Once the sun went down, I made another attempt to adjust the C11, since the evening started out partly cloudy, and it definitely looked better in the eyepiece, but the question remained - would it guide? I polar-aligned it again, using a tool called a belt wrench to help me turn the altitude adjustment knob. It was hard to figure out how to use right, but it did help a lot in being able to turn it once I got the hang of it. I used SharpCap's polar alignment tool again, which is kind of hard when you're not level, since after adjusting left and right, it wants you to adjust up and down again, and on it goes. Add my tripod to the list of things to fix...
It cleared up after 1 AM, so I decided to test out the C11 on the Sombrero Galaxy. I carefully focused with my Bahtinov mask on a nearby star (the same one that comes up for Precise Goto), and then I took some 180s frames. Guiding that evening was...not pretty. Mind you this is with a 600mm focal length scope mounted on top of my C11 using a Losmandy dovetail, the big wide ones, and a QHY5 mono camera.
The result is evident in the images.
Sorry, the bottom got cut off. Stupid Microsoft Paint
As I was going through all of the test images I took, it reminded me of back when I was first starting out, going through images where there'd be two or three bad ones in a row, then a good one, then a few more bad ones...periodic tracking error. I should not be seeing this when guiding. And it wasn't even only in one direction for the dec axis! I tried turning off guiding in declination, or only guiding one way, or turning on backlash compensation (although, as I had to explain to every person I talked to about this, this is not a backlash problem - when I took in an eyepiece, there is no delay whatsoever switching directions), but nothing seemed to help. The only thing I can think of at this point is that I'm still not quite adjusting the adjustment knob quite right for the worm gear in the dec axis. My RA axis was also slipping and binding a lot too though, for reasons unknown, as if I was not in balance. *sigh* I'm out of ideas. When I talked to a Celestron rep there about the problem, he was shocked to hear that I was having these issues with the CGE Pro, particularly since it had just been refurbished by Celestron last year and it's been Hypertuned. After the CGE and now the CGE Pro, I am starting to think that my next mount will not be manufactured by Celestron. I'm so done with this crap.
I tried the Sombrero Galaxy with 30-second images as well, and I had a larger number of usable frames, but none of the blue ones came out, unfortunately. On any of my targets. I've heard that the blue Astronomik filter I use, which they claim is parfocal, is just slightly not parfocal. Parfocal means that you don't have to change focus when switching out filters - the reason you would need to do this is not because you are adding or subtracting path length (they're inside a filter wheel), but because of small differences in the index of refraction of the material. The effect is not noticeable on the 5-inch refractor at my club's observatory (I checked with a Bahtinov mask), but perhaps it is much more noticeable on something with the far longer focal length of my 11-inch Schmidt-Cassegrain (800mm on the refractor, 1763mm with my focal reducer in place on the C11). Further tests are needed.
I tried the Iris Nebula, Ring Nebula, and Whirlpool Galaxy as well, but didn't have any good blue frames on any of them. The Whirlpool images I took close to morning, so I only got luminance. I went ahead and stacked the luminance frames anyway, so that I'd have something...they came out kind of neat!
Date: 9 May 2018
Location: Prude Ranch, TX - Texas Star Party
Object: NGC 7023 Iris Nebula
Camera: ZWO ASI1600MM Pro
Telescope: Celestron C11
Accessories: Astronomik L Type 2c 1.25" filter, f/6.3 focal reducer, EV focuser
Mount: Celestron CGE Pro
Guide scope: Celestron 80mm
Guide camera: QHY5
Subframes: L: 17x180s
Gain/ISO: Unity (139)
Stacking program: DeepSkyStacker
Stacking method (lights): Median kappa-sigma clipping (2,5)
Darks: 20
Biases: 30
Flats: 25
Temperature: -25C (chip)
Date: 10 May 2018
Location: Prude Ranch, TX - Texas Star Party
Object: M51 Whirlpool Galaxy
Camera: ZWO ASI1600MM Pro
Telescope: Celestron C11
Accessories: Astronomik L Type 2c 1.25" filter, f/6.3 focal reducer, EV focuser
Mount: Celestron CGE Pro
Guide scope: Celestron 80mm
Guide camera: QHY5
Subframes: L: 4x60s
Gain/ISO: Unity (139)
Stacking program: DeepSkyStacker
Stacking method (lights): Median kappa-sigma clipping (2,5)
Darks: 19
Biases: 30
Flats: 1: 20, 2: 0
Temperature: -25C (chip)
Date: 10 May 2018
Location: Prude Ranch, TX - Texas Star Party
Object: M57 Ring Nebula
Camera: ZWO ASI1600MM Pro
Telescope: Celestron C11
Accessories: Astronomik L Type 2c 1.25" filter, f/6.3 focal reducer, EV focuser
Mount: Celestron CGE Pro
Guide scope: Celestron 80mm
Guide camera: QHY5
Subframes: L: 12x30s
Gain/ISO: Unity (139)
Stacking program: DeepSkyStacker
Stacking method (lights): Median kappa-sigma clipping (2,5)
Darks: 20
Biases: 30
Flats: 20
Temperature: -25C (chip)
Date: 9 May 2018
Location: Prude Ranch, TX - Texas Star Party
Object: M104 Sombrero Galaxy
Camera: ZWO ASI1600MM Pro
Telescope: Celestron C11
Accessories: f/6.3 focal reducer, Astronomik L Type 2c 1.25" filter, EV focuser
Mount: Celestron CGE Pro
Guide scope: Celestron 80mm
Guide camera: QHY5
Subframes: L: 31x180s
Gain/ISO: Unity (139)
Stacking program: DeepSkyStacker
Stacking method (lights): Median kappa-sigma clipping (2,5)
Darks: 20
Biases: 30
Flats: 25
Temperature: -25C (chip), 50-58F (ambient)
If you look carefully in the Ring Nebula image, at about the five o'clock position, you can see a small galaxy! Awesome!!
On the other hand, the AVX was working great. Of course, it had a very light load with my Borg riding atop. Guiding in declination wasn't going so well on that one either earlier in the week, but the answer was much less mysterious: the wooden dovetail bar that is currently on the Borg clamps is very short, and especially after I attached the SBIG ST-8300M I'm borrowing to it, along with a filter wheel, it was heavily unbalanced. So, I got creative...
I first grabbed some duct tape and wrapped the little Orion 10x42 binoculars on it, but it wasn't quite enough, so I grabbed a few waterbottles from the car and strapped them on too. It still wasn't enough, but it was much better! Guiding looked somewhat better. And with a scope with such a wide field-of-view, it's pretty forgiving of small errors.
Poorly-balanced guiding
More well-balanced guiding
With such nice guiding, I got a full set of LRGB images using the ZWO filters I borrowed from my minion Miqaela, since she was still DSLR imaging, on part of Markarian's Chain, centered on galaxy M86. Markarian's Chain is a portion of the Virgo Cluster of galaxies that makes this neat long chain of galaxies that is fun to follow in a big juicy Dob. The large FOV of my Borg can capture a fair amount of it. My last attempt at least year's Texas Star Party came out very noisy, mainly due to the fact that I was borrowing Miqaela's Nikon D3200, which we later discovered while I was taking dark frames on it had an unusually high noise profile. Like, the dark frames were nearly totally red and white! This time, the SBIG was cooled to a frosty -15C, which gave it significantly less noise.
Date: 10 May 2018
Location: Prude Ranch, TX - Texas Star Party
Object: Markarian's Chain
Camera: SBIG ST-8300M (borrowed)
Telescope: Borg 76ED
Accessories: Hotech field flattener, ZWO LRGB filters 1.25"
Mount: Celestron AVX
Guide scope: Orion 50mm mini-guider
Guide camera: QHY5IIL-Mono (borrowed)
Subframes: L: 10x300s
R: 8x180s
G: 7x180s
B: 10x180s
Total: 35 frames, 2h5m total
Gain/ISO:
Stacking program: DeepSkyStacker
Stacking method (lights): Median kappa-sigma clipping (2,5)
Darks: 30 (300s), 30 (180s)
Biases: 0
Flats: 0
Temperature: -15C (chip), 62-68F (ambient)
There are a ton of galaxies in this image! Check out this inverted black and white version to detect more...basically anything that has a smudgy appearance is probably a galaxy.
Check it out on AstroBin for a version that has many of them labeled.
After I got through all of that imaging, I had a little darkness left around 4 AM, but only got a few luminance frames on the Western Veil Nebula before the moon came up and it was time to turn in.
My third project for the evening was the reason I took my Nikon D5300 off of my Borg - I took a lot of timelapse images that week, and wanted to do some long exposure on the Milky Way. I took the Vixen Polarie and the Nikon up to the upper field and took several minute-long images across the sky to make some panoramas.
My Nikon D5300 attached to my Vixen Polarie. It's in a flat position for the panning daytime timelapses I was taking, but for night sky imaging, you angle it so it's pointing at Polaris, using a small hole in the side. (It can also be used in the southern hemisphere, pointing at the southern pole, with a switch flipped).
While I was up there, I apparently missed club member Bob making some of his famous scrambled eggs. I can't believe it! However, the panoramas came out so awesome, it might have been worth missing the eggs...maybe...
If I wasn't typing this on my desktop, I'd include that one emoji with the stars for eyes here...I'm so excited about these images! They came out a little distorted from Photoshop's Photomerge tool, but I just need more practice taking them. And I think I might even have some airglow in the bottom image, which is from molecules in the upper atmosphere releasing energy absorbed during the day as greenish and reddish light. You can only see it in very dark locations. In the second image as well, you have three planets - ruddy Mars on the left, bright Jupiter on the right, and dim Saturn in the middle, just to the left of the main bulk of the Milky Way. The top frame is four frames mosaic'd, and the bottom image is seven. :D:D:D:D The skies were truly wonderful!
This was another late night in a long line of late nights - I climbed into my sleeping bag at 5:45 AM. Another (mostly) excellent night!
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