Hi there, last time I imaged Jupiter I had a play around with the capture settings to see if I could optimise them for my C9.25 SCT on a Celestron Evolution mount, ASI224MC and TV 2.5x PowerMate (which actually gives me about 2x mag).
Jupiter was nice and high, seeing was good, so I captured 3 x 3 minute video streams one after the other, with different frame rates and gain settings to keep the max histogram at about 50-60%. The settings I used are shown below, and the processing was performed exactly the same for each run. I tried stacking 5000 and 10000 frames from each stream, same sharpening in Registax and Photoshop but less work to make the images look "pretty".
Run Gain shutter fps Hist (max) Start time Total Frames
1 315 4.933 ms 202 56% 04:36:31 36460
2 248 10.00 ms 99 50% 04:39:46 18000
3 346 3.329 ms 291 57% 04:44:14 52533
The side-by-side images for 5000 and 10000 frame stacks are below (50% larger than captured size). It appears that the seeing (or the focus) may have dropped for the third run, but it's clear that the amount of noise is significantly higher than for the other two. The 5000 frame stacks are certainly sharper than the 10000 frame stacks, but I was a bit surprised that the noise levels for Run 2 were so significantly lower than higher frame rate captures. I tried reducing the stack sizes for Run 2 even further (2500 and 1500 frames), but there was only a minor increase in sharpness at the expense of significantly increased noise.
Based on this test, it's a close call but it appears that Run 2 is giving me the best result, the lower gain levels obviously produce less noise but the shutter speed is still fast enough to give me good sub-frames with no additional "blurring". File size is also a lot lower with the slower shutter speed, which is not a good reason to use it, but it is a bonus. I might try 150 fps also, but it does appear that 100 fps is a good speed to run with Jupiter (for my setup, ymmv).
Edited by Tulloch, 21 May 2020 - 07:41 PM.