the Eyeskey binocular; the reader will note the texturing of the armoring and distinctive tripod adaptor cover

    The Eyeskey 8 x 32 roof prism binocular.

    Here is what it looks like from the ocular end:

    Note the plain 8 x 32 & Bak4 Prism labelling on the focus wheel.

    And here is a photo of the tethered rubber objective lens covers as well as the thumb indentations on the underside of the binocular:

    Note the tethered rubber objective covers and thumb indentations on the Eyeskey.

    After inspecting the Eyeskey binocular and its accessories, I recalled another binocular, marketed by a company called Avalonoptics.co.uk, which I had come across in a previous internet search.

    Here is Avalon’s 8 x 32 Mini HD binoculars( all images taken from their website):

    Avalon 8×32 Mini HD Binoculars BLACK

    Here is an image of the entire package:

    Here is an image of the writing on the focusing wheel:

    Note the thumb indentations on the under side of the barrels on the Avalon:

    And here is an image of the tethered objective covers on the Avalon:

     

    Next, I took a look at the specifications of both models.

    You can view the Avalon specs here

    And here are the Eyskey specs( source eBay):

    8561-8X32_01

    Both claim to be fully multicoated, are nitogen filled and fog proof, but there is no mention of a phase coating on either model.

    There is a few differences in the quoted specifications. The advertised field of view is 6.78 degrees for the Eyeskey and 6.9 degrees for the Avalon model; quite close. Eye relief is quoted as 18mm for the Eyeskey and 15mm for the Avalon, but these figures can often be incorrect or at least misleading(as I will explain in another up-and-coming binocular review). The Eyeskey has an advertised weight of 18.3 oz = 519 grams, whereas the Avalon has a quoted weight of 416 grams.

    Weight can also be misleading though, as it can vary according to whether you include the lens covers and strap etc.

    The boxes look pretty similar with just different logos on them, same goes for the neck strap and generic instruction sheet.

    Now for the price comparison:

    Eyeskey 8 x 32: £37.79

    Avalon 8 x 32 Mini HD: £119(recently discounted 20% from £149)

    Finally, have a look at this youtube presentation of the said Avalon Mini HD binocular here.

    Is the Eyskey 8 x 32 model worth the £37.79?

    I suppose for what you get it’s a bargain.

    But what about the Avalon?

    I’ll leave that up to you to decide!

    Caveat Emptor!

     

    Neil English debunks many telescopic myths in his new historical work, Chronicling the Golden Age of Astronomy.

     

    De Fideli.