Image Capture Length on Jupiter
Updated: Jan 31, 2021
How long a video of Jupiter can you stack in AutoStakkert without smearing details?
After trying out different combinations of shutter speed and gain when capturing Jupiter I moved on to trying out different capture lengths. I used a shutter speed of 10ms and a gain setting of 270. Normally I use a gain of 280 when capturing Jupiter with a 10ms shutter speed, but this particular night it was causing the histogram to push past 100. We were in a drier air mass and the atmosphere was noticeably less hazy than it has been, so that likely accounted for the brighter image.
Anyway, I tried capture lengths of 30s, 60s, 90s, 120s, 180s, and 240s with my ASI224MC camera in my Celestron 8” EdgeHD with a 2.5x Televue Powermate in the imaging train. Then in all six cases, I stacked 40% of the frames in AutoStakkert, then applied the same wavelet settings in Registax. To improve the images a little further, I removed noise with Topaz DeNoise AI which works wonders at removing grain and noise in your images.
You can see the results in the image above. The 30-second capture had the grainiest image, but there was surprisingly little difference between 60s and 240s captures. While hard to tell in the composite, the finest detail that was resolved does start to get blurred out a bit past 120 seconds, but there really is very little loss of detail. AutoStakkert can really handle quite a bit of planetary rotation when stacking frames.
The bottom line is that when the seeing isn’t great and you know that you won’t be able to stack a high percentage of frames, you can do three or even four-minute captures in order to pull enough frames to stack and not have much loss of detail in the final composite.