Michael’s images are fantastic but I wonder why he doesn’t take more, shorter exposures although I’m not clear what his sub exposures are. It says 15×15 minutes in your description but that is almost four hours so that can’t be right. CMOS sensors have very low read noise and can be read out very fast so doing short exposures is not normally a problem and it allows you to stack statistically to remove sub frame pixels affected by satellite and aircraft trails. My image from here last night:
https://britastro.org/observations/observation.php?id=20251027_224004_df7ddf0b98656b8c
had multiple satellite trails per frame but none are visible on the final stack of 21x30s frames.
Jeager and Rhemann are undoubtedly the best comet images in the world so I must be missing something about their technique. It is unfortunately the case that comet imagers are badly affected by the mega-constellatons since we are imaging with wide-field, fast optics in twilight but there are solutions which don’t involve manually removing trails from each image.
This was discussed in my talk at the recent comet section meeting around 26 minutes in here:
https://britastro.org/video/2025-10-04_Comet_Section/03%20-%20Edinburgh_NDJ.mp4