GHS stretching haze around stars while enhancing IFN in Deer Lick Group

Processing Stretching Artifacts Cleaning Help Needed
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Rabeea Alkuwari avatar
Rabeea Alkuwari avatar

Hi,

I’d like to ask about a problem that I was dealing with for quite a while though it got worse on the latest data im trying to assemble of the deer lick group. while trying to enhance IFN around the group, GHS seems to stretch lots of “haze” around stars as well. I used to deal with this problem around very bright stars however now its all over the place. I’d like to know what might’ve caused this to get worse (is it just weather? maybe accumulation of dust on the front lens?) and how would I be able to clean it up without messing with the faint IFN im trying to show. I’ll attach my L stacked and processed data for reference📷 L.png

Usually i stretch post start removal using StarXterminator

L.png

Mikołaj Wadowski avatar
Mikołaj Wadowski avatar

These halos look to me like you included data with high clouds in your stack or, like you suggested, shot with dirty front lens. Blink your subs to check if none have any clouds in them.

However, I still find GHS to make the stars more hazey/soft, which likely only adds to the issue you’re having. I recommend stretching the stars with a simple HT midtones adjustment.

Were these halos visible in the starless image, or did they only show up when you added the stars back after stretching?

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andrea tasselli avatar
andrea tasselli avatar
You had high cirrus clouds interfering with the imaging so culling those frames affected should give a much cleaner starting point. I don't think dust can do that. If there is a clean separation between star halos and IFN there are ways to reduce those halos but it requires a lot of manual handling.
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Tony Gondola avatar
Tony Gondola avatar

Have you blinked your frames? If it’s high altitude clouds or haze it should be apparent as you flip though the “movie”. You could effectively do the same thing by looking at star counts assuming the haze was variable through the session.

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