Processes or tools for removing moon glare?

Questions and answers about processing in StarTools and how to accomplish certain tasks.
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Moonstruck
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Joined: Mon May 16, 2022 10:43 am

Processes or tools for removing moon glare?

Post by Moonstruck »

During a bright or full moon I would still like to be able to get out to do some deep sky imaging. Does Startools have any special tools/processes that work well for removing moon glare? The weather has been really bad here in New England lately and I am extremely limited in which nights are available for imaging, so would like to be able to do some astrophotography on clear nights regardless of the moon phase. If anyone knows of any processing tricks/techniques you can share that would be appreciated.
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admin
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Re: Processes or tools for removing moon glare?

Post by admin »

Moon glare is really Wipe's domain. Of course, stray moon light will greatly add to the noise and make it harder to collect data on faint objects.

However, not all of us can image under pristine skies - we have to get what we can to get. If you find yourself in this situation often, narrowband filters can really help, but this is obviously a hardware solution.
Ivo Jager
StarTools creator and astronomy enthusiast
hixx
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Joined: Mon Sep 02, 2019 3:36 pm

Re: Processes or tools for removing moon glare?

Post by hixx »

Please don't talk weather, it's the same here in Germany.... :-(

I try to get around the noise issue by doing Luminance shots using a Duoband filter which creates the highest signal / shot noise ratio (at least for faint Ha & O3 objects). It's not helpful for Stars / Galaxies, but as they are bright, SNR is less of a problem here. For Color, I shoot the same object again in those precious, clear, low-moon nights. Color does not need as much integration time, as humans perceive mainly Luminance noise
Stack both Luminance & Color stacks using the same reference frame!
Clear Skies!
Mike in Rancho
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Location: Alta Loma, CA

Re: Processes or tools for removing moon glare?

Post by Mike in Rancho »

Hey John,

Well bright moon is like more light pollution, so you need more time on target to get the same as you would without moon. Also you'll be adding a moving gradient.

If you can make some kind of shield to prevent direct moonlight into or across the top of the OTA, that can help some. Picking targets reasonably far away from the moon is good too.

If you have PI for stacking, you might want to consider local normalization, though it'll take longer.

Once processing in ST, since this is galaxy season that can help some too. Consider cropping fairly deeply as needed, both before Wipe and after your stretch, and maybe use an inverted mask in Wipe to protect your galaxy(ies) or clusters from gradient sensing, and jack up the strengths.

Binning will increase your SNR, though you'll have to take into account your sampling and of course that's a balance with how much cropping you have to do.

Kind of all I can think of at the moment. :think:
Startrek
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Re: Processes or tools for removing moon glare?

Post by Startrek »

I image regardless of the moon phase under both B8 and B3 skies down under but only in Narrowband. Broadband imaging is best utilised with little or no moon around especially small faint targets like galaxies
Tips ……
Choose the brighter emission nebula away from the vicinity of the moon ( at least 40 degrees)
Use Narrowband filters ( Mono 6nm down to 3nm or OSC Duoband or Triband )
Use a anti glare shroud on your scope or some sort of shield against moon glare ( camping ground sheet )
Capture loads of data to increase your SNR
Startools Wipe ( amongst other modules ) does a great job of mitigating noise and gradients caused by moon glare

Attached photo of single 3 min sub of Carina nebula outer arm under a 100% moon overhead last night under B3 skies using Antlia 3nm narrowband filter ( Ha filter shown )

I’ve captured 8 hours of data ( Ha , Oiii and Sii ) so hopefully I should be able to process a decent image

Clear Skies
Martin
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dx_ron
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Re: Processes or tools for removing moon glare?

Post by dx_ron »

This past full moon we had a clear night, and I decided to shoot a few hours of NGC 4565. It would be, I think, a best-case scenario for Wiping the moon, as it is fairly bright, small and without much dim extended nebulosity.

Here's what Wipe had to start with (cropped, initial optidev)
before.jpg
before.jpg (566.84 KiB) Viewed 10074 times
The basic 75% Wipe is not too bad, actually
wipe75.jpg
wipe75.jpg (602.56 KiB) Viewed 10074 times
I cranked it up to 90 (I think even 92 or 93 in the version I ended up using). Did it make a great image with 4 hours of data? Not really, but way better than nothing, I suppose:
NGC_4565_67x240s_v2a.jpg
NGC_4565_67x240s_v2a.jpg (450.76 KiB) Viewed 10074 times
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