The quest for the deep...hunting Stephan's Quintet and the Deer Lick Galaxy's fleas in Pegasus

"Annotated deep field of the Deer Lick and Stephan's Quintet Galaxy Groups"

Prelude

One of the things I set out to do as a visual astronomer was to strive to go deeper whenever possible. I made a pledge to do this when I got my 10" GS dobsonian back in 2007, and go deep I did, seeking out fainter fare, detail in fainter objects, as well as pushing the magnifications as high as I could to eek out as much detail in the brighter planetary nebulae and globular clusters. One thing that always eluded me though was galaxy clusters. The Abell's and the Hickson's were still out of reach, and my best guess is that the smallest sized scope for such an endeavour would be at least a 12.5" scope. I am partially right though, some of these are doable in a 10". That said there is no detail visible, and under most circumstances all you see is one extremely faint blob with no resolution of its individual members.

Abell and Hickson Galaxy Clusters

So what are the Abell and Hickson's? The Abell catalog of galaxy clusters is an all sky catalog containing 4,073 rich galaxy clusters. The original list, published in 1958 by George O. Abell only contained 2,712 galaxy clusters, the "Northern Survey". This catalog was revised and 1,361 clusters from the "Southern Survey" was added by co-authors Harold G. Corwin and Ronal P. Olowin in 1989.

The Hickson Compact Group, also known as HCG is another collection of faint and compact galaxy groups, numbered at 100 and published by Paul Hickson in 1982. The most famous of this is of course one of my quarry's, HCG92, Stephan's Quintet. Both the Abell and Hickson catalog of objects are regarded as observational targets for advanced visual astronomers with big telescopes from the darkest skies!

The most famous and probably most observed of these clusters is Stephan's Quintet and NGC 7331, the Deer Lick galaxy group (and its smaller companions, the fleas). These two objects are only just above the threshold of a 10" scope. While NGC7331 is easy, the fleas are not visible. As for Stephan's Quintet, well lest just say all I though I saw was a faint haze that was barely there with averted vision. There was no galaxy cluster per se. That makes what I just accomplished all the more impressive, and this with a scope a fraction of the size of my 10". Least to say I am a convert to CCD imaging. Presented below is an image I took of section of the cosmos that showcases the above-mentioned galaxy clusters, in the northern reaches of Pegasus the winged horse. Not only does the Quintet make an appearance, I can actually make out its individual members (see asteriks denoting the members).

Also in the same frame, we have NGC 7331, the Deer Lick Galaxy and its companion galaxies, the fleas. This image was a composite of 10x42sec exposures through a 70mm Celestron Travelscope optical tube assembly riding on a NexStar GOTO alt-az mount, no tracking! The CCD camera of choice is my new-old Meade DSI II OSC. Since the focal length of the OTA is only 400mm, my guess is that my 102mm OTA at 1000mm would frame it better...and frame it way better it did. Below is the result of last weekends dark sky imaging trip to Saratoga Gap. All the major members are now fully resolved, and I have annotated my images. See figure legends for details of the subs and exposure times. I can only imagine how much more can be captured if I had a EQ GOTO mount for longer sub exposures. But I am happy with what I captured with my cheap and simple imaging gear!!!!

Wide Field Imaging of both clusters in the 70TS at 400mm focal length on NexStar GOTO

"Stephan's Quintet and Deer Lick Galaxy clusters: 70TS: 400mm focal length: 10x42sec"

A Closer Look: Imaging with the 102GT at full focal length 1000mm on NexStar GOTO

"Deer Lick Galaxy: NGC7331, NGC 7735, NGC7336, NGC7337, NGC7340: 102GT: 1000mm focal length 20x21sec"

"Stephan's Quintet: NGC7317, NGC7318, NGC7319, NGC7320, NGC7320C: 102GT: 1000mm focal length 20x21sec"

The results I obtained for this "deeper sky" imaging session was indeed very encouraging. I might try my hand with imaging some of the brighter Abell and Hickson clusters the next time the new moon comes around. Stay tuned for more......

Astro nostalgia: My vintage scope collection

Isn't it funny how a lot of our life choices are dictated by a certain time point in our development. For me, I seem to be stuck in an eternal 80's loop. All my hobbies, my music choices, etc are 80's centric. Well I was born in the early 70's, but did most of my growing up in the late 70's and early to mid 80's when I started to take note of the world around me. Amateur astronomy was a big part of those years. Star Wars burst onto the big screen in 1977 and that had a HUGE influence on me! The telescope was like my X Wing fighter as I took off to the stars every clear night at my parents yard. I remember those years as they were just yesterday, getting my first scope, a dodgy plastic objective, plastic body tabletop toy 40mm scope with eyepieces the size of a peashooter. I would later come into the possession of my dad's beat up 20x50mm porro prism Japanese made binoculars, and a Celestron Cometron CO40 with real two element fully coated achromatic objectives. I used the buggery out of those two to observe celestial bodies and deep sky objects, moving around my parents front lawn, yard, and even climbed onto the roof to spy Halley's Comet in the predawn sky. Contrary to what most beginners experienced (maybe it was just my tenacious scientific nature), the small aperture did not deter me from digging deep and trying to see as much as I could. I remember going to the libraries to look for star charts, and writing to the local astronomical society, based in my country's capital of Kuala Lumpur. I exchanged several letters with Professor SM Chong as he gave me tips and sent me photocopies of star charts, etc. I will never forget his patience, mentoring this young budding scientist. Thank you prof if you ever read this!!!! I also exchanged several letters with the BAA in UK. I did not have the money back then to join any society but they were very patient and sent me photocopies, just like prof.

Upon reflection, I now realise that the bulk of my observing menagerie consist of used scopes which I purchased over the years via Astromart getting back into the hobby in 2001. I put together a list, as well as photographs of me and my scopes! The trend continues on till today. Most of my scopes are Celestron's (my first scope was a Celestron), and all of them belong to the 80's. Enjoy!

Turn back the clock (by Johnny Hates Jazz):

Celestron Cometron CO40 (40mm f/20) Alt Az Japan (mid 80's vintage)

The scope that started it all for me. I know its extremely small by today's standard's, and most would probably label this as a CTT. Celestron had these for sale to capture the Halley's Comet craze flyby. The optics are fully coated but this scope showed me so much, from Saturn's rings and Jupiter's belts and moons to deep sky delights such as M8 and M22. Scope has the nostalgic Cometron orange bakelit tube, 5x24 stoppered down finderscope with metal base, a plastic body prism diagonal and a 25mm Celestron Kellner and a 8mm Celestron HM in 0.965" size.

Celestron Cometron CO60 (60mm f/15) achromatic refractor on Vixen Polaris Mount EQ (mid 80's vintage)

"Celestron Cometron CO60EQ"

This is the scope that ended my search for the ultimate vintage 60mm scope, having gone through no less than five 60mm scopes (Kasai 60mm ST, Yosco 60mm, its alt az brother CO60, Orion OmniVista 60mm ST, Meade 226 60mm and even a Burgess 65mm BackPacker ED). Its long focal length does extremely well to suppress chromatic aberration yielding very neutral color images, similar to the above scope. The scope came with the same crappy stoppered down 5x24mm eyepiece with metal base, a much better metal bodied prism diagonal and just one eyepiece, a 10mm Celestron Kellner in the 0.965" size. The best part of this ensemble is the mount that comes with the scope, the much vaunted Vixen Polaris mount. This mount it totally overkill for the scope, and back in the day came packaged with their 80mm and C6 scopes!!!!!!

Edmund Astroscan (105mm f/4.2) newtonian reflector (unknown vintage)

"The dimunitive Edmund Astroscan"

Always wanted one of these bombproof scopes. Glad I got one since Edmund is currently no longer manufacturing them! I know the parabolic optics are sealed and non collimatible and it is only good for low powered wide field scanning but boy is this scope a joy to use, so long as you have something to set it on. All you need is a dark sky, some sort of pointing device (since its hard to sight down the tube due to its bulbous back). My favourite eyepiece to use with this scope is my 13T6 Nagler! Since I got this used, it did not come with the original eyepieces, the Edmund RKE eyepieces. Also there was no non powered finder on mine so I got a red dot finder for the scope. I plan to hand this scope down to my lil one in the future. In fact she has already started using it! Came with the shoulder strap and metal base.

Celestron Vixen C6 (6" f/5) newtonian reflector mounted on Vixen Porta Mount (mid 80's vintage)

"Celestron C8 SCT"

My first real scope was a beat up C6 with super excellent optics that constantly surpassed the views in other Chinese and Taiwanese made 6" f/5 scopes. I think it was the "special" coatings on the optics cause my scope constantly went deeper in comparison to the mentioned (compared side by side with other 6" f/5 scopes). Gorgeously sharp views of Jupiter's cloud belts, the big red spot (salmon spot ;), Saturn's Cassini's Division and C ring and super sharp views of DSO's. Fave eyepiece to use in this scope was the Orion Expanse 20mm. Surprisingly very little detectable coma for such a fast scope! There are some caveat's though. The sliding focuser takes a little getting used to and personally I prefer rack and pinion or Crayford focusers. Also the secondary mirror is a little larger than required for visual use, although the stated literature says that this is required for full field immunimation for astrophotography. Since I got the OTA only, there was no finder, mount or eyepiece on mine. I used it on am EQ3-2 mount for years, and recently on a Vixen Porta Mount. Now that I have a Polaris mount (see above), I hope to get a new set of tube rings so I can mount this on the mount it was old with!!!

Celestron C8 (8" f/10) SCT mounted on Orion VersaGo III (mid 80's vintage)

"Celestron-Vixen C6 Newtonian"

My current largest scope and what a performer!  Replaced my bulky but trusty 10" dobsonian with this OTA. I am beginning to understand the allure of a large SCT! You do see much more sitting down and observing. I was always bending and contorting when using my dob, even when seated as I did not have one of those fancy adjustable astro chairs! Views are just as bright and detailed as in my 10" dob, and it is so much easier to move around (big factor for me as I like moving around the yard when observing). Also great when I was living in a two storey apartment, and we did not have a lockup garage. With this scope I can carry the whole observing rig in one sitting. With the dob it was two trips, the tube and then the mount. Although not super heavy, it was super awkward to move due to the length and girth of the optical tube. All I got was the OTA, Telrad finder, and a 1.25" visual back so I had to supplement the scope with an optical finder (I prefer the 50mm finders for larger scopes), a diagonal (purchased a 2" Orion SCT diagonal used) and a low powered wide field eyepiece (my lowest powered 1.25" is my Meade 24.5mm ep and that gave  81x). Got the Orion DeepView 40mm three element ep as this gives the lowest and brightest views. No need for fancy ep's in a scope with a long focal length!

Epilogue

There are still some 80's scopes which I have set my sights upon that I have still to acquire. The two include Edmund Scientific's 76mm red tubed newtonian on an alt az equatorial (yup it is set at an angle!) and Celestron's Schmidt Newtonian Comet Catcher (Orange Tubed Version). Whether I get these, only time will tell. I only purchase something if I can get it at a good price!!!!!