Hi,
Image scale is the relationship of the focal length and pixel size. Just know that a smaller instrument with a short focal length and a big pixel sensor will have a course image scale, ie, it will be lower resolution, forgiving on seeing conditions, and not ideal for sampling (recording resolution relative to the airy disc). Your 600mm with a 2x TC on big pixels is fine, it will be limited by the 95mm aperture but ultimately limited by the atmospheric seeing for the real resolution potential. Don't worry about it.
Your 90D has 3.19um pixel size, so it will sample visible spectrum (RGB) critically from F12 to F17, so anything in that range will be a good choice. Anything faster (F8, F5.6, F4, etc) will just undersample on your pixel size (lose resolution). Anything slower than F17 will just waste light. Your 600mm at F6.3 with a 2x TC is F12.6 (F13). I would just leave it at F13 (wide open, don't stop down your focal-ratio). If you stop down your focal-ratio in camera, you're closing the iris and masking your 95mm aperture (the actual size of the opening to your lens). So the ideal use of your 150-600 F6.3 is wide open, do not stop down aperture, with a 2x TC for your pixel size.
5ms (milliseconds). I explained it was 1/200s in traditional camera fraction exposure times right after I wrote it.
Your FPS is in video, don't try to do it in still images. You'll just kill your shutter mechanism faster trying to do hundreds or thousands. You don't take still images. You enable video and record video at the fastest FPS it can record at (30 FPS, 60 FPS, 120 FPS, etc). And adjust exposure time to a short value like 1/200s (5ms) so that you freeze motion and seeing as things move.
Gain is your digital ISO. So just turn up your ISO on a typical d/m-SLR.
If you're not familiar with AS!3, there's tutorials on YouTube and lots of resources, its free and highly used. The quality graph displays after you analyze a video of frames and it will weight each frame based on contrast from best to worst and give you a quality graph based on that so you know how many frames are higher contrast relative to the rest so you can choose a more logical amount of frames to align and stack keeping the high contrast ones and not the poor ones. Basically look at the graph after it analyzes it and select how many frames (% or hard value) that have the highest quality weight, such as above 50% or above 75%, etc. It will be few frames. This is why you need many.
Yes, Handbrake is free. It's a video transcoding software. You may need it if your capture file container from your camera is not a typical RAW container (AVI, SER, etc). I know a lot of cameras use MOV and other stuff that may not be read properly by software like AS!3.
You can manually hand track the moon while recording video no problem. Even with an Alt-az mount. It's super easy with a slow motion control manual mount. A tracking mount of course does this for you. But it's not necessary. You can do it with a traditional tripod too, just let the moon drift in the FOV as long as you can. Take video at high FPS while it drifts in your FOV. Do it a few times going for lucky images when seeing moments are good.
Very best,
Thank you Martin! I think I am ok with what you wrote down to "You can manually hand track the moon while recording video no problem."
I believe you are saying to "manually move the "tracking" of the moon while in video mode which will make the video jump quite a bit I believe. The mount I use and love is my Manfrotto 410 Geared Head. I had never heard of an Alt-as mount. I googled it which they seem to be made for Telescopes which I do not own.
I really not am into doing video work, but I am willing to give it a try to get a better more sharp single image. is it possible to change the FPS rate of video?
I would think to make a video of the moon at 1200mm without moving the camera I would only get 2-4 minutes before the moon goes outside the live view of my camera. Should I try using my Geared Head to move the tracking of the moon in my live view?
Thank you very much!
