A Brief Look at The New American Standard Bible (NASB).

The author’s copy of the NASB Bible(1995  edition).

Now I make known to you, brethren, the gospel which I preached to you, which also you received, in which also you stand, by which also you are saved, if you hold fast the word which I preached to you, unless you believed in vain.

For I delivered to you as of first importance what I also received, that Christ died for our sins according to the Scriptures,  and that He was buried, and that He was raised on the third day according to the Scriptures, and that He appeared to Cephas, then to the twelve. After that He appeared to more than five hundred brethren at one time, most of whom remain until now, but some have fallen asleep; then He appeared to James, then to all the apostles;  and last of all, as to one untimely born, He appeared to me also. For I am the least of the apostles, and not fit to be called an apostle, because I persecuted the church of God. But by the grace of God I am what I am, and His grace toward me did not prove vain; but I labored even more than all of them, yet not I, but the grace of God with me. Whether then it was I or they, so we preach and so you believed.

1 Corinthians 15:1-11

Today we are fortunate to have many excellent translations of the Holy Bible in English. The highly accurate New American Standard Bible (NASB) offers its readers great ways to enrich their knowledge of the inspired word of God, with a number of unique scholarly features that highlight the challenges of translation from the original tongues, as well as revealing how the New Testament comes alive when viewed through the lens of the Old Testament.

 

Tune in soon to find out more………………….

 

De Fideli.  

What I’m Reading.

Fighting the good fight.

Hardback: £27.99

Scientists love to tell stories about the quest to understand the universe-stories that often have profound implications for belief or disbelief in God. These accounts make their way into science textbooks and popular culture. But more often than not, the stories are nothing but myths. Unbelievable explodes seven of the most popular and pernicious myths about science and religion. Michael Newton Keas, a historian of science, lays out the facts to show how far the conventional wisdom departs from reality. He also shows how these myths have proliferated over the past four centuries and exert so much influence today. The seven myths, Keas shows, amount to little more than religion bashing-and especially Christianity bashing. Unbelievable reveals: Why the vastness of the universe does not deal a blow to religious belief in human significance. Why the “”Dark Ages”” never happened. Why “”Flat Earthers”” had basically disappeared by the third century B.C. Why the real story of Giordano Bruno’s life and death is far more complicated than the popular account of him as a martyr for science. What everyone gets wrong about Galileo, and why it matters today. Why the notion that Copernicus “”demoted”” humans from the center of the universe didn’t gain traction until centuries after his death. The futuristic myth that scientists and others are positioning to challenge religion. In debunking these myths, Keas shows that the real history is far more interesting than the common account of religion at war with science. This accessible and entertaining book lays out powerful arguments that will be embraced by religious believers tired of being portrayed as anti-intellectual and anti-science.

Some Reviews:

Unbelievable should be on the shelf of every science popularizer and college astronomy professor. Perhaps then we can begin to purge our culture of the ‘science is the enemy of religion’ myths Michael Keas slays in his refreshingly contrarian book.”
–Guillermo Gonzalez, Assistant Professor of Astronomy, Ball State University; coauthor of The Privileged Planet

“Not content to knock down the myths about the alleged conflict between science and religion, Mike Keas shows where they came from and how science popularizers like Carl Sagan have used them to further their own agendas. Using a wide range of sources, including textbooks and television shows, Keas explains how these myths got into the bloodstream of our culture. An invaluable resource.”
–James Hannam, author of God’s Philosophers and The Genesis of Science

“Michael Keas decisively debunks an array of myths that have long impeded our understanding of the histories of science and of religion. Unbelievable may earn Keas plenty of enemies, but nobody concerned with real evidence can dismiss his argument out of hand. This is a brilliant, engaging, and important contribution to a debate about truly universal matters.”
–Dennis Danielson, Professor Emeritus, University of British Columbia; editor of The Book of the Cosmos

“Michael Keas does a splendid job dispelling viral myths and common errors about the relationship between science and Christianity. This book is well documented and written in a pleasing style accessible to the general reader as well as scholars.”
–Jeffrey Burton Russell, Professor of History Emeritus, University of California, Santa Barbara; author of Inventing the Flat Earth

“The notion of inevitable, perpetual conflict between science and religion is one of the most prevalent grand narratives in the modern West. It takes many specific forms, and Michael Keas deftly disposes of myths like these with lively, thoroughly researched stories that will leave readers much better informed.”
–Edward B. Davis, coeditor of The Works of Robert Boyle

“The supposed warfare between science and Christianity has long been a staple of science textbooks and popular science. Michael Keas skewers the most popular myths used to illustrate that warfare, displaying his deep knowledge of the history of science. If you want to understand the true, and positive, relationship between science and Christianity, you should read Unbelievable.”
–Jay W. Richards, bestselling author of Infiltrated and Indivisible

 

De Fideli.

Chronicling the Golden Age of Astronomy: The Reviews are Coming In!

Honest Graft. No bull.

 

The Reviews and Comments on my latest work are now coming in:

 

Official British Astronomical Association(BAA) Review by Archivist, John Chuter

 

Cloudy Nights Review

 

Stargazer’s Lounge Review

 

 

Amazon Reviews:

650+ pages of well-written detailed technical and biographical. The myriad illustrations and photographs are superb quality. I’m still perusing; the kind of book you may want to skim for a month, before reading it cover-to-cover!

 

 

 

To Be Continued……………………….

 

De Fideli.

The Lockyer Sequence

New year’s Day 2019: Plotina starting well on a trail first blazed by Sir Norman Lockyer(1836-1920).

On the evening of January 1 2019, I set up my 130mm f/5 Newtonian astride its Vixen Porta II mount. Conditions were cold, still, and frosty, with temperatures between 0 C and -2C. Seeing was judged to be very good (Antoniadi II).

My purpose this evening was to examine a half dozen double and multiple stars in Orion, as suggested by the distinguished Romanian observer, Mircea Pteancu, who kindly alerted me to a reference made by Norman Lockyer et al in their book, Stargazing: past and present (1878). On page 164 of that book, the authors describe a sequence of double and muliple stars in Orion, which present systems of varying degrees of difficulty for the curious telescopist. After careful collimation and adequate acclimation, the 5.1″ reflector was turned toward the Celestial Hunter, beginning at about 22:00UT and the following systems examined at magnifications ranging from 118x to 566x. The results are shown below:

The Lockyer Sequence.

 

Notes:

The times and magnifications employed are displayed beside the drawings, which depict their orientation in the Newtonian reflector. For all sketches, south is up and west is to the left.

Teasing the close companion to Zeta Orionis apart from its brilliant primary did prove quite tricky, but with a concentrated gaze during the stiller moments, it did yield to the 130mm telescope. The reader will also note the much fainter(10th magnitude) shown at the lower right of the sketch.

The most challenging proved to be 52 Orionis(1″ separation), but with its decent altitude at 22: 43UT, I was able to resolve this classic Dawes pair ( twin 6th magnitude components)  using very high powers. Intriguingly, I first attempted this system by coupling a Meade 3x Barlow lens to a 4.8mm T1 Nagler yielding 405 diameters but without much success. The image was quite dim and very difficult to see the components distinctly. As an experiment, I switched to a Meade Series 5000 5.5mm ultra-wide angle ocular, coupling it to the same 3x Barlow but I also screwed in a 1.6x Astroengineering 1.6x amplifier yielding a power of 566x. To my great surprise, I found the image of the system to be significantly brighter than with the old Nagler and it was much easier to prize the components apart. I can only suggest that the better (read more modern) coatings on the Meade 5.5mm ultra-wide angle allowed greater light throughput, despite the higher powers employed.

566x represents a power of 111x per inch of aperture.

The 130mm f/5 Newtonian continues to surprise and delight me. It’s small, high-quality optics, thermally stable (cork-lined) closed-tube design, and ease of attaining perfect collimation all contribute to its efficacy as a medium-aperture double star instrument.

I would encourage others who have similar equipment to give these beautiful systems a visit. What better way to entertain and challenge a dedicated observer on a cold winter’s evening!

 

 

De Fideli.

A Tale of Three Binoculars

My 30-year old 7 x 50 binocular.

 

It was just over 30 years ago when I was gifted a nice 7 x 50 binocular by my girlfriend. They featured a 7 degree field, multi-coated optics and BaK-4 porro prisms. They served me well all these years on holidays, walks and for casual stargazing. They weren’t cheap either. Lesser units would have fallen apart by now, but after trying a few modern binoculars out I knew that technology had moved on, mostly for the better.

And so had my eyes.

Now that I’m older, I wanted a binocular that had an exit pupil more suited to my age. I wanted an instrument that was more light weight, so that I could observe for longer without using tripods. I wanted a binocular that would do well in a variety of situations, from nature watching from dawn to dusk, and for astronomy. They had to be robust and ideally weatherproof to a degree. My ideal binocular views had to serve up sharp, colour pure views of autumn’s radiant hues but also allow me to throw caution to the wind and just enjoy the glories of the night sky from the comfort of a recliner. But which ones to buy?

Alas, I found that choosing a model that ticked all the boxes for me to be a daunting prospect! Today, we have so many makes to choose from; which is a good thing. My experience with telescopes came in very handy though. Not easily swayed by marketing gimmicks and wishy-washy hyperbole, I slowly pared them down to size.

I decided I wanted a fairly compact, full-size binocular that would offer good light grasp, so a clear aperture of 42mm would be about the minimum that would do the trick. I wanted a fully multi-coated instrument to maximise light transmission to the eye and reduce glare on bright objects to an acceptable minimum. They had to be well made with a decent warranty should they get damaged or worn out from regular use. And they had to present good value for my hard-earned cash.

I narrowed my search down to a good roof-prism binocular as these had many of the features I was looking for; small, light weight, decent light grasp, ultraportable etc. Two magnifications were considered, 8x or 10x. With 10x you’d get a smaller exit pupil and lose some advantages of using them in low light conditions. 10x would also introduce more shake and would be more difficult to accurately focus while in use too, so I decided on 8x; an 8 x 42 binocular.

I went to amazon.co.uk to check out the user reviews of a variety of models I had an interest in. In many ways, these types of reviews give the prospective buyer a more rounded view of what it’s like to use a given model, as they are often more honest and less biased than those offered by so-called ‘experts,’ who, more often than not, succumb to clever marketing ploys and had a tendency to push premium products over more economical models that might still offer perfectly acceptable performance. I found that birders, for example, often highlighted a variety of mechanical and optical features that were largerly superfluous to my needs. I didn’t really need super-fast focusing, locked in dioptre settings, nor ED elements in the objectives. At such low powers, one would be hard pressed to see the advantages of employing low dispersion glass and most of the online literature seemed to over-emphasise their advantages even though I knew that it would only make a small (insignificant?) difference to the views. Afterall, how many amateur astronomers insist on having ED finder ‘scopes eh? Why haven’t 8 x 50 ED finders or some such become the industry standard, if they really offered any tangible advantage over good ole crown & flint? The honest answer is that they’re unnecessary, and so can be dispensed with.

As a case in point, check out this user review of the Vortex 10 x 42 Diamondback roof prism binocular. The gentleman states that he was asked to try out the more expensive Viper model with ED objective elements in a blind test. He states that he couldn’t really tell the difference in field use. I have no reason to doubt the gentleman’s conviction. Why lie on such a trivial matter?

No, a good, no-frills, traditional achromatic binocular to match my average eyes was what I was shopping for!

I went with a company that had a long track record of producing high quality optics, as I reasoned that such knowledge would be invaluable in the construction of a well-made binocular. Many companies selling such binoculars were not long in the game though, so my instinct was to avoid them. I gravitated toward an old British firm that had produced optics for the military in two world wars; Barr & Stroud.

Now bought out by OVL, Barr & Stroud  re-entered the sports optics market by bringing out a range of affordable roof prism binoculars in an 8 x 42 format and my first purchase was the Sahara 8 x 42, which retails for about £70-£90 UK.

The Barr & Stroud Sahara 8 x 42.

 

Though under no illusions that these are British made, Barr & Stroud binoculars are now assembled in China, just like those marketed by Vortex (a US-based company) and many other companies. They are supplied with a nice, soft carry case, neck straps, a lens cleaning cloth and have a 10-year warranty.

The Sahara 8 x 42 binocular comes in attractive box with a good carrying case with the usual accessories.

 

The specifications of the Sahara 8 x 42 model can be viewed here.

The Sahara is a joy to use. It’s small and light weight (670g), has good eye relief (17.5 mm) and with its twist up eyecups, will allow those who must wear eye glasses (I don’t) to enjoy the expansive field of view (7.33 angular degrees). Images are bright and sharp and colour fidelity is sound. With its fully multi-coated optics, contrast and glare suppression are excellent too in comparison to my old 7 x 50s. You really have to look for chromatic aberration but it is there. You can best see it by focusing on the edge of a telephone pole against a bright, overcast sky background, but is minimal and not in the least bit intrusive(I’d say mostly bum-fluff). At the edge of the field, the image gets a little softer with some slight fringing during daylight hours but it will never be enough to disturb the vast majority of users. Focusing is smooth and intuitive, not overly stiff or loose and it has an excellent close focus distance of just under 2m (measured) to allow you to enjoy insects, flowers etc at close range. It also has adequate waterproofing for my intended uses for it.

Night time views were very impressive too. Stars are sharp and pinpoint across the majority of the field. Only by using a stable tripod, will you be able to notice a little defocus of the stellar images at the edge of the field. All in, I would rate the Sahara as very good and considering its modest cost; a great bargain in today’s market! These guys certainly know how to make a good binocular!

Shortly after purchasing the Saharas, I began researching the properties of roof prisms and discovered that they have a significant design flaw. In the roof prism design, the two halves of the collected light from the objectives travel through the prism independently and are recombined before reaching the eyepieces. Because the path of the two wave trains are of slightly different lengths, one half of the light takes a little longer to travel through the prism than the other. When the two halves of the image are recombined, the wave with the longer light path will be slightly out of phase with the light that undergoes the shorter route. This results in a combination of destructive and constructive interference of the wave trains, affecting the colour balance, contrast and fidelity of the binocular image.

Note that this flaw does not affect porro-prism-based binoculars!

By introducing a special phase coating to the prism undergoing the shorter light path, optical designers can slightly retard the wave train, thereby correcting the phase difference with the other wave train. This results in sharper, brighter images with higher contrast; in theory. As I researched this some more, I discovered that the result was quantitatively significant; 8 per cent according to the manufacturers. Intrigued, I looked for a Barr & Stroud model that had this phase coating as the Sahara’s did not have this technology built in and that quickly led me to their 8 x 42 Sierra model.

The Barr & Stroud 8 x 42 Sierra binocular.

 

Luckily, the Sierra was only a little bit more expensive than the Sahara. Full specs here.

Otherwise sharing very similar specifications to the Sahara, the Sierra 8 x 42 is also slightly lighter (650g), coming with the same soft carry case and accessories as the former. The polycarbonate body was also a little different in the Sierra compared with the Sahara, as the above images show. When it arrived, the first thing I did was undergo a test to see if there was any significant difference between the images. Examining a brightly lit scene with a trunk of a tree shadowed by some over-hanging branches and comparing the two binocular images, I must admit that the Sierra was that little bit better. It’s difficult to describe in words but I suppose I’d say that the Sierra image had a little bit more ‘zing’ to it. The image was that little bit brighter and the colours more vivid. Contrast was also better by a shade.

Based on this test, I think phase coating technology is definitely worth having. Subsequent research of other high-end and mid-priced binoculars revealed that they all possessed these phase coatings. I see them as increasing the overall efficiency of light transmission, improving the image in a way that the human eye would notice in a critical test.

In another test comparing my 7 x 50s to the Sierra’s, I had to immediately concede that the images in the latter were far superior to the old porro prism binocular. The image was actually brighter even though it only had 42mm objectives(as opposed to 50mm in the auld yin) and the contrast far superior. The Sierra also presented a larger field of view.

Man and his technology!

Before describing my experiences with the Sierra 8 x 42 in any more detail, I was curious to see how the unit would fare compared with a high-end binocular with roughly the same specifications. As luck would have it, my coalman is a keen birder and dabbles in hunting big game. He’s the proud possessor of a Swarovksi EL 8.5 x 42 binocular, which retails for about £1800 UK. When he came to deliver some coal I got chatting with him and asked him if he would be so kind as to bring them by some afternoon so that we could compare and contrast the images garnered by these binoculars. He agreed.

The Swarovski EL 8.5 x 42 roof prism binocular.

 

Though certainly not a ‘gayponaut’ (a word of my own coining, fomally defined as: an irrational obsession with small ED optics), my coalman, Graham, bought his Swarovski’s about ten years ago, and I was glad to see that they looked as though they’d been used. When I asked him why he chose them he said, “they’re supposed to give brighter views in low light.”  I thought that answer was a little vague though. He didn’t seem to know anything about the fluorite element in the objectives, or the effects of coatings on the optics. He was simply won over by the advertising. I believe this is common among buyers of high-end optics. Afterall, you don’t need to know anything about an internal combustion engine in order to drive a car do you?

Indeed, I knew far more about his Swarovski’s than he did. Nevertheless, we compared the images. I got a shot of Graham’s 8.5 x 42s and he got a chance to test out my 8 x 42 Sierra’s. The results were interesting.

I felt the image quality was excellent in the Swarovski’s. It gave a slightly more neutral colour tone to the Sierra’s in a very slightly larger true field (7.6 angular degrees). Contrast was excellent with really first-rate definition. The built-in field flattening lenses in the eyepieces improved the edge of field correction, and the slight colour fringing I had tried hard to detect in my Sierras was invisible in the Swarovski’s.

Graham liked the Sierras too though. Indeed, he said to me that, ” they’re pretty much the same aren’t they?”

I found it hard not to disagree. I felt the images were much more similar than different.

But what I did appreciate were the mechanical attributes of Graham’s binocular. Its buttery smooth focusing wheel made it easy to adjust focus distance from about 4.5 feet to infinity very swiftly; a bonus for birders I guess. I also appreciated the wonderful diopter adjustment apparatus and hearing the ‘click’ as it was turned to the correct setting.  This clever diopter locking mechanism means that there’s little chance of it slipping out of place during field use. Great, but not something I couldn’t live without.

The Swarovski’s body is a very rugged magnesium alloy chassis which gives a feeling of reassurance while handling the optic, but I didn’t really understand how it would be more resistant to corrosion over the far less expensive polycarbonate body usually found on the majority of sports optics. What Graham and I did notice was the significant weight difference between the models. The Swarovski’s were nearly 200g heavier than the Sierra’s, something that would definitely have a bearing on observing comfort during prolonged field use.

The excellent life-time warranty on the Swarovski’s was something Graham appreciated. He told me that one of the caps on the ocular lens had worn out (they can actually be removed for easy cleaning of the eye lenses) but one of the company reps immediately fitted his unit with a new one; that’s great service!

In the end, I was very grateful to Graham for bringing by his high-end binocular. I was delighted to know that there wasn’t much in it optically. But then again, I kind of expected as much! Did the experience tempt me to save and invest in a Swarovski? I’d have to say no. My Sierra’s were plenty good enough, warts and all!

What to do with the Sahara’s? My sister- and brother-in-law love the great outdoors; camping, glamping, fly fishing, hill walking and sight seeing. The’ve never owned a decent binocular so these will serve as a suitable Christmas gift for them. I just know they’ll love it and use it!

As for the Barr & Stroud Sierra binocular, I will present a separate, in depth review of this instrument in another blog.

Thanks for reading!

 

Neil English is author of several books on amateur astronomy.

 

De Fideli.

Chronicling the Golden Age of Astronomy: A History of Visual Observing from Harriot to Moore.

 

This is an excellent book and will complement Ashbrook’s Astronomical Scrapbook and therefore have wide appeal to both amateur and professional astronomers.

Wayne Orchiston, Professor of Astrophysics, University of Southern Queensland, Australia.

 

Book Content:

Introduction & Acknowledgements

  1. Thomas Harriot, England’s First Telescopist
  2. The Legacy of Galileo
  3. The Chequered Career of Simon Marius
  4. The Era of Long Telescopes
  5. Workers of Speculum
  6. Charles Messier; the Ferret of Comets
  7. Thomas Jefferson and his Telescopic Forays
  8. The Herschel Legacy
  9. Thinking Big: The Pioneers of Parsonstown
  10. The Astronomical Adventures of William Lassell
  11. Friedrich W. Bessel: The Man who Dared to Measure
  12. W.H Smyth: The Admirable Admiral
  13. The Stellar Contributions of Wilhelm von Struve
  14. The Eagle-Eyed Reverend William Rutter Dawes
  15. The Telescopes of the Reverend Thomas William Webb
  16. The Astronomical Adventures of the Artistic Nathaniel Everett Green
  17. Edward Emerson Barnard, the Early Years
  18. William F. Denning; a Biographical Sketch
  19. A Modern Commentary on W.F. Denning’s “Telescopic Work for Starlight Evenings (1891)”
  20. The Astronomical Legacy of Asaph Hall
  21. The Life and Work of Charles Grover(1842-1921)
  22. Angelo Secchi; Father of Modern Astrophysics
  23. John Birmingham, T.H.E.C Espin and the Search for Red Stars
  24. A Historic Clark Receives a New Lease of Life
  25. A Short Commentary on Percival Lowell’s “Mars as the Abode of Life”
  26. The Great Meudon Refractor
  27. A Short Commentary of R.G. Aitken’s “The Binary Stars”
  28. S.W. Burnham; a Life Behind the Eyepiece
  29. Voyage to the Panets: The Astronomical Forays of Arthur Stanley Williams( 1861-1938)
  30. Explorer of the Planets: The Contributions of the Reverend T.E.R. Philips
  31. Highlights from the Life of Leslie C. Peltier
  32. Clyde W. Tombaugh; Discoverer of Pluto
  33. A Short Commentary on Walter Scott Houston’s “Deep Sky Wonders”
  34. A Short Commentary on David H. Levy’s  “The Quest for Comets”
  35. George Alcock and the Historic Ross Refractor
  36. What Happened to Robert Burnham Junior?
  37. The Impact of Mount Wilson’s 60-inch Reflector.
  38. Seeing Saturnian Spots
  39. John Dobson and His Revolution
  40. The Telescopes of Sir Patrick Moore (1923-2012)
  41. A Gift of a Telescope: The Japan 400 Project

Appendix:

Achievements of the Classical Refractor: A Timeline

Index

 

Available now for pre-order!

 

Thankyou for waiting!

 

De Fideli.

De Rerum Natura

Hubble deep Field Image. Credit: Wiki Commons.

 

However, the Most High does not dwell in temples made with hands, as the prophet says:

 ‘Heaven is My throne,
And earth is My footstool.
What house will you build for Me? says the Lord,
Or what is the place of My rest?
Has My hand not made all these things?’

                                                                                         Acts 7:48-50

 

A new paper by a team of Oxford University scientists, submitted to the Royal Society, London:

Dissolving the Fermi Paradox

(Submitted on 6 Jun 2018)

The Fermi paradox is the conflict between an expectation of a high {\em ex ante} probability of intelligent life elsewhere in the universe and the apparently lifeless universe we in fact observe. The expectation that the universe should be teeming with intelligent life is linked to models like the Drake equation, which suggest that even if the probability of intelligent life developing at a given site is small, the sheer multitude of possible sites should nonetheless yield a large number of potentially observable civilizations. We show that this conflict arises from the use of Drake-like equations, which implicitly assume certainty regarding highly uncertain parameters. We examine these parameters, incorporating models of chemical and genetic transitions on paths to the origin of life, and show that extant scientific knowledge corresponds to uncertainties that span multiple orders of magnitude. This makes a stark difference. When the model is recast to represent realistic distributions of uncertainty, we find a substantial {\em ex ante} probability of there being no other intelligent life in our observable universe, and thus that there should be little surprise when we fail to detect any signs of it. This result dissolves the Fermi paradox, and in doing so removes any need to invoke speculative mechanisms by which civilizations would inevitably fail to have observable effects upon the universe.

Full Paper here

 

 

De Fideli.

Collins Stars & Planets (5th Edition): Book Review.

The new edition ( October 2017) of a favourite observing guide.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Collins Stars & Planets (5th Edition, October 2017)

Publisher: William Collins

Authors: Ian Ridpath & Wil Tirion

ISBN: 978 000 823927 5

Book size: 400 pages

Retail Price: £19.99 (UK)

The urge to study the sky transcends national boundaries, and so it should. The skies are open to us all.

pp 2

It’s been ten long years since I last purchased my field guide to the stars: Ian Ridpath & Wil Tirion’s 3rd edition of Stars & Planets. Travelling with me the length and breadth of the country and also on a few overseas trips, this pocket sized guide has proven indispensable for my grab and go excursions under the night sky. Alas, the wear and tear over the last decade is now definitely showing. The binding has now come loose and the pages have become heavily soiled from excessive handling. So, I figured it was high time that I got a new copy of this well received volume, and was delighted to see that it was now in its 5th edition (October 2017).

Stars & Planets is the result of a fruitful collaboration between the British amateur astronomer, Ian Ridpath, and an illustrator, Wil Tirion, living in Holland. In keeping with earlier editions, the first two thirds of the work consists of comprehensive maps of the night sky (both northern and southern hemispheres being readily presented) as they appear from month to month. In addition you will find fairly simple maps of all 88 constellations that grace the night sky, together with a list of interesting objects; some brief mythology, as well as notes on their brightest stars and deep sky objects within reach of a small backyard telescope. The full panoply of celestial objects are represented, including  a suite of pretty double stars, open clusters, emission nebulae, globular clusters, the brighter galaxies and planetary nebulae.  What particularly attracted me to the earlier edition was the relative simplicity of the maps; they were clearly designed to be used in the field where they present the basic outline of each constellation, as seen with the naked eye from a reasonably dark country sky. This enables one to easily ‘star hop’ from one object to the next. Striking a balance between adequate content and clear presentation, it is ideally suited to casual observing, adopting a low tech (my particular favourite) approach.

Each constellation shows the main deep sky objects accessible to an observer with a small, backyard telescope or binoculars.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I was delighted to see that the latest edition retained this same format, only that the maps are now presented with noticeably better contrast against a darker blue sky background. The introduction is filled with basic but very comprehensible facts to help you make sense of how the sky ‘works,’ as well as providing excellent notes on star names (both common and the Greek lettering system), how the planets move in the sky as well as such interesting topics as precession of the equinoxes. The final one third of the book covers information on practical astronomy, including a no frills overview of telescopes and binoculars, observing double and variable stars, comets and meteorites, the Sun, and the planets, including a brief overview of sky transparency and astronomical seeing. Here you will also find a very well laid out section on lunar observing, with plainly presented maps of the particular lunar sections that can observed as it grows from a thin crescent through to full Moon.

Overall, the content is ideally suited to those having small telescopes (60mm to 100mm aperture) and binoculars, with virtually all the objects being well seen with a telescope of just 6 to 8 inches in aperture. The volume is handsomely illustrated throughout, with very high quality images of a wide variety of heavenly bodies; both in the solar system and far beyond. While these are strictly not necessary in a field guide, they certainly improve the overall attractiveness of the book. My only criticism of the work is that the binding is the same as in earlier editions, and so will surely come loose with extensive handling. It would have been better to produce this with a simple ring or sewn binding for greater durability in the field.

For busy grab ‘n’ go observers.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Overall, I highly recommend this book as a conveniently small (for travel) but excellent field guide to the night sky that will be appreciated by either novices or seasoned observers alike. It’s strength lies with its simplicity and will keep a busy amateur happy for many years.

 

 

Neil English’s ambitious new historical work, Chronicling the Golden Age of Astronomy, will be publised later this year.

 

 

De Fideli.

Changing Culture III: Aperture & Resolution.

On the left, a 90mm apochromatic refractor and on the right, a 203mm f/6 reflector enjoying a bout of late evening sunshine.

On the left, a 90mm apochromatic refractor and on the right, a 203mm f/6 Newtonian reflector enjoying a spell of late evening sunshine.

 

 

 

 

 

 

 

 

 

 

Introduction:

One of the ABCs of telescopic optics is that resolving power scales linearly with aperture and light gathering power with the square of aperture. These are fundamental facts that are demonstrably true and have been used productively over two centuries of scientific applications. And yet, all the while, there has been a consistent drive in the last few decades within a section of the amateur community that somewhat erroneously links performance to absolute monetary value. This largely corrupt movement is most ostensibly seen in the refractor market, where amateurs are apparently willing to shell out relatively large sums of money for telescopes that, in terms of performance, are severely limited by their small apertures. This is a worrying trend indeed, and has led many astray within the hobby.

In this capacity, I decided to highlight the anomaly by devising a simple test which exposes this ‘peashooter’ mentality for what it is; a gross misrepresentation of basic optical principles.

Materials & Methods:

Two telescopes were set up in my back garden; a 90mm apochromatic refractor retailing at £1017 (tube assembly only) and a 203mm f/6 Dobsonian, with a retail price of £289, but with some basic modifications (97% reflectivity coatings and a smaller secondary giving a linear obstruction of just 22 per cent) which increased its cost to  approximately half that of the smaller telescope. The Newtonian was carefully collimated before use.

The telescopes were left out in the open air during a dry and bright evening when the temperatures had stabilised and were fully acclimated. Both instruments were kept out of direct sunlight. The refractor had an extendable dew shield to cut down on ambient glare, while the Newtonian was fitted with a flexible dew shield to serve the same purpose. To remove the complicating effects of atmospheric seeing, the telescopes were targeted on the leaves of the topmost boughs of a horse chestnut tree, located about 100 yards away.

Both telescopes were charged with approximately the same magnifications, in this case, a very high power was deliberately chosen; 320x. Next, the images of the leaves were examined visually, being especially careful to achieve the best possible focus, and the results noted.

Results:

The 203mm Newtonian images of the leaves were crisp, bright and full of high contrast detail. In comparison, the image served up by the refractor was much dimmer and a great deal of fine detail seen in the larger instrument was either ill-discerned or completely invisible in the smaller instrument. Though less dramatic, the same results were obtained when a larger refractor (127mm f/12) was compared with the 203mm f/6 Newtonian under similar conditions, with the latter delivering brighter, crisper images with finer detail.

Conclusions:

This simple experiment, requiring nothing more than a few minutes of one’s time and no complicated formulae or optical testing devices, clearly showed the considerable benefits of larger aperture. The images served up by the Newtonian were brighter and easier to see than those served up by the smaller instrument. Resolving power and light gathering power work hand in hand; you need decent light grasp to discern fine details and vice versa.These results were largely independent of the surrounding atmospheric conditions, as the targets were located at close proximity to the telescopes and thus had to travel through a short column of air.

These experiments were repeated with larger instruments; a 127mm f/12 refractor and the same 203mm Newtonian, with the same results, that is, the smaller instrument runs out of light faster than the larger and shows less fine detail in the images served up.

These results confirm that larger aperture is superior to smaller aperture. No amount of claptrap can change the result either. Complications may arise when the same tests are performed on celestial targets, especially during bouts of turbulent atmospheric seeing, when the larger instrument will be commensurately more sensitive. In such instances, it is the environment that introduces anomalies. But when conditions are good, the benefits of larger aperture will be seen, clearly and unambiguously. Absolute monetary value has little or nothing to do with the end result, in direct contradistinction to what is claimed by those who promote small aperture refractors in an unscientific way.

See here for further reading.

 

De Fideli

Changing Culture.

Octavius: instrument of change.

Octavius: instrument of change.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

As  I have commented on in previous communications, an urban myth has been cultivated over the years regarding the unsuitability of Newtonian reflectors in the pursuit of double stars. In the last six months or so, there are encouraging signs that more people are bucking this trend using Newtonian optics of various f ratios and in the examination of pairs of various difficulty, including the sub-arc second realm;

Exhibit A

Exhibit B

Exhibit C

Exhibit D

Exhibit E

These are but a few examples, and I can only hope that the changes will continue so that more people can enjoy this wonderful pass-time.

De Fideli