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Removing Moon Halo from DSO Image

Astrophotography DSO Imaging
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#1 fyferoni

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Posted 28 February 2024 - 11:35 AM

Hey CN!

 

(Maybe) quick post-processing question:

 

I shot the Pinwheel Galaxy during a 3/4 moon (i've been desperate to get anything imaged, it's been rough here clouds-wise), and after stacking I noticed a prominent line across the image from (what I assume) is the glare from the moon. I have a photo linked below that shows the halo after I removed the BG gradient in Graxpert. The pinwheel was 64 degrees separated from the moon, so I thought that maybe it was enough to minimize light interference. Looks like I thought wrong!

 

I'm not too broken up about it, as it's not super bright, but I was wondering if anyone had any quick post-processing techniques that you use to reduce/remove halos like this (if you even can). 

 

Gear: In my signature.

 

Lights info: 120s exposures (about 8hrs total integration) at 100 gain.

 

Editing platforms:

  • Stacked in Siril
  • Graxpert for gradient removal
  • Post-processing in Photoshop (with star and noise xterminator).

Attached Thumbnails

  • Screenshot 2024-02-28 092611.jpg


#2 bobzeq25

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Posted 28 February 2024 - 11:42 AM

You've done what you can by using Graxpert.  There are alternative gradient reduction tools (I use ABE or DBE in PixInsight), but none that will make a big difference.

 

When the Moon is out I do star clusters.  Maybe gather Ha data from emission nebulae.  For other targets I wait for a relatively Moonless night, the poor data I can get is not worth the effort.


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#3 DanMiller

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Posted 28 February 2024 - 11:49 AM

I hear you about the cloudy skies and the moon.  I just went out and removed my camera and lens from my mount.  Doubled up on my cords holding the tarp that covers it.  We are to get high winds tonight.  As I said, I feel your pain about the weather and the moon. 

 

Dan


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#4 Borodog

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Posted 28 February 2024 - 12:03 PM

Something to try:

 

Make a starless version of the final image. Heal out the galaxy and any other real structure you don't want to eliminate. Blitz the result with NoiseXTerminator on 100%, 0 detail. Scale the result linearly to fill the dynamic range. Divide the final image by the result. What you're doing is making an artificial flat to correct the ring.

 

Good luck.


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#5 Borodog

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Posted 28 February 2024 - 12:03 PM

Or, don't worry about it because nobody will notice the ring if you don't point it out. ;O)


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#6 fyferoni

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Posted 28 February 2024 - 12:25 PM

Something to try:

 

Make a starless version of the final image. Heal out the galaxy and any other real structure you don't want to eliminate. Blitz the result with NoiseXTerminator on 100%, 0 detail. Scale the result linearly to fill the dynamic range. Divide the final image by the result. What you're doing is making an artificial flat to correct the ring.

 

Good luck.

Great idea! I imagine that would be much tougher if I was working on an Ha region or nebula, but with the galaxy that would be much more manageable. Thanks!


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#7 Borodog

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Posted 28 February 2024 - 01:08 PM

Great idea! I imagine that would be much tougher if I was working on an Ha region or nebula, but with the galaxy that would be much more manageable. Thanks!

Will be very interested to see how it works out. Please post an update.



#8 fyferoni

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Posted 29 February 2024 - 10:24 AM

Will be very interested to see how it works out. Please post an update.

How does this feel?

 

https://astrob.in/qjy6v2/0/


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#9 Borodog

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Posted 29 February 2024 - 11:36 AM

How does this feel?

 

https://astrob.in/qjy6v2/0/

Looks great! Did you use my approach to fixing the ring?



#10 idclimber

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Posted 29 February 2024 - 12:02 PM

I would try going back to the starless version. Preferably back before you stretched anything. All this would be done in PixInsight, but I am pretty sure something similar can be done in Photoshop. 

 

1 Clone starless image. Use the clone stamp tool and a large brush and copy the noise from one location in the image to the line. You do not have to have nice soft edges and you do not care if you bump into the galazy. You are only creating a corrected area under the line for use later. 

 

2 On the original starless image create a GAME mask of the line. Here is where you need to cover all the areas that you want to go away and nonce of the areas in the galaxy. Use the convolution tool to soften the edges. 

 

3. Using the inverted mask, blend the image in step 1 to the original. This should only apply to areas that have the GAME mask. There are some really cool tools that just came out for blending images. I would try them. The old way was to use Pixel Math. 

 

Alternate method. 

 

Post the raw integration to a shared drive and let the crew here give it a go and hopefully show you how it was done so you can learn and replicate the results on your own.




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