Star Removal Techniques - Forums

Topic starter

Jan 11, 2022 · Edited: Jan 11, 2022

I am sure there are tons of discussions elsewhere. But this seems an appropriate first topic for this group.

What are everyone’s go to processes/tutorials/scripts for star removal?

I tend to default to starlet unless it leaves a much of artifacts. Then I will try to use something like Straton. Although straton doesn’t work for drizzled large images. So then starxterminator is my final tool to try.

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Eddie Bagwell

Jan 11, 2022 · Edited: Jan 11, 2022

I used StarXterminator for the free trial and it worked really well. Now I just use StarNet++ in PI and it works pretty good for free but I usually have to do a little clean up in GIMP.

Jeff Bennett

Jan 11, 2022

I simply used Starnet in Pix Insight. I was actually trying make a star mask to boost the signal without blowing out the stars . I had no idea I would the result I did, but I like it. I wish I had more to say, but I do love these images for their artisitic qualities.

Isa's Astrophotography Atelier

Jan 11, 2022

Although I like to have quite some stars in my pictures, I just recently began with the technique as described by Warren A. Keller in the Narrowband chapter of this book "Inside PixInsight". Using a star mask + enhance the mask by making its whites whiter using HT then run Morphological Transformation and Multiscale Linear Transform over the Narrowband images - in my case H-alpha so far. The result was quite good last time and looking forward to hearing more tips from you all. CS, Isa

Danny Lee

Jan 11, 2022

Most of my images include stars but occasionally I'm inspired to process a starless (I've added a couple to this group)

I still do a good chunk of my processing with stars removed though, before adding them back in. I started out using Starnet++, first the stand alone version and then via PixInsight. It worked really well at the time.

I started to see a few videos comparing Starnet++ to StarXterminator , which up until that point I hadn't heard of. I gave the free trial a go and although I was happy with Starnet, StarXterminator did do a better job, at least for my images.

I've since run a few comparisons on my own data and must preferred the results coming out of StarXterminator. There is a catch though as it's £40 where as Starnet++ is free.

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Dale Penkala

Jan 11, 2022

I have not been a big fan of starless images but the more I got to working with them the more they grew on me! I do most of my work now on the starless image before bringing the stars back in with either Gimp or PixelMath in PI. I’m using the Free version of PI now and I’ll say it runs much faster then the stand alone version!
I don’t like the scares or artifacts that is left behind after Starnet is done and have heard about the “Exterminator” in PI. I may have to give it a try as I’m hearing many are using it and feel its far better then Starnet.

I would like to hear more what @Isa's Astrophotography Atelier said about Warren Kellers process. Can you give us more direction???

Dale

Christopher Stobie

Topic starter

Jan 11, 2022

I agree with all you folks, and also generally prefer to retain stars in my images. But damn if I don't also love and appreciate the beauty of starless. It's just totally something different, and I really love admiring them.

Additionally I almost always (except maybe with galaxies) go through a tone mapping procedure of some sort, which involves totally removing stars from my images early on and then adding them back in later after getting colors, hdr, etc.. the way I want it.

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Anthony Fuller

Jan 12, 2022 · Edited: Jan 12, 2022

I totally agree, until recently using Starnet to remove stars from my images, the beauty is just artistic! The images coupled with the right image processing are just breathless! So glad to be a member of this group!

Isa's Astrophotography Atelier

Jan 13, 2022

Thanks, Dale. Just to come back to your question about what Warren A. Keller writes (his book is really excellent and can recommend it): There are several chapters where he talks about star shrinking or removal and I guess there are several techniques. What he recommends is to use a Star Mask that reveals all of the stars. Now this might be tricky but will come back on this later. He also recommends to enhance the mask "by making its whites whiter using HT or CT". I used HT for the H-alpha subs of my Orion Nebula pictures and it worked great except for the big stars. Next you apply the mask to the image and then run MT and MLT. Alternatively, he recommends to try the StarReduction script.

I think it takes some practice and maybe several star masks are needed, then combining them with PixelMath. Found this reference online, tried it today and the result was quite good: http://trappedphotons.com/blog/?p=731

Again, Warren's book is really worth the invested money. I use it always for orientation in PI which can be like a desert or a big anarchy depending on how you look at it in the beginning....

Best wishes,
Isa

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Dale Penkala

Jan 14, 2022

Isa's Astrophotography Atelier:
Thanks, Dale. Just to come back to your question about what Warren A. Keller writes (his book is really excellent and can recommend it): There are several chapters where he talks about star shrinking or removal and I guess there are several techniques. What he recommends is to use a Star Mask that reveals all of the stars. Now this might be tricky but will come back on this later. He also recommends to enhance the mask "by making its whites whiter using HT or CT". I used HT for the H-alpha subs of my Orion Nebula pictures and it worked great except for the big stars. Next you apply the mask to the image and then run MT and MLT. Alternatively, he recommends to try the StarReduction script.

I think it takes some practice and maybe several star masks are needed, then combining them with PixelMath. Found this reference online, tried it today and the result was quite good: http://trappedphotons.com/blog/?p=731

Again, Warren's book is really worth the invested money. I use it always for orientation in PI which can be like a desert or a big anarchy depending on how you look at it in the beginning....

Best wishes,
Isa

Thank you Isa for the info. I’ll have to look into this book. I’m quite new to PI so the book I’m sure could teach me many things!

Dale

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Christopher Stobie

Topic starter

Feb 1, 2022

Updating this thread with the release of Starnet++ v2! My latest Rosette Starless is done using this updated version of Starnet, and I have to say I am very impressed.

Thread here https://www.cloudynights.com/topic/808556-starnet-v2/

Highly recommend following the links as well to setting up CUDA drivers to let your GPU do the processing, 3-5x the speed when compared to CPU.

I am noticing almost no artifacts, no bright nebulosity removed, it's night and day when comparing to Starnet v1. Excited to see other folks thoughts.

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