Thanks for the feedback, everyone.
I'm not using any filters. With 150mm aperture at 750mm focal length (f/5 newt) I only just get enough light, after going through the ep and lens, to make for a decent 1/50th shot at f/5.6. I find it necessary to stop down to f/5.6 to get a sharp shot with the G2's lens, and with ISO 50, there's an obvious cost in that. Filters, or using a clear-aperture mask to reduce contrast loss from the spider would be too long of an exposure.. unless I put more time into the mount and tracking accuracy (this shot was done without lunar or sidereal tracking at all), plus concern over any wind vibrations and such. Starts to become more of a hassle, like deep sky objects, at that point.
I did do some multi-pass USM at the end in photoshop, before exporting to jpeg, which I forgot to mention in my initial post. Helps bring things up a bit.
Getting critical focus is a pain in the ass, I experimented with AF and infinity back when I started and had no luck with it, so I devised a complex method that has worked for me. If the AF/infinity works for you, I'd stick with that
. The smartest way, for my usage, would be to use a laptop and a remote-trigger program, so you could see a 1:1 display of the image taken on a decent sized screen. I don't have a laptop right now, so I make do with the tiny onboard screen. I do the following:
1) Get the object located and centered. Then put the camera on the scope.
2) Get as much zoom as possible on the camera (within diffraction and useful atmospheric limits.. something reasonable) then set the camera's "manual focus" in the middle of the range, roughly. It helps to have picked something of fairly high contrast in the center of the camera's screen, like a crater.
3) Use the main telescope focus to get a ballpark, as close as possible, of something that looks sharp. Kudos if you have a Crayford style focuser, or better yet, one with dual speeds (I have neither, old rack-and-pinion). If need be, use the MF on the camera to pop up the "super zoom" view that it gives for MF usage. It's rather a pain to keep this enabled on the G2, you have to keep the MF button held down, and then separately fiddle with the main telescope focus.
4) Once the telescope focus is as close as humanly possible, then use the camera's MF to further tweak focus (again, on a high-contrast target) to get it as close as you can. The G2's little screen and low resolution makes this a challenge of deciding if 10 pixels look "sharper" than they did before, but experimentation and experience shooting can result in something decent.
5) On the G2, the support for RAW processing on the camera kind of sucks, it only does a bare-minimum-quality JPEG conversion, so if you want to "zoom" in on a resulting raw photo to check focus across multiple high-contrast targets, it doesn't really work. So I usually shoot a high quality jpg, and then use that as a zoom-check to see how the target looks overall.
6) With a maksutov-cassegrain this shouldn't be as big of an issue, but newtonians have serious coma without a corrector like a paracorr (which I can't currently afford). Thus, only the center has particularly good focus, and it transitions out to mush from there. I do the best I can in the middle region, and try to process for the best overall sharpness later using composites of a lot of regions (hence all the images).
So, again, if one had a laptop and a remote-trigger app (like the many that support Canon stuff), this would all be a lot simpler and more powerful, especially for DSOs and stuff. Focusing on lower-contrast items is a gigantic hassle for me, at present.
The images here were all shot with full zoom (only 3x on the G2) into the 17mm Hyperion. I experiment with different options, usually. Last night I also tried it at full-wide with a 2.5x barlow, which made for a better FOV on the lens, but a mushier image with some added CA fringing, so I went back to just the zoom.
Seeing is always the big challenge for me as well. Wisconsin has terrible seeing. Last night was the best I've
ever seen. Visually I was able to push up around 250x, and see tiny shadow detail of the mountain ranges cast over interior detail in craters.. I've never seen that before, at least on the Haemus range. My camera gear was not able to approach that before going to mush (too many elements and BS in the way), so I shot this at.. at whatever the mag works out to (haven't ever bothered to check, 150x or so I would guess).
Thanks again for all the kind words, everyone
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