Tales from the Golden Age: A Short Commentary on Walter Scott Houston’s “Deep Sky Wonders” Part II

A Distillation of observing notes from the late Walter Scott Houston(1912–93)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Chapter 8: August (continued)

Summer lies hot and tranquil on the land. The gigantic storms of winter and the turbulent atmosphere that accompanies them are only memories now. At this time of year the seeing is steady all night.

West of the Meridian in late evening lie the great star fields dancing with the brilliance of Sagittarius, Scorpius and Scutum. The eastern sky, however, is a virtual desert of bright stars. The Great Square of Pegasus has little to offer the naked eye observer, and Equuleus is likewise dim. On nights when a bright Moon floods the heavens with its golden light, the eastern sky appears almost devoid of stars. Near the meridian, however, in the small constellation of Delphinus the Dolphin.

pp 187

I can almost imagine Scotty setiing up at sunset, his charts in one hand, his tobacco pipe in the other, pensive, waiting for the curtain of darkness to draw on the landscape. August is a very special time in my own seasonal viewing, as it represents the end of a long period of summer twilight, when the sky never becomes truly dark. Running from late May to the end of July, year in, year out, the arrival of true darkness in early August is an event to be celebrated!

As Scotty mentions, the summer months generally bring the best seeing in the year, and that’s true across many areas of Europe too, despite the encroach of biting insects; Scotty had the mosquito, here it is the midge fly. Despite its diminutive size, Delphinus offers a fair amount of deep sky real estate for the enthusiastic star gazer and Scotty does a sterling job highlighting them for his readership.

Scotty says that he developed a “fondness” for Delphinus because of its richness in variable stars, which he enthusiastically monitored in the early days of his work for the AAVSO. On page 188 he points out that the constellation is home to a number of very fetching double stars that are accessible with binoculars or a small telescope. Arguably the most celebrated is Gamma Delphini, which marks the northeastern corner of the Dolphin. Through my 80mm f/5 achromatic telescope it is easily resolved at 50x showing a lovely golden primary and pale yellow secondary separated by about 12″ of dark sky.  Scotty says they’ve hardly moved since the system was first surveyed in 1830 by Wilhelm Struve.

Houston also mentions the much more challenging binary system; Beta Delphini ( magnitudes 4.0 and 4.9)  the secondary of which exhibits an apastron of 0.6″ and periastron of 0.2.” This system was first discovered by S.W Burnham in August 1873 using his 6 inch Clark refractor. Scotty informs us that Burnham was lucky enough to examine the stars near their maximum separation. Then on page 189 he delivers another invaluable account of his own efforts to resolve this pair using his old Newtonian;

In 1950 I examined the star with my newly completed 10 inch reflector. Then the separation was near a maximum of 0.6″ with the companion due north of the primary. My first attempts to split the pair failed because the companion was lost in the diffraction spike caused by the telescope’s secondary mirror holder. Success came only after rotating the tube 45 degrees in its cradle to shift the position of the spike.

pp 189.

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Author’s note: I have spent the past few years carefully studying the properties of Newtonian reflectors in regard to their ability to split double stars. My findings showed that they were excellent instruments in pursuing this high resolution work, which has been traditionally associated with equatorially mounted classical refractors, and more recently in the promotion of very expensive apochromatic refractors. My own instrument of choice in the divination of difficult double stars, including sub arc second pairs is a 20.4cm f/6 Dobsonian (affectionately called ‘Octavius’) with a 22 per cent central obstruction. This work has instilled in me a deep respect for these telescopes that I am eager to share with my peers across the world. I give thanks both to Scotty and to Stephen James O’ Meara for including this material from his old Sky & Telescope columns and this book, respectively.

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Octavius; the author’s tried and trusted 8″ f/6 Newtonian on its ‘pushto’ mount.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Delphinus is also home to a number of rather lacklustre deep space objects. A challenge for larger apertures is provided with the tiny, compact globular cluster NGC 7006 (magnitude10.5), found by panning some 3.5 degrees east of Gamma Delphini. In my 8 inch telescope, NGC 7006 remains unresolved at 200x; more like a fuzzy snowball than anything else. Indeed, Scotty maintains that it remains unresolved in all but the largest instruments, and I would tend to agree. The reason is the enormous distance of this globular; now estimated to be about 140,000 light years (Scotty quotes 110,000 light years).

In the last couple of pages, Houston  discusses a few other objects of note in Delphinus, including the globular cluster, NGC 6934, the planetary nebula, NGC 6905, and the galaxy, NGC 6956. What is noteworthy is that Scotty weaves the experiences of other observers into his narrative, including Barbara Wilson, Philip Harrington, as well as celebrated authorities from yesteryear, such as the Reverend T.W. Webb (see pages 190 through 191).

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Chapter 9: September

Scotty begins this month’s adventures in the oft overlooked constellation of Lacerta, the Lizard. Sandwiched between the larger constellations of Cynus to its west and Pegasus to its east, Lacerta is one of the ‘new’ constellations introduced by Johannes Hevelius in 1687. Scotty suggests we shouldn’t overlook Lacerta owing to the fact that since 1910, three novae have blazed forth from within its borders, so who knows when the next one will come.  First up, Scotty draws our attention a very picturesque open cluster of stars for binoculars or small telescopes; NGC 7243. You’ll find this cluster a little over 2.5 degrees west of Lacerta’s brightest luminary, Alpha Lacertae. Here’s how Scotty describes this cluster:

The cluster stands out especially well from the stellar background when I stop down my 4 inch Clark refractor down to 1.8 inches. According to Revue de constellations by R. Sagot and Jean Texereau, NGC 7243 in a 4 inch at about 50x is a rich traingular cluster of many stars between 9th and 11 th magnitude. The number of stars increases from about 15 in a 2 inch to 60 in an 8 inch. I found no define shape in a 12 inch recently, but counted at least 80 stars within a 1/3 of a degree area. Look for a wide double at the luster’s center, particularly if you have a 6 inch or larger telescope.

pp 197.

The surprisingly rich open cluster, NGC 7243, in Lacerta.

 

 

Author’s note: This cluster is indeed a fine sight in 15 x 70 binoculars or a small telescope. My 80mm f/5 telescope reveals about 30 members at 50x, but nearly double that in my 8 inch reflector. Larger telescopes show more, growing to well over 100 in a 12 inch instrument, though the precise number also depends on the magnifications employed. Best to experiment with NGC 7243 to see what’s what.

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4 degrees directly south of NGC 7243 is NGC 7209, described on the bottom of page 197 and 198.

At midnorthern latitudes, the grand constellation of Cygnus rises high in the sky for exploration during September. On pages 200 to 210, Twinky covers much of its rich cache of deep sky treasures. After providing some interesting background on the constellation, Scotty launches into a wonderful discussion on the North American Nebula (NGC 7000), an enormous emission nebula located about three degrees east of the bright summer star, Deneb.

The huge and sprawling North American Nebula ( NGC 7000); a visble and infrared presentation. Image credit: Wiki Commons.

 

 

From my location, the skies are just dark enough to enable me to see the brightest parts of this emission nebula without the aid of a nebular filter. With a 32mm Plossl eyepiece delivering the large true field possible with a 1.25″ ocular, my 80mmf/5 achromatic delivers a wonderful field some 4 degrees wide at 13x. Scotty points out that NGC 7000 is an object celebrated more in modern times than in the past (see page 202). He attributes this to the rather restricted fields of the best telescopes of yesteryear, which tended to have very long focal lengths and the relative paucity of good, wide angle eyepieces. Indeed, in the darkest skies that Britain can offer, you can indeed make out the North American Nebula with the naked eye. Indeed, I last observed NGC 7000 in August of 2016 during a trip to the remote island of Skye, off the northwest coast of Scotland.

From here, Scotty moves on to M39, a nice open cluster for binoculars or small telescopes right up at the northern end of the constellation. To see it, centre your telescope on 4th magnitude, Rho Cygni, and move a little under 3 degrees further north, where it will appear in your low power telescopic field. Covering an area about half a degree wide, my tiny 3.1 glass at 13x reveals about twenty members, scattered haphazardly across the field. Scotty says he noticed a dark streak running about 5 dgrees east southeastward  from M39. A dark dust lane? What do you think?

Messier 39 in northern Cygnus; a nice binocular and/or small telescope object.Image credit:Wiki Commons.

In discussing dark lanes and nebulosity, Scotty mentions something very curious at the top of page 203:

The detection of dark nebulosity depends on many factors. I lean toward using long focus instruments because my experience has shown that they tend to scatter less light and provide a higher contrast image than do rich field telescopes. I have had some dramatic views of dark objects with my old 10 inch f/8.5 Newtonian reflector and the 12 inch f/17 Porter turret telescope in Springfield, Vermont.

pp 203.

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Author’s note: If you actually read through the book, you’ll notice that Scotty also makes the same claims for the images served up by his 4″ f/15 Clark refractor.The common denominator, so far as I can see, is the long native focal length of both his aforementioned  reflecting telescope and the classical achromat. Cassegrain and compound (catadioptric) telescopes don’t really count, as the primary mirrors are quite fast (typically  f/2 to f/4). The latter’s high net f ratio relies on the magnifying effects of the secondary mirrors.

What do you think?

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Pages 204 through 208 covers the weird and wonderful Veil Nebula in Cygus, an ancient supernova remnant which occured 15,000 years ago. Scotty describes it thus:

…..a broken bubble of luminous gas some 2 degrees in diameter. Although ignored by generations of telescope users, in the past 30 years the veil has progressed from a difficult test object to a reasonable target for anything from binoculars to the largest amateur telescopes. It is an excellent nebula for trainig the eye, perhaps the most important observing ” accessory,” to help us get the most out of the telescope we are using.

pp 205

Scotty informs us that the brightest parts of the nebula were discovered by Sir William Herschel back in 1784 during one of his sweeps using his homemade 18.25 inch speculum.  The Veil is partitioned into two distinct regions, east and west, with the former (NGC 6992) being slightly more easy to see. The eastern Veil (NGC 6992 & 6995) is found about 2.7 degrees northeast of the star 52 Cygni (an excellent colour constrast double for small telescopes). The western segment (NGC 6960) can be detected snaking its way past 52 Cygni. Getting to the spot in the sky where the Veil is located is the easy part but seeing it is quite a different matter! You’ll need very dark and transparent skies to have the best chance of seeing it with a backyard ‘scope without a nebular filter.

On page 206 Scotty raises the very interesting observation that it was hardly mentioned by the great amateur astronomers of the 19th century, even though their telescopes were certainly capable of detecting it.

Your chances of seeing the Veil nebula increase dramatically as the aperture of your telescope increases, but you can get very good results using an 8 or 10 inch telescope and a OIII filter. To see the individual strands with the structure a medium power should be selected (80x or 100x works well). Filters can work with smaller telescopes too, provided the magnification is not pushed too high. Below is a sketch I made a few years back of the eastern Veil using my 80mm f/5 achromat at 20x,with a 1.25″ OIII filter attached.

NGC 6992/95 as sketched with a 80mm f/5 refractor, x 20 & OIII filter.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Though he doesn’t mention them much, Houston describes his 5 inch binoculars on page 208. Earlier in the text, he does say that they were hobbled together from two Apogee 5 inch x 20 richfield refractors:

My Japanese 5 inch binoculars, though very heavy, originally had only a shaky tripod. I remounted them on a 3 inch pipe held in concrete down to the bedrock that is Connecticut. A well greased flange allows motion in azimuth while the altitude motion is provided by the binoculars’ built in trunions. Though makeshift, the mounting is granite steady and turns smoothly.

pp 208

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Author’s note: This is ‘vintage’ Scotty; making do with simple, no frills setups to maximise the time spent observing! Inspirational or what!

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On pages 208 through 210, Scotty shifts gear and dicusses the curious case of NGC 6811, a small open cluster located just under 3 degrees northwest of the challenging double star, Delta Cygni. Though his own notes recorded it as rather lacklustre; he received a curious letter from an amateur based in Denmark;

Several years ago I received a letter from Tommy Christensen, who lived in Odensa, Denmark, and observes with a 3.5 inch refractor. Along with a description of M33 and the Veil Nebula was a brief note about the open star cluster NGC 6811 in Cygnus. He called it one of the most beautiful clusters he had seen and mentioned a ‘ dark band about 5’ thick running through the middle of the cluster, not completely without stars, but nevertheless conspicuously dark.”

pp 209.

Scotty solicited comments from his army of fans, deliberately keeping his question about NGC 6811 vague.  Some of the responses he got were hilarious (you can read them for yourself on page 209), but quite a few folk did notice such a dark lane.

His conclusion was right on the money though:

This is a beautiful, albeit minor example of how people see things differently. Everyone was looking at the same cluster, but because of experience, conviction, or psychological factors, each saw it in a different way.

pp 209

The remainder of this chapter covering the September sky is devoted to Aquila, the celestial Eagle. On page 213, Scotty mentions our very own Rob Moseley (who kindly chimed in to this website a while back confirming the prowess of the Orion/Skywatcher 180 Maksutov in regard to its ability to resolve double stars) who wrote Scotty concerning the planetary nebula, NGC 6804;

One of the great pleasures of deep sky observing is the individuality that certain objects acquire in the eyepiece. I’m always delighted to learn that someone sees an object in a new perspective. One such example is Robert Moseley of Coventry, England, who tracked down NGC 6804 while testing a new 10 inch f/6 reflector. His best view was at 120x. He writes,” It gives the impression of a highly condensed but partially resolved cluster. It is a faintish oval nebulosity with a 12th magnitude star near its northeastern edge. With averted vision at least one other star could be seen superimposed upon it.” Moseley questioned the 13th magnitude I had given for NGC 6804 in an earlier column. Published magnitudes for planetary nebulae cause many disagreements, and I believe it is best to slightly mistrust all of them and to record your own magnitude estimates with your notes.

pp 213.

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Author’s note: Well done Rob! A fine addition to a fine book!

I like Scotty’s attitude to estimating magnitudes. What’s all the fuss about?

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Chapter 10: October

October is a most auspicious month for amateur astronomers. The summer haze and humidity have given way to cooler days and crisp, clear skies at night. darkness comes earlier, dewing of the telescope’s optics is generally less of a problem, and the sky is not do jammed with star clouds that confusion rules.

The Milky Way stretches from east to west across the northern star patterns, but here we are looking in the direction approximately away from the center of the galaxy. Star swarms marking the galaxy’s plane are thinner, and it is easy to star hop and make finder searches for objects embedded within them. Some of the most beautiful sights for small telescopes are in and around this corner of the Milky Way.

pp 217

October is indeed a wonderful month to be out of doors. The leaves of decidous trees shut down their chlorophyll factories, revealing the aureal tints of their secondary pigments. Nights are pleasantly long and temperatures remain mild for the most part. The great Square of Pegasus and Andromeda, the Chained Lady, loom large nearly overhead, ripe for exploration with binoculars and telescopes. And it is here that Scotty begins his adventures.

Beginning with the Square of Pegasus itself, Scotty asks a simple question requiring nothing from his readers except their naked eyes. How many stars can you count within the confines of the Square?

If you can see 13 you are reaching magnitude six.

pp 218

On the next page he follows this up with another question. How many deep sky objects are visible in Pegasus? The answer to this question depends on how acute your vision is but also on the size of the telescope you observe with. And it is here that Scotty reflects on the growth of telescopic aperture in comparison to earlier times:

Telescopes of 17 inch aperture are now off the shelf items of modest cost. There are a dozen or more amateur groups in the United States that either now have or are completing instruments with apertures of 24 inches or more. Such light gathering power brings within reach of the backyard observer virtually every deep sky object in the NGC and IC compilations. Thus the Great Square of Pegasus alone contains more than 100 suitable objects.

pp 219

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Author’s note: Scotty is referring here to the Dobsonian Revolution that swept the amateur world by storm in the last quarter of the 20th century. The Newtonian reigns supreme! As I explained in my book, Choosing and Using a Dobsonian Telescope, this was a true revolution and the only one that has occurred in amateur astronomy in living memory. And it’s gone from strength to strength; now amateurs are using fast 30 inch + behemoths for very reasonable cash investments, and which breakdown into convenient packages that can fit in an average sized car.

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The first deep sky object visited is 12th magnitude NGC 7479, found by panning just shy of 3 degrees due south of Alpha Pegasi, which marks the southwestern (Scotty mistakenly quotes southeastern pp 219) corner of the square;

The magnificent barred spiral galaxy, NGC 7479 in Pegasus. Image credit: ESA/NASA

If your eye is properly dark adapted, the galaxy should be visible in even a 3 inch telescope, but a 6 inch is better. A cloth over your head and the eyepiece gives you good protection from stray light. I have seen it easily with my 4 inch Clark refractor, but with small an instrument it is not possible to see any detail. On the otherhand the 12 inch f/17 Porter turret telescope at Stellafane in Springfield, Vermont, offers a more interesting view. At 300x the central bar is obvious and there is a hint of a spiral arm at one end.

pp 219/20

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Author’s note: My 8 inch reflector at 60x can make out the galaxy’s bright core, but the spiral arms do not yield at any power. Caldwell 44 needs a big gun to do it justice!

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Time and time again, Scotty affirms that high f ratio ‘scopes appear to do better than those of low f ratio, but is careful not to jump to any firm conclusions;

A 12 inch f/5 reflector set up near the Porter telescope did not offer as good a view of NGC 7479 even though I thought the mirror was good.It may have something to do with the longer focal length of the Porter telescope, or a better eyepiece. The importance of fine quality eyepieces has been overlooked by many amateurs…..Objects once considered only within reach of large amateur instruments are being seen in smaller telescopes equipped with fine eyepieces.

pp 220

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Author’s note: This is a can of worms! Don’t go there Scotty!

Longer focal length mirrors have less geometrical aberrations than their shorter focal length counterparts. That’s why we have coma correctors, for example! The former also hold their collimation better. That’s one of the principal reasons why I have called for the introduction of a mass market 8 or 10 inch f/7 Newtonian. Eyepiece quality is important too, as Houston points out. But we live in wonderful times nowadays. Eyepieces of higher quality than arguably the best in Scotty’s day are now available at very reasonable prices.

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On pages 222 through 226, Scotty sojourns to two celebrated globular clusters adorning the autumn sky; Messier 15 in Pegasus and Messier 2 down in Aquarius.

Messier 15 as imaged by the Hubble Space Telescope. Image credit: Wiki Commons.

M 15 is easy to find about 4 degrees northwest of Epsilon Pegasi. At magnitude 6.3 it’s just within the visual range, provided you have keen eyesight and observe under a dark, country sky. The finder view is very distinctive, as the globular sits a mere half a Moon diameter due west of the magnitude 6.1 star. It pays to study the field at low power. Both objects are of the 6th magnitude but that of the globular is integrated, while that of the star is a point source. This is a good place to learn the difference between the two concepts.

The view of M15 is impressive with anything from binoculars to the largest telescope. telescopes of 4 inch aperture and lesswill not resolve the core of M15. My 4 inch Clark refractor at 40x shows M15 as a slightly oval disk, more luminous in the center, with edges just beginning to break up into individual stars. Increasing the magnification enhances the view, and at 200x stars at the center of the cluster star to be resolved.

pp 223.

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Author’s note: M15 is a beautiful object at 150x in my 8 inch f/6 reflector. If you have a telescope of 12 inches or larger, M15 presents an extra challenge for you. Located in the northeast corner of the cluster is the 14th magnitude planetary nebula, Pease 1 (mentioned by Scotty on page 224). This was the first planetary to be found within a globular cluster. It was discovered in 1928 by Dr. Francis Gladheim using the 100 inch Hooker reflector atop Mount Wilson.

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Moving to the northern edge of Aquarius, the Water Bearer. You can track this magnitude 6.6 globular a little over 4 degrees north of Beta Aquarii. My 130mm f/5 reflector at 100x shows it be noticeably elliptical and more condensed than M 15 but still a fine sight nonetheless. Scotty writes some interesting notes on M2:

The famous variable starobserver and comet discoverer Leslie Peltier finds M2 a more difficult object for the unaided eye than M33, the large spiral galaxy in Triangulum. In the clear dark skies over the Yucatan peninsula in Central America I could view M33 directly, but M2 required averated vision before it could be glimpsed directly. But I have seen M2 often with the naked eye in Kansas, Missouri, Arizona, and even from the bayous of Louisiana. Binoculars give enough detail to keep the amateur interested, while the view I once had with the Wesleyan University’s 20 inch Clark refractor was spellbinding.

pp 225

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Author’s note: I would agree with Scotty that you’ll need a good 12 inch (see page 226) or larger telescope and high magnification to fully resolve this globular cluster

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As a child  I would stand outside on autumn evenings and fantasize about constellations. I would watch as the horse archer Sagittarius shot a golden arrow at Scutum( Sobieski’s Shield). The arrow would strike the top of the shiled, tearing a great hole in it, and the fragments would fall back together as the arrow shaped open cluster M1.  The arrow would then soar upward into the star clouds, where it would hang poised for another  target in the Milky Way or perhaps another galaxy or even some imaginary other universe.

pp 226

With beguiling prose like this, Scotty would set his readers reeling for crystal clear skies. This is how he introduces his next object, the globular cluster, M71 in the peitite constellation of Sagitta, the Celestial Arrow, easily found immediately north of Aquila. Scotty says he first spied this 8th magnitude cluster with his 40x spyglass of 1 inch aperture. You can pick M71 fairly easily as it lies about midway between the third magnitude luminaries, Delta and Gamma Sagittae.

My 130mm f/5 reflector at 123x shows up a suprising number of stars (about two dozen) in this globular in a pretty stellar hinterland. Indeed, one can be fooled into thinking M71 is a dense open cluster rather than a bona fide globular. Scotty provides us with these notes;

My old 10 inch f/8.6 reflector, which, with its 0.75 inch thick plate glass mirror, was essentially a forerunner of today’s Dobsonians, gave a magnificent view of M71 at 100x. Stars were visible across the entire disk, and the object looked decidely like  an open clusterThe 20 inch Clark at Wesleyan University’s Van Vleck Observatory in Connecticut shows something  more globular.

pp 228

On pages 230 though 232 Houston discusses the celebrated Helix Nebula (NGC 7293) in Aquarius. In his discourse, Scotty includes the descriptions provided by dozens of observers using all manner of telescopic aids and is well worth a read.

On page 234, Twinky discloses a wonderful snippet of American astronomical history:

After the U.S. Civil War, however, Americans went on an observatory building binge. Funding for many installions came from state legislatures, since the astronomers provided time signals to their local areas. Almost every observatory from that era had a transit instrument for determining time. In return for their service, the lawmakers funded a large telescope to keep the astronomers happy. When I was at the University of Wisconsin in the 1930s, Wasburn Observatory still had the big brass fittings on the control board that routed time signals to commercial customers…. Most American observatories did not have special programs to search for deep sky objects.

pp 234

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Author’s note: As explained in my book, Choosing and Using a Refracting Telescope, the largest equatorially mounted telescope in the United States in 1830 was a 5 inch Dollond refractor. Henry Fitz  is reputed to have made about half of all the telescopes sold in America between 1840 and 1855. Soon other makers of renown were establishing themselves, including  Alvan Clark & Sons and John Brashear, who improved and continued this telescope making legacy for the next 80 years or so. The great classical refractors, erected in their ‘cathedrals’ dedicated to the heavens, were symbolic of the new scientific confidence that the United States would enjoy well into the 20th century.

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The final pages of this month’s chapter (236 through 238) discuss a number of deep sky objects south of Fomalhaut, many of which were discovered by Sir John Herschel from his observing station at the Cape of Good Hope, South Arica.

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Chapter 11: November

We’re now approaching the end of the observer’s year but that certainly doesn’t mean there will be any let up in the convoy of celestial treasures to be enjoyed. In many ways, Scotty leaves the best until last, exploring as he does the bountiful constellations of Cassiopeia, and Andromeda riding high in November skies, as well as venturing to more southerly destinations in Pisces and Sculptor.

Scotty gets us off to a flying start by exploring a number of beautiful open clusters in Cassiopeia, the Celestial Queen, including NGC 457, NGC 436 and the visually striking NGC 7789.

The beautiful and exceedingly rich open cluster, NGC 7789, in Cassiopeia. Image credit: Hew Holooks.

 

 

 

 

 

 

 

 

 

 

 

No treatise on deep sky observing could fail to ignore NGC 7789, found about halfway between Rho and Sigma Cassiopeiae. Discovered by Caroline Herschel back in 1783, my 130mm f/5 reflector frames the cluster beautifully at 85x, revealing at least three score stars spalshed across an area roughly one quarter the size of the full Moon, and the 8 inch pulls in more than 100 at moderate powers! Scotty doesn’t hold back describing the splendour of this rich galactic cluster 6,000 light years away from the solar system;

NGC 7789 is one of those rare objects that is impressive in any size instrument. With a 4 inch rich field telescope the cluster appears  as a soft glow nearly 0.5 degrees across and speckled with tiny, often elusive, individual stars. the 12 inch f/17 Porter turret telescope at Stellafane picks up more than 100 stars. Through a 16 inch aperture the view is spectacular, and the whole field is scattered with diamond dust. And a 22 inch Dobsonian reflector in the clear skies of california gave a most impressive view with countless sparkling points filling an entire 60x field. I particularly like the drawing made by [Admiral W.H] Smyth with a 6 inch refractor.

pp 243

Another object of note in these pages is M 52. To find this 7th magnitude cluster, consider an imaginary line running from Shedir to Caph. Now extend this line about the same distance again until your finder picks up a roughly kidney shaped foggy patch of light a little less than half the size of the full Moon in diameter.

M52 ; a fine open cluster for small telescopes in Cassiopeia. Image credit: Wiki Commons.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

November is a great month for observing the Andromeda Galaxy (M31), easily found with the naked eye from a fairly dark site a few degrees about Mirach (Beta Andromedae).  Large binoculars can often provide the best views of this enormous spiral galaxy on our doorstep but I am also very pleased with the view served up by my 80mm f/5 refractor coupled to a 32mm Plossl delivering 13x. It shows a very bright nucleus which gradually fades on either side. Just how far one can trace the spiral arms of M31 depends on a number of factors, not least of which is telescopic aperture, visual acuity, sky darkness and transparency. Most backyard ‘scopes can trace them to maybe 3 degrees from end to end, but Scotty informs his readers on page 246 that George P. Bond, employing the 15 inch refractor at Harvard College Observatory was able to follow the spiral arms out to 4 degrees as far back as 1847. Yet, in 1953, Robert Jonckheere, using ordinary 50mm binoculars measured their visble length to be 5.17 angular degrees!  Scotty recommends moving the nucleus out of the field to have the best chance of tracing these spiral arms. Indeed, he claims that after using 15 x 75 binoculars, he was able to measure a length of 5 degrees from end to end!

The great Spiral Galaxy in Andromeda seen here with its bright satellite galaxies, M32 left and M110 ( below to the right of centre). Image credit: Torben Hansen.

 

 

 

 

 

 

 

 

 

 

 

The two bright satellite galaxies attend M31, both of which are easily discerned in my 80mm refractor at the lowest power. M32 lies closer to the core of M31, whilst M110 is located further away ‘below’ the disc of M31. Scotty also reminds his readers that two other companion galaxies can be ferreted out some 7 degrees north of M31; NGC 147 and NGC 185. NGC 147 (actually located over the border in Cassiopeia)., which shines with an integrated magnitude of 9.5 can be found just under 2 angular degrees west of Omicron Cassiopeiae. The other galaxy, NGC 185, is slightly brighter, owing to its smaller, more compact size. It lies just one degree east of NGC 147. Both are well framed in my 8 inch reflector at 30x.

Scotty then moves down to Pisces, to visit the grand face on spiral galaxy, M 74. This magnitude 9.2 gem is easily located in my 80mm refractor by centering the 3rd magnitude Eta Piscium in a low power field. The galaxy is then seen as a ‘fuzzy star’ about 1.3 degrees off to the east and slightly to the north of Eta. You need a larger telescope to make out the spiral nature of this galaxy though. My 8 inch at 150x shows a number of faint stars splashed around its periphery and with good transparency, you’ll be able to make out something of its spiral nature but not a great deal. In general, it’s best to use the largest telescope available to engage in this kind of work.

After discussing some less well known faint fuzzies in Pisces, Scotty finally moves into Sculptor, featuring some of the observations of Ron Morales, Barbara Wilson and Steve Coe.

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Chapter 12: December

The stuff dreams are made of; the Pleiades Cluster in Taurus, with its associated nebulosity. Image credit; Wiki Commons.

December brings winter, and with it many cold but often clear nights. On such evenings, when the stars sparkle like diamonds, there is no sight as spectacular as M45, the Pleiades. Currently, this open star cluster rides high in the eastern sky at the end of astronomical twilight. It is delightful in any instrument, from the naked eye to the largest amateur instrument, although I find large binoculars give the most impressive view. Almost every culture, past and present, mentions in its folklore the dazzling stars in this nearby culture. They have enhanced the imaginations of gifted poet and commoner alike as far as we can remember. They are the starry seven of Keats, the fireflies tangled in a silver braid of Tennyson, the fire god’s flame of the old Hindus, and the ceremonial razor of old Japan. No other celestial configuration appears so often on the pages of the poet.

pp 261.

There can be few sights that move the human spirit more deeply than the sight of the Seven Sisters rising serenely in a dark country sky. The cruelty of winter frost temporarily abates, as the mind soars. Why is the night sky so beautiful? Why were the stars made? Different people have different answers to these questions but to me they plainly attest to a Creator who delights in fashioning beautiful things, and was gracious enough to place them in the firmament so that we might know something of His awesome power. Rich or poor, young or old, the Pleiades is for everyone.

Not surprisngly, Scotty has a lot to say about this magnificent star cluster. How many stars can you see within its confines? Most have no trouble making out six members. With a little practice, a seventh can be made out, but the keenest eyes report more, many more.

Depending on light pollution and sky conditions , most persons can see between four and six naked eye Pleiads.Traditionally, the average eye can see six stars here, the exceptional eye seven, and 10 bear names or Flamsteed numbers. However, during the 1800s the noted British amateurs Richard Carrington and William Denning both counted 14 stars. The late dean of visual observers, Leslie Peltier, told me he could always see 12 to 14 stars on any good moonless night.

pp 263.

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Author’s note: Having average eyesight, I can usually only count 6 members, but have certainly glimpsed a seventh but only in the darkest skies that Scotland can offer. If you have a good, blackened telescope tube (without its lenses) lying about, try peering through it to minimise the amount of peripheral light entering your eye. Can you see any more? Indeed, in perusing the work of the Victorian populariser of astronomy, Sir Robert Ball, I recall him stating that one could see stars during broad daylight if one were to observe from the bottom of a deep well. Alas, I can’t confirm this! 19th century skies were considerably darker than those we typically enjoy today, helping to explain why these observers of old saw so many more Pleiads than we generally can.

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On page 263 through 265, Houston discusses the nebulosity enveloping M45, itself a good sign that the cluster is relatively young ( of the order of a few tens of millions of years most likely). The area of sky around  the star Merope is usually the place where most amateurs report such nebulosity. Technically this is a reflection nebula, where the star light is insufficiently energetic to ionize the gas but enough to allow it to get scattered off innumerable dust grains within the cluster. It was first reported by the German amateur astronomer, Wilhelm Tempel, back in 1859 using a 4 inch Steinheil refractor whilst working in Italy. Scotty points out that seeing this nebulosity depends strongly on the conditions of the sky through which we observe;

From Tucson my 4 inch showed it readily. In Connecticut, a 10 inch reflector failed but in Vermont a 5 inch Moonwatch Apogee telescope succeeded. At the August convention of the Astronomical League in Tennessee, I was surprised to find several observers who had seen the Merope Nebula more than once. It was readily visible in a 6 inch reflector made by Fred Lossing of Ottawa. Once its position southwest of the star Merope was pointed out, others saw the dim glow too. In the 16 inch, the nebula seemed much more obvious, and averted vision was not required.

pp 263.

The Crab Nebula (M1) in Taurus. Image credit: Wiki Commons.

Of course, the Pleiades is grand star cluster within the larger constellation of Taurus, the Bull, and on page 265 Scotty discusses a few other gems that are visible within the constellation using the naked eye, binoculars or a modest telescope. The Hyades is a sight to behold with the naked eye or through low power binoculars or even opera glasses. Then there is the Crab Nebula (M1), which is best found by centering the star Zeta Tauri in the low power field of view of your telescope and then panning 1 degree to the northeast. The Crab is rather disappointing telescopically as it certainly does not resemble the images seen in long exposure photographs, and increasing aperture doesn’t greatly transform the view. Scotty agrees:

The Crab can be seen in 2 inch finders. Small telescopes reveal only a shapeless 8th magnitude blur variously sketched as oval, rectangular, or more often something in between.

pp 268

After discussing a few deep sky objects in Cetus, Scotty throws caution to the wind and encourages sky gazers to return to the easy objects that delighted us in our youth:

As many of us know, the telescope is a wondrous invention, and the heavens contain all manner of marvels that can still astound the imaginative mind, no matter what the smog density may be. Some of the better sights await us in the December evening sky. The Northern Cross is erect in the Northwest; Albireo has already set. Pegasus is now a great diamond shape sloping slowly to the west, as Orion mounts closer to the meridian. This is no time for routine or difficult objects; it is better that we sweep again the old favorites of our youth; the sights that enthralled us with our first homemade reflector.

pp 276

By now, old Twinky was already thinking about the great sights that he would revisit in the new year; the Great Nebula in Orion, Barnard’s Loop, the magnificent Double Cluster; and so it begins again!

Dr. Neil English’s new book, Tales from the Golden Age of Astronomy will be published in the Spring of 2018.

 

De Fideli.

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