Let the good times roll. Summer spectacles, at their best!

Time sure does fly. This is my 6^th summer in the northern hemisphere. As in Australia, this also happens to be the best time of the year to explore the summer wonders straddling the constellations of Sagittarius and Scorpius, the center of our glorious milky way, as well as northern sky wonders in the summer triangle. This time of the year is also the only time the center of our home galaxy is on display, granted that it is not as high in the sky as down south. Still so many bright objects to image and observe, and so little time ;)

Best place to start is still at the heart of our galaxy. It does not matter whether you are using your naked eye, small binoculars, or a large truss tube dobsonian reflector. This is the best spot in the whole galaxy to begin your exploration of our universe. Here we find the wondrous pairing of M8, The Lagoon Nebula and M20, The Trifid Nebula. Both are amazing sights in their own right and can just be observed in a single field if you have a wide enough FOV eyepiece.

From light polluted sites, the nebulosity in M8  get overpowered by the star cluster embedded in its embryonic cocoon. A UHC type narrowband filter will bring some its majesty out from the background glow, but you get the best views of this object from dark sky sites. M8 covers an amazing amount of sky from darker skies, and the dark lane that bisects the nebula (hence the lagoon nebula moniker) stands out in stark relieve. In fact I find there is a ripple effect from the major dark lane, and you can make these “ripples” out under steady skies. Also the hourglass nebula, at the heart of the nebula is best seen at slightly higher magnifications.

While not nearly as “stunning” as the Lagoon, The Trifid Nebula is also an easy’ish object to observe even in binoculars. With my 8x42 lightweight binoculars, the fuzz surrounding the stars is clearly evident. This fuzz is resolved into a tri lobed structure bisected by dark lanes even in my 76mm Newtonian at lower magnifications under dark skies. In my 6” f/5 newtonian, I can make out a small island in the middle surrounding the double star at the heart of the nebula. What makes this object interesting is that it actually composed of three different classes of nebulae. The many “body” of the nebula is emission in nature, bisected by dark fingers of dark nebulae. There is also a reflection component to this object that is only visible if you observe from dark skies without the use of a narrowband filter. From light polluted sites, try using an 8” scope. At 100x magnification, with a UHC type filter in place, I can make out the central island, as well as the dark lanes with a little bit of averted vision.

Also in this area of the sky are two more “outstanding” summer nebulas, M17, The Swan or Omega Nebula and M16, The Eagle or Little Ghost Nebula. While further apart, if your scope can go under 20x magnification, you may just be able to fit these two in a single field of view. Both benefit best from dark skies. M17 shows its outer “bubble” of nebulosity from dark skies, surrounding its inner graceful swan shape. From light polluted skies, with an 8” scope, with a UHC type filter, this object comes alive. But to really see detail, there is no substitute for dark skies. Under such skies, dark lanes crisscross the body of the swan, and I get the feathery texture effect down the back of the swan. Also the dark nebula in the neck region is fairly obvious.

Like The Swan, M16 looks best under dark skies as well, but this one suffers more under light polluted skies. Under such skies, I use the same combo in my 8”, but can only make out the “shape” of the eagle with averted vision. From darker skies, I tend to see what Stephen O’Meara sees, a little kid under some white sheets with their hands sticking out to the sides. This effect is more obvious when I screw in my UHC filter. From light polluted skies, for most part all I can make out is some misshapen fuzz surrounding the star cluster without a UHC type filter.

Summer is also an excellent time to view globular clusters, and there are heaps of them abound since the center of our galaxy is in full display. The best part about globular clusters is that they all have individual characters, provided you have enough aperture to break them up. The minimum aperture required for a good view of globulars in my opinion is a scope 6” and larger. At this aperture you start to resolve some of the smaller globs, as well as fully resolve some of the bigger and brighter ones. The best globulars, in my opinion are M4 in Scorpius, M22 and M55 in Sagittarius , M13 in Hercules and M5 in Serpens. I chose these five as they are easy to resolve in scopes as small as 76mm.

M4 is known as the cat’s eye globular for a reason. There is a small bar of stars crossing the width of the globular that is readily resolvable in small scopes. This globular has the most character in small scopes (well there are other’s that are nice, but they are mostly southern globulars and are not visible from northern latitudes) since it has that unique feature. Also the overall branch magnitude of its constituent stars are higher, making it more resolvable.

Seeing how I moved from the southern hemisphere, I refer to M22 and M55 as poor man’s Omega Centauri. Now I am sure you have all heard of Omega Centauri and how brilliant and resolvable this huge southern globular is. M22 and M55 are close in visual appearance. Both are fairly loose globulars, appearing more like open clusters at very high magnification in larger scopes. M22 also appears oval in shape, much like its larger cousin due to its fast rotational speed. Both globulars are a joy from dark skies, even in scopes as small as 76mm. I see good resolution in both. But for a good view I would suggest using at least a 130mm scope.

M13 in Hercules is a weird one. Hailed the best of the north, and yet not the best in my humble opinion. I reserve that throne for M5 in Serpens (that is discounting M22 since atmospheric extinction removes that splendor for most of the folks living further north). M13 has a tight core, similar to 47 Tucana in the south (although I feel M5 is more the poor man’s 47 Tuc not M13!). There is very little resolution (well there is at the periphery) in small scopes (76mm-114mm). The globular only starts to get interesting, and at magnifications about 100x I might add in scopes 6” and larger. In those scopes, you get resolution down to the blurry core (although for the best and most consistent views, you need at least an 8” scope). In the 8” scope, I can make out the propeller effect in the globular. In this regard, M5 is better, showing more resolution in the smaller scopes than M13.

And there you have it, the summers best all wrapped up in a single blog entry. I hope to do more visual observing in the coming months, at least until Orion and friends show up early winter to revisit some of my imaging targets. Till then enjoy.

Saratoga Gap Report 30th April 2016

My first dark sky trip since the end of last year. Yes it has been that long, 4 months long (well 5 if you factor in my year-end holidays back home at the equator). Weather has not been the best for the last few months since the start of the year. We have been getting heavy cloud cover and rains, yes rains, for the past few months. Granted that this is not the best case scenario for amateur astronomers like me, we really needed the rains as it has been bone dry here in CA for a while now.

 "M97, The Owl Nebula in Ursa Major"

Prior to the bad weather, my agenda for the first quarter of the year was to image Orion and its surrounds one more time (I am still not satisfied with my Flame and Horsehead Nebula shots). My plan was to also image The Eskimo Nebula in Gemini at full focal length in the 102GT, without the focal reducer. I find I get very good images of small objects when using such a setup. I managed the last one easily from my backyard one clear night with a nebula filter in tow. Since the window for Orion had passed, my next objective was to go for Ursa Major and re-image some of its principal objects, namely M81 (Bode’s Galaxy), M82 (Starburst Galaxy), M101 (Pinwheel Galaxy), M51, and M91 (The Owl Nebula). All of these objects are bright and rather easy, with the exception of M101 due to its face on nature, spreading its light across a rather large portion of the starry sky. I have imaged this galaxy in the past, but with my 102GT equipped with a 0.5x focal reducer. This time I was going to attempt to shoot it with my RFT, the 400mm focal length 70mm Celestron Travelscope.

"M82 in Ursa Major"

Setup was as usual. I started imaging with the Travelscope 70 at full focal length (can’t use the focal reducer anyway even if I wanted to with this setup) on the NexStar GT mount coupled with the Meade DSI II OSC. With this, I can usually go up to 42 seconds exposures without trailing. I intended to push the envelope tonight, and with everything working in synchrony (which happens once in the blue moon!), I managed to even get the exposures up to 1 minute without trailing. I targeted 10 to 15 exposures at 42sec to 1 minute each for the objects. The main bug bear with alt-az GOTO mounts without a wedge is the field rotation. And this problem is exacerbated the closer you image to the pole star, something which I was doing tonight.  As such, I had my work cut out for me post processing. Also the light pollution from my dark sky site is worse towards the north. This also showed up in my images as muddy background, despite the multi-image stacking. Still, overall I was pleased with my results. The Owl clearly showed its true nature (and colors), as well as its two eyes, something that was missing from my “grainy” first attempt back at Solstice Canyon, Malibu when I first started imaging with my rig.

"M51, The Whirlpool Galaxy in Ursa Major"

M101 looked heaps better in the wide field shot, even with the muddy background, with its spiral arms and condensations indicating star forming regions standing out against the background. M51 is a great object to image and never disappoints, its spiral arms popping out from the background and reaching out towards its neighboring NGC galaxy. M81, as always, was a pretty meh object to image as it’s tightly wound spiral arms are notoriously difficult to image unless you get a very deep image of this galaxy. After completing my imaging run, I swapped my imaging scope out for my visual scope, the 102GT and perused some of the summer wonders rising from the east. Hit M57, as well as some of the now setting galaxies in Virgo and Coma. Observed till the batteries died at close to 2am!

"M101, The Pinwheel Galaxy in Ursa Major"

 

With the rainy weather now behind us, and the balmy summer skies beckoning, I might actually take a break from imaging to enjoy the wonders of our milky way through my larger scopes. But who knows, the astrophotography bug might strike yet again and I may target some of the smaller summer planetaries. Till the next time.

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!!!!!

Let's talk about planetary nebulae!

When I first got back into visual stargazing in 2001, one of the objects that was top on my list to re-discover and re-observe with my then largest telescope, a 76mm f/9.3 newtonian reflector, was a planetary nebula familiar to most amateur astronomers, M57, The Ring Nebula. I have always been fascinated with planetaries. However back in the day, when all I had was my trusty 40mm long focal length Celestron Cometron refractor, I was severely limited to only the brightest planetaries, M57 and M27. From my rather light polluted backyard in the 80's (back then probably red zone skies??!!), I spied a fuzzy star where M57 was to be. Yup no doughnut visage visible. The 3" reflector opened up a whole new world for me. The doughnut was not only there, it was rather bright too. And M27, the first planetary nebula to be discovered in 1764 by french comet ferret Charles Messier,  showed its dumbbell shape in my small scope. The nebula looked almost photographic in appearance after I obtained a Japanese made Orion SkyGlow filter in the 0.965" size. So began my love for planetary nebulae. With a narrowband filter, I began my quest to bag as many planetaries from my balcony observatory in Indooroopilly, and my dark sky site in Leyburn, Australia. Visually, mid sized planetaries were the easiest and showed the most detail. Large planetaries, such as the Helix Nebula in Aquarius, show up best in RFT's from dark sky sites with a narrowband filter. The most challenging of the planetaries were the small minute ones. These appear as tiny pinpricks no bigger than the stars themselves. The trick here is to "blink" them using a line filter such as a OIII filter. This is a trick used by advanced visual astronomers to confirm their quarry, since these filters dim the light from stars while allowing the light from the planetaries to pass through.

So what are planetary nebulae and how do they differ from supernova remnants? Well planetary nebulae are formed by stars that don't have sufficient mass to support a cataclysmic explosion to form a supernova. The usual suspects that puff out a shell of glowing gas after it has exhausted all its fuel are old red giant stars. Planetary nebulae are relatively short lived phenomenon, lasting only a few tens of thousands of years. As such they form all sorts of interesting shapes, some of which are visible to visual astronomers. Below are a selection of planetary nebulae that I have sketched and imaged. I have included a description of them and how to appear visually in a scope.

M57: The Ring Nebula, Magnitude: 8.8 Size: 230" x 230" (Lyra)

Discovered by Antoine Darquier in 1779, and a month later by the famous Charles Messier, this is one of the showcase planetary nebulae you see in the textbooks and observing manuals. Indeed it is one of the brighter and showier objects for beginners to deep sky observing. I remember seeing this object for the first time in my Cometron 40. It was nothing more than a blurry star. Probably due to its lack of light gathering power, no amount of magnifying allowed me to see the celestial doughnut visage. Years later, in 2001 to be precise, I saw this same object, as it should be seen, in my 76mm newtonian a ghostly ring of smoke! Now with several tens of years of visual observing under my belt, I can spot this object and make out its hollow tube visage even in a 60mm refractor. To see the inside of the hollow illuminated by ghostly luminiscensce you need at least an 8" scope. This object is even detectable as a out of focus star in my 8x40mm binoculars from dark sky sites. An easy object to image too!

M57 at 1000mm 102GT, DSI II

M57 at 400mm 70TS, DSI II

Sketch of M57 at 166x in the 6"

M27: The Dumbbell Nebula Magnitude: 7.5; Size: 8' x 5.6' (Vulpecula)

The first planetary nebula to ever be discovered, this is one of the few planetaries that looks like a planetary in small instruments. If all you have is a small pair of binoculars (most commonly available garden variety 7x50mm binoculars), this is the planetary I would recommend, since it is large and bright enough to cut through light pollution, and unlike the other smaller ones, this actually looks like its namesake! Through the telescope, it starts to strut its stuff, appearing almost photographic in appearance, with the help of narrowband filter of course. To me the nebula looks more like an apple-core from light polluted sites without a filter. Under dark skies, with a narrowband filter, this same nebula looks more like a football than a dumbbell or apple-core. What's cool about this nebula is you can actually see the background stars shining through the nebulosity!

M27 at 1000mm 102GT, DSI II

M27 at 400mm 70TS, DSI II

Sketch of M27 in at 47x the 6"

M76: The Little Dumbbell Magnitude: 10.1 ; Size: 2.7 x 1.8 arcmins (Perseus)

This is one of the supposedly harder objects to spot in the Messier list and one I had never seen due to its very northerly location. I found this object "easy" even from white zone skies in Los Angeles in my 6" (and later discovered that this object was also visible with a filter in my 102mm GOTO refractor), and this without the use of a narrowband filter. I guess the imposing visual magnitude discourages beginning observers from even trying. While it was "detectable" without the filter, I found the views to be vastly improved with the use of my DGM NPB narrowband filter. The views were even better when I obtained a OIII line filter! Appearing as a bar of light, this object need high magnification to do it justice. Imaging this was also ridiculously easy, and the CCD brought out the colors in the object!!!!

M76 at 1000mm 102GT, Meade DSI II

M76 at 400mm 70TS, Meade DSI II

Sketch of M76 at 37x in 6" and 50x in the 102GT

NGC 7293: The Helix Nebula Magnitude: 7.6; Size: 25' (Aquarius)

The largest and brightest of the planetary nebulae also happens to be one of the hardest ones to detect from light polluted locales. This is due to the fact that the object covers a very large portion of the sky and has a very low surface brightness. This is one object that is greatly enhanced by narrowband filters, and looks the best in very wide field instruments. This object is now detectable even from red zone skies with the help of OIII filters. Imaging wise, this is a brilliant object as it is so big. Color is also very evident, even with 30 second exposures!!!!!!

Helix at 400mm 70TS, DSI II

Helix Nebula at 56x in the 6" 

NGC2438 in M46 Magnitude: 1.8 ; Size: 1.1 arcmins (Puppis)

This is another very interesting planetary nebula that shows abundant detail in small scopes. Found in the southern constellation of Puppis, but high enough for northern hemisphere skywatchers to pick up, it is superimposed on the open cluster M46. Physically they are not associated, but they do make a very pretty pair. Greatly enhanced by the use of a narrowband filter, this one is large enough to not require too much magnification. Imaging this one required me to use a broadband imaging filter due to its altitude in the sky.

M46 and NGC2438 at 500mm 102GT, Meade DSI

Sketch of M46 and NGC2438 at 70x in the 6"

NGC7009: The Saturn Nebula Magnitude: 8; Size: 41" x 35" (Aquarius)

The famous Saturn Nebula does not reveal its secrets easily. I though I spied its famous ansae at 300x in my 10" dob, but that is a big "if" (big part of this is the seeing...and lil turbulence blurs this). Looking more like an bloated elongated star in smaller scopes, I have also yet to capture the "rings" using my 102GT at 1000mm.

Saturn Nebula at 1000mm 102GT, DSI II

NGC2392: The Eskimo Nebula Magnitude: 10.1; Size: 48" x 48" (Gemini)

This is another brilliant lil one that shows abundant detail in larger scopes. Visually I have detected the outer parka, and the subtle triangle in the central region making out the eskimo's face in my 10" at magnifications in excess of 300x. This same feature cannot be made out in the 6", but the outer parka is visible. Photographically I have been trying to get the exposure right to highlight its internal detail. All I have gotten so far is an outer and inner ring without any internal detail at 500mm focal length in the 102GT.

Eskimo Nebula at 500mm 102GT, DSI I

Clockwise: Eskimo Nebula at 400x in the 10", at 156x in the 6" and 70x in the 6"

NGC6818: Little Gem Nebula (Sagittarius)

This is another bright but small planetary that does not show much internal detail even in a 10" scope, but it does show a disc at higher magnifications. Color is evident visually in scopes 6" and larger. The best CCD image I have of this brilliant planetary was with the 102GT at 1000mm focal length, showing a nice lil green disc. 400mm just does not do justice to this object!

NGC6818 at 1000mm 102GT, DSI II

NGC7008: Fetus Nebula Magnitude: 12; Size: 1.4' x 1.1' (Cygnus)

Never knew what I was missing with this one. Amazingly bright and rather large, it is one of those you want to "scrutinise" at higher magnifications, if you have sufficient aperture. I have still yet to train my bigger scopes on this lil beauty. That said it looks pretty even in a 4" scope. CCD imaging brings out a whole level of detail. Even with my 70mm TS OTA there is abundant detail in this object. I need to re-image this at full focal length to see if I can get more detail out of this object.

NGC7008 at 400mm 70TS, DSI II

NGC3242: Ghost of Jupiter/ CBS eye Magnitude: 8.6 ; Size: 25" (Hydra)

One of the planetaries that actually looks like its namesake, this is a fairly large object which shows abundant detail in large apertures. Also known as the CBS eye, this curious feature is actually doable in apertures as small as 10". I have seen this at 300x magnification! This same feature is invisible in my C6! Have to try for it in my C8 next time I have a look at this. Imaging this with my Meade DSI II OSC was a lot harder than I though due to overexposure. I am still coming to grips with getting the exposure correct for the more compact and high surface brightness planetaries.

Clockwise: NGC3242 at 400x in the 10", 112x in the 6" and 56x in the 6"

NGC5189: Spiral Planetary Magnitude: 8.2; Size: 90 x 62 arcsec (Musca)

A strictly southern hemisphere object since this DSO is found in the small constellation of Musca, the fly. I remember my first views of this object through a SAS member's 16" truss dob (thanks Kevin Dixon!!) and though I was looking at a very detailed spiral galaxy!!! I later found out that this was a planetary nebula, and a very pretty and unique one at that. Also I discovered that it was bright and showed a lot of detail even in my C6 scope., even from light polluted Brisbane!!! Since it is a planetary nebula, it is greatly enhanced by narrowband filters. I have gotten great views of this in my 6" and 10" scopes even from red zone skies with the filter screwed on. A must see object if you are ever in the southern hemisphere!!!! Just wish I had a CCD cam and a tracking scope back in oz. This would have been an excellent subject to shoot!!!!!

Sketch of NGC5189 at 56x in the 6" 

NGC3132: Eight Burst Nebula/ Southern Ring Nebula Magnitude: 9.87; Size: 62" x 43" (Vela)

Technically this is still visible from the southern states in continental USA, although I have not tried to pick this up just yet. This was one of my favourite planetaries while living in Queensland, Australia, ranking right up there with M57 and M27! Big and bright, this one too needs magnification to do it justice, showing its multi-shell appearance at higher powers in my 6" and 10" scopes. In the 4.5", I can just make out its ringed appearance, although the multiple shell appearance eludes me. Like the rest of the mid sized planetaries, this also looks good from light polluted skies. All that is needed is higher magnification, or the use of a narrowband filter. Wish I could capture this on CCD! Maybe when I visit my old stomping grounds in the future!!!!

Clockwise: NGC3132 at 400x in the 10", 112x in the 6" and 56x in the 6"

NGC6302: Bug Nebula Magnitude: 7; Size: 3' (Scorpius)

This is one of my favourite southern planetaries, and also one which is visible from the northern hemisphere. It is brighter and exhibits more detail that most people realise, showing an elongated bar, with a pinch down the middle. Imaging this object with the Meade DSI II requires a SkyGlow Imaging filter as this object, while not a horizon skimmer, does not cumulate very high in the night sky. Visually, I find I can push the magnification pretty high on this one. Also does very well with a UHC or OIII type filter visually.

NGC6302 at 400mm 70TS, DSI II

Sketch of NGC6302 at 93x in the 6" 

What's new from the roost? Full focal length imaging of summer bounties with the 102GT and Meade DSI II OSC

Well I haven't posted in a while. Call it apathy. Call it the lack of motivation. I think it is a little bit of both. I have been actively observing and imaging, just maybe not as voracious as back when I first got my astrophotography setup. Now that I am more comfortable with getting DSO's in the narrow FOV of the Meade DSI II OSC in the wide field 70mm TS OTA, and the 102GT with 0.5x focal reducer, I was just wondering if I could take it a step further and image through the 102GT OTA without a focal reducer. That means I would be imaging at its full 1000mm focal length, as opposed to 500mm with the reducer, and 400mm with the wide field 70. Objects that would greatly benefit from this increased focal length (i.e. magnification!!!!) include globular clusters and planetary nebulae (hence my motivation since summer has only passed and a whole heap of summer DSO's are still ripe for the picking). With the 70TS, I generally found that I could push my subs to 42 seconds and still get sharp stars unguided. This number came down to 30 seconds on the 102GT with the Orion reducer. Playing around with the 102 at full focal length, 21 seconds seemed like the perfect sub exposure. I ran with this, seeing most of the objects I was going to image for the first time were brighter globular clusters, and some old faithful planetaries, that needed the extra oomph to get the details burned onto the pics. Below is a selection of some of the spoils of my imaging session at full focal length from my red zone San Jose skies. Enjoy.....

M30 Globular Cluster, Capricornus "The Wing Chun Wooden Dummy Cluster"

M55 Globular Cluster, Sagittarius 

M2 Globular Cluster, Aquarius

M13 Globular Cluster, Hercules "The Great Hercules Cluster"

M92 Globular Cluster, Hercules

NGC6818 Planetary Nebula, Sagittarius

NGC7009 Planetary Nebula, Aquarius "Saturn Nebula"

M4 Globular Cluster, Scorpius

M5 Globular Cluster, Serpens

M22 Globular Cluster, Sagittarius "Crackerjack Cluster"

M10 Globular Cluster, Ophiuchus

M12 Globular Cluster, Ophiuchus

M28 Globular Cluster, Sagittarius

M80 Globular Cluster, Scorpius

M11 Open Cluster, Scutum

It is interesting to see all of the globulars side by side as this is how they appear in the eyepiece at the same magnification. Till the next time...