Just nine minutes on M81 and M82

[michael.h.f.wilkinson]

On March 22, I had several problems getting the mount tracking properly, and only 9 out of 25 60s subs  were usable before I switched to another target, and got some decent data. Just out of curiosity I stacked these 9 subs, and was pleasantly surprised with the result

Quite noisy, of course, but still a lot of detail visible

[old_eyes]

Looks good. I am often pleasantly surprised by how good even a single sub looks. I usually do a quick calibrate, debayer and STF autostretch on the first sub, and maybe a couple of other samples in a long run, to check everything is OK, and think “that looks alright”. Then I am slightly disappointed with what the image looks like with an hour of data.

intellectually we may grasp the whole SNR square root thing, but monkey brain still says “Hey! I’ve just spent hours  collecting 100 times more data. How come it’s not a 100 times better image?”

[michael.h.f.wilkinson]

Just now, KevS said:

What aperture were you using? Do you have access to Hubble data?🤣

6" F/5 Schmidt Newton with ASI183MC

 

[JeremyS]

6 hours ago, michael.h.f.wilkinson said:

On March 22, I had several problems getting the mount tracking properly, and only 9 out of 25 60s subs  were usable before I switched to another target, and got some decent data. Just out of curiosity I stacked these 9 subs, and was pleasantly surprised with the result

Nice result. Especially in view of exposure time.