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1-star registration, local normalization rejection - interesting star trails

Brown Dwarf Customer
Joined: 11 months ago
Posts: 14
Topic starter  

Attached is a stack of 55 images of comet C/2019 L3 ATLAS from two nights ago.

I used 1-star registration, and also local normalized rejection during integration.

2022 03 24 C2019 L3 ATLAS St 1

Note that the faintest background stars are trailed, which makes sense because the 1-star registration data showed that the comet drifted about five pixels (in the X direction, zero rate in Y direction) during the imaging run. But the brighter stars are not trailed at all.

I presume this is a feature of local normalized rejection? is only invoked above a certain threshold that is defined by the local background level?

Anyway, I just wanted to share this result. (When I first looked at the image I knew something was different, but it took me a bit of time to realize the difference in bright/faint stars that did/didn't trail.)

Galaxy Customer
Joined: 4 years ago
Posts: 2090
Posted by: @tomkrajci

But the brighter stars are not trailed at all.

It is difficult to see with such a strongly compressed image, but the bright stars are trailed as well. Compared to the displayed size of the stars, however, the trailing of the bright stars is much less noticeable than that of the faint stars.