Star removal or reducation

13 replies1.7k views
Bill Mark avatar
I mainly use photoshop and would like to know ways to remove stars totally for a picture. I prefer methods applicable to photoshop but any other methods are welcome. It would be nice also to post before and after star removal.
I am aware of several methods in photo shop that can be used to varying degrees of success.
see http://astrob.in/260167/D/
Scott avatar
Hi Bill.  You can use numerous iterations of the dust and scratches tool in PS to accomplish this.  There are also PS Actions that you can
download at a price or for free to do this.  Not sure if I am allowed to post a link here but if you search the net for "troys astro actions"
you will find the free set of actions that I sometimes use.  Good luck.

Scott
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Bill Mark avatar
Thanks Scott for your quick response. I am aware of the dust and scratches function in photo shop. I was preparing examples of what I currently able to do.
dheilman avatar
Hi Bill, I'm also a PS user.  I recently processed a starless Heart Nebula and have listed my method in post #3 here on CN.
Best,
Destin
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Bill Mark avatar
My star selection is similar to yours, I use "subtract" instead of "difference" and "Threshold" instead  of colour select.
For the rest of the processing I just go straight to content aware fill.
I give your process a try.
Bill Mark avatar
This is the best option for star removal. http://www.zipproth.com/#Straton Good luck with it!

Got a chance to try Straton , used on the default settings. two notes:
1 - works only on mono pictures, so DSLR images need to be separated first.
2 - tried to process a 36Mb D810A image, could not process due size.
will post an image once I get a chance to finish my sample image
Wei-Hao Wang avatar
Has anyone compared results from Straton and results from the Photoshop Dust/scratch method?  The Straton page says the Photoshop method is tedious.  However, one can just pack the procedure into a Photoshop action.  After this is done once, every time you want to do it again, it will be just one click.  So I want to know, in addition to being not tedious, if there is any other advantage in Straton?  Cleaner removal of stars?  More natural look?
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Francois Theriault avatar
I also process in Photoshop and I recently stumbled upon a function that does a decent job on some of images. Simply go to
Filter > Noise > Median and use a radius of about 10. It takes care of most of the faint stars and leaves only the very brightest ones behind.
These can be taken care of with the healing brush with the content aware setting.
It also blurs the data a bit, which is no big deal with the colour information since the sharpness comes from the luminance layer anyway.
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Wei-Hao Wang avatar
I don't think that can work very well. The median filter will remove too much details in the nebulas.
Jeff Clayton avatar
I have used a free program called straton

http://www.zipproth.de/

I have had good results with it. here is an example http://www.astrobin.com/172868/?nc=user
Diego Colonnello avatar
If you use Photoshop you can get Annies astro actions, it has a wonderful action called remove stars, works like magic every time… smile
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Kevin Morefield avatar
I have tried Annie's actions but found that it left a lot to deal with.  So I have taken the brute force approach in PS - spot healing.  This, along with clone stamp for the really hard ones, did a great job on my Eagle nebula shot.  It was a lot of work but the result was very good and I was in control of the process completely.
Andy 01 avatar
I regularly replace NB stars with RGB in Photoshop. Look at almost any of the NB images in my gallery & you can see examples there.
I have used Troys, Annies, JP Metsavianios actions and Straton with differing degrees of success.
Sometimes the subject matter itself makes a difference.
At times Annies is brilliant, other times not so much, with lots of cloning to do afterwards.
Straton is pretty good overall, but like all these methods, we are attempting to replace stars with nebulosity detail that doesn't exist.
it's always going to be a compromise.
Josh Smith and Eric Coles have both posted methods here on these forums that are worth searching up as well.
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Marc avatar
There is a module for Pixinsight now that does this basically at the push of a button: https://pixinsight.com/forum/index.php?topic=13691.0
An example from my data, without further processing: https://www.astrobin.com/full/365182/E/?nc=user
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