I set a plan to image NGC7635 and from the acquired images I get the feeling that subs of 240 minutes is too long based on the washed out area of the nebula. At this point I've been using High gain. It's been suggested several times I may want to try using the High Gain Stack Pro and I'm considering it at this point due to the fact that it would reduce downloads to the remote drives and make it easier for downloads to my local system 3,000 miles away. Using the 24" below what would be a logical approach to getting to a reasonable exposure rate to use generally keeping in mind I'll be trying the High Gain Stack Pro approach? I've used CCD cameras, all SBIG, over the past 25 years and still do with my home systems. CMOS is a whole new system and I seem to be resisting changes to old habits. My CCD days had exposures of 300s on fast refractors and 600-1200 on RCs. Finding a workable exposure approach to this system is proving a challenge primarily due to the time difference (3hrs). I usually double the exposure times for narrow-band filters. The remote system is a 24" f/7 RC and equipped with this AC4040BSI. Exposure suggestions for use with High Gain Stack Pro? Can you adjust the number of frames to be combined? I will scan the manual for this as well but thought input from users would be great as well.
The attached image is the result of 15 240 second exposures. Thin on data per my usual hours of data for each color but what I have from last night. The large stars are extremely bright and the top of the nebula lacks any detail compared to that of my CCD attempts.
Hard to tell for sure from a .jpg Steve, apart from the focus appears a little bit off, can you upload a single luminance .fits sub? When I began imaging with a CMOS sensor a couple of years ago after many years of CCD I found the same issue, the CMOS camera had almost twice the sensitivity of the old Kodak KAF8300 CCD that I’d been using the last ten years and I had to reduce the typical exposure times by a half. With a 100mm quadruplet refractor my typical exposure times for broadband filters dropped from six minutes to three and from ten minutes to five for narrow band, and even those times are too long for some targets. I found it easiest at the beginning to take a single test luminance sub in Maxim of the target at the proposed exposure time and then move the mouse crosshairs over some reference stars in the image to read the ADU count and use that information to determine the exposure time to avoid saturation.
