satellite and hot pixel track suppression in software

Started 2 months ago | Discussions thread
Alen K
Alen K Senior Member • Posts: 1,291
Re: satellite and hot pixel track suppression in software

hha1 wrote:

Alen K wrote:

The walking noise ( due to gaussian noise spikes) is also virtually eliminated by sigma clipping.

I have my doubts about that, especially if you are limiting the clipping so much. Can you provide a comparison of pure accumulate vs. kappa-sigma clipping that demonstrates that? If you don't feel like proving it to an old doubting Thomas like me, that's okay.

This is exactly the point I made with the two images at the start of this post. The one on which shows the hot pixel trail was with simple accumulation, the other shows the result of accumulation with 3.5 sigma clipping. If one assumes that

The black level is too low on both images to see if walking noise is a problem on either. I think Jared had a good point about that.

Have you tried the worm error and flexing with your setup?

There is none to correct, on either setup.

I don't use a tracker (anymore). My current, highly-portable setup depends on Astrotracer. Random dithering is a natural consequence of how that must be used when creating large stacks (much more work than saner people than I will do). No worm error (no worm gear) and no flexing problems. The camera or lens is mounted directly to a tripod, like this. My other setup uses a Vixen GP-DX Goto mount, so no flexing of that sort even when it is supporting one of my telescopes. Unguided PE is less than 5 arcseconds (when the PPEC is properly trained).

Your highly portable setup looks intriguing. Can you share any results with it to win me over?

All of the wide-angle, deep-sky images (excepting the ones using film) and the nightscape images in my Astrobin gallery were taken with Astrotracer. All were on the tripod I showed in the other image except for the ones at Grand Canyon and the one I did indoors (!) where I used a smaller travel-friendly tripod. Of course, it doesn't really matter what the camera is mounted to. It just has to be sturdy. Astrotracer will work even if the camera is propped up with a rock.

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