Selection Rejection of Star Flares

Daniel Judge · May 2

I have some frames that have a stellar flare I need to remove in the field of view. I recall there was a method to go about removing them ?

Would anyone have a link or procedure that is recommended ?

I can't upload the image for some reason, so here is the dropbox shared image example of this that I want to try remove.

Dropbox Shared Image

Thanks

Dan

BlockHead · May 2

Hi Daniel,

You can see it also at the top left. It is an arc of scattered light that goes through your field. This means there is a cylindrical surface creating this. It could be from a shiny tube/adapter or it could be a result of not quite perfect baffling. This is a very very faint effect and requires a bright star perhaps near to the field (but not in the field of view).

If this exists in all frames there isn't a mathematical way to remove it.

If it does not exist for example in some color data but not luminance (or the other way around...)

then I do have some solutions.

So first the question... does it show up in ever frame?

If so...surgery on the starless image is probably the best you can do.

-the Blockhead

Daniel Judge · May 5

Yes it does show in the color data as well.

Im wondering if I shift the framing in some exposures to try reduce the flare impact; if that portion of the frame least impacted can be subsituted into the other frames ?

BlockHead · May 5

Yes, exactly. You could make a masterlight from the frames that are less impacted and then use one of several techniques (substitution or normalization (NSG)) to minimize the issue in real masterlight. However, this less impacted masterlight would still need to be of good quality. Our eyes are pretty good at seeing the different in S/N of the noise even if the scattered light is reduced.

-the Blockhead

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Selection Rejection of Star Flares

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