Light Pollution Cor...
 
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Light Pollution Correction Tool question


(@cheastside)
White Dwarf Customer
Joined: 2 years ago
Posts: 32
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in the video tutorial, Mosaic Tutorial – Milky Way to Rho Ophiuchi part 1-7 by Mabula,

he works the image from left to right to address light pollution.  is this the approach to be taken for all images, mosaics to single images?  or for single image, ie not mosaics, can we apply the initial five boxes over the entire image to start with?  

 

also, do we only place boxes over areas we think have LP?  Or do we need boxes placed all over the image regardless of whether there is LP in an area or not?

in my image capture attached here, i've done a maximum stretch and increased saturation to 30 and saturation threshold to 0.  i have a LP gradient i believe from right to left.  would i need to place boxes at all in the black areas at far left of image? 

Screen Shot 2021 12 06 at 10.14.07 AM

 

thanks!

This topic was modified 5 months ago by cory freeman

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(@turtlecat1000)
Main Sequence Star Customer
Joined: 6 months ago
Posts: 56
 

The way I've interpreted it, and I could be wrong, is to start with a few boxes in areas that don't have nebulosity or the object of your choice. Run calculate and slowly work your way inwards towards the subject by adding boxes in areas of background. For example, if my object is in the center I'll add some boxes in the corners and sides and slowly add some inwards till I get close to the subject. Once everything looks pretty even I'll save and move on.


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(@vincent-mod)
Quasar Admin
Joined: 5 years ago
Posts: 4690
 

Yes, you stretch to the maximum setting (of the presets on the right) and pick 5 boxes around the image on what you think is background. You click to check the result and then you either clear the boxes to set them properly or continue towards problem areas, not directly on top of them, no big boxes either, just creeping towards the areas that show residual gradient.


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(@cheastside)
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Joined: 2 years ago
Posts: 32
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@vincent-mod and @turtleCat

thanks for responding.  so i could place my initial five boxes as shown in the attached image and then work from that right?

Screen Shot 2021 12 06 at 10.14.07 AM

 


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(@vincent-mod)
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Joined: 5 years ago
Posts: 4690
 

Yes, press calculate to see what it does and work from there. This area is challenging because of all the bright stars and dust, so good luck. 😉


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(@cheastside)
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Joined: 2 years ago
Posts: 32
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Posted by: @vincent-mod

Yes, press calculate to see what it does and work from there. This area is challenging because of all the bright stars and dust, so good luck. 😉

yes, it is!  i have 95 boxes placed so far! :O

Screen Shot 2021 12 07 at 6.39.02 AM

 

This post was modified 5 months ago by cory freeman

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(@vincent-mod)
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Joined: 5 years ago
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95! That shouldn't be necessary. haha Having trouble with uneven gradients?


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(@cheastside)
White Dwarf Customer
Joined: 2 years ago
Posts: 32
Topic starter  

@vincent-mod

following mabulas maticulous example from the video haha.  a lot of light pollution in the right side.  i think i've got it now.  i'll try just a few boxes to compare the two.  


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(@vincent-mod)
Quasar Admin
Joined: 5 years ago
Posts: 4690
 

Ah yes, the pollution model is pretty rigid (so not very flexible). This usually helps users as regular gradients are nice and smooth. But here I think you have some uneven patches and that gets tricky indeed. If you are ok with the result, turn down the stretch and it should look pretty nice I think.


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(@cheastside)
White Dwarf Customer
Joined: 2 years ago
Posts: 32
Topic starter  

@vincent-mod

ya, neighbors left their backyard lights on, each side of me, on the first and third nights. not to mention the flood light across the street.  looking at a normal stretch and saturation it does look pretty good.  thanks for the advice!


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(@vincent-mod)
Quasar Admin
Joined: 5 years ago
Posts: 4690
 

Outsj, I feel the pain coming from the Netherlands. 😉 Cool, happy to help!


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