July 2020 Part 2 — This Month Through Your Adapted Lens

Started 3 months ago | Discussions thread
Alan WF
OP Alan WF Senior Member • Posts: 2,602
Re: Some Astro Success

You say you didn't see much improvement with stacking, but how many images are you using?

Between 8 and 15. Unfortunately, the clouds were moving fast enough that I really couldn't get many more than that.

Hmm. You should see significant improvement with 8-15 images in a stack. Naively, that's like having 8-15 times longer exposures or working at an ISO that is a factor of 8-15 lower.

I couldn't find much on suggested settings - ISO range, exposure length, number of photos - in the time I had to research, beyond 'more photos are better!' Oh, and talking about star-tracking mounts if you're doing extended sequences. Do you have a recommended set of parameters?

Here is a suggestion for the Milky Way, but I'd expect it work for comets too:

https://www.lonelyspeck.com/milky-way-exposure-calculator/

Caveat: I've never photographed a comet.

Slightly out-of-focus stars often show colours better than in-focus stars. I've seen stacks of images going from in-focus to out-of-focus, without correction for sidereal motion, and each star forms a wedge. These show the colours of different brightness stars quite nicely. Perhaps something to try once you get better weather?

Definitely sounds interesting! I definitely need to get caught back up on sleep first, though.

I've had a quick Google, and can't find any examples just now.

I typically focus using waaaaaay high ISO, live view, and magnified view. I then (try to remember to) switch to a lower ISO for deeper images.

Regards,

Alan

 Alan WF's gear list:Alan WF's gear list
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