New script: ScreenStars

[rwoodin3]

Bill Blanshan and I have released a new script designed to help add and remove stars from images. The script features a preview window so you can see what you are doing! The basic approach is the commonly used screening and unscreening methods, however, we have incorporated an additional option for non-linear data which is to incorporate a "reverse stretch" so that removal and addition is done a 'pseudo-linear" image. This really helps preserve star colour, especially when the starless image for recombination is in a very different colour palette to the image from which the stars have been derived. Bill has created a video explaining the use of the script on his YouTube channel: AnotherAstroChannel. You can obtain the script by adding the following url to your repository list: https://www.cosmicphotons.com/pi-scripts/screenstars/.

Clear skies, Mike
(Visit my website for more PixInsight scripts)

Hi, Maybe it's just me being obtuse, but I can not figure out exactly how to create the first instance of a starless image, from an original image that contains a DSO and stars, using Screen Stars.
Starnet2 is crashing in my latest build PixInsight Core 1.8.9-2 Ripley (x64) (build 1601 | 2024-03-01).
I did create a starless image of an existing nebula picture with Starnet2 standalone GUI app. I then selected in the Screen Stars script; Star Removal, with the Reverse Stretch box checked, then loaded original image into the Starry View, loaded starless image created w/ Starnet2 standalone into Starless View, finally entering the text "star_mask" , with Create New Image checked in the output field. That works great, but the reason I installed this script was to create brand new starless images from starry images, so I can process the nebula or galaxy, and then recombine them both back together.

So, my number one question is - does Screen Stars support the creation of a starless image from a preexisting image with stars in it? Thanks in advance for any information on this subject.

 

[Mike1485]

Hi, Maybe it's just me being obtuse, but I can not figure out exactly how to create the first instance of a starless image, from an original image that contains a DSO and stars, using Screen Stars.
Starnet2 is crashing in my latest build PixInsight Core 1.8.9-2 Ripley (x64) (build 1601 | 2024-03-01).
I did create a starless image of an existing nebula picture with Starnet2 standalone GUI app. I then selected in the Screen Stars script; Star Removal, with the Reverse Stretch box checked, then loaded original image into the Starry View, loaded starless image created w/ Starnet2 standalone into Starless View, finally entering the text "star_mask" , with Create New Image checked in the output field. That works great, but the reason I installed this script was to create brand new starless images from starry images, so I can process the nebula or galaxy, and then recombine them both back together.

So, my number one question is - does Screen Stars support the creation of a starless image from a preexisting image with stars in it? Thanks in advance for any information on this subject.

I'm afraid ScreenStars can only create a starless image for you if you have a star removal process (Starnet2 or StarXTerminator) available in your PixInsight installation. It can then interface with that to produce a starless image for you. The script itself does not offer an inbuilt star removal capability.

 

[rwoodin3]

I'm afraid ScreenStars can only create a starless image for you if you have a star removal process (Starnet2 or StarXTerminator) available in your PixInsight installation. It can then interface with that to produce a starless image for you. The script itself does not offer an inbuilt star removal capability.

Thanks so much for the quick reply. I can rest easy, after collecting M109 data all night, knowing it wasn't something I was overlooking.
Screen Stars script is still well worth having, owing to it's improved star extraction\recombination method.

 

[TurtleCat]

@Mike1485 I ran into an odd bug with Star Replacement mode. It's saying that there are no views specified but clearly there are and then when I cancel the dialog (since nothing happens) it says the image ID isn't valid. I tried renaming image IDs and it didn't change anything. I also quit PI and reloaded the project and tried again and it still has a problem. I can work around it but perhaps there is an issue or an error message could be provided?

Also my feature request above is still something I'd like to request.

The first image is what happens after I click to run the script. The second is the console after I cancel (I've waited as long as a minute to see if it would finish)

 

[Mike1485]

@Mike1485 I ran into an odd bug with Star Replacement mode. It's saying that there are no views specified but clearly there are and then when I cancel the dialog (since nothing happens) it says the image ID isn't valid. I tried renaming image IDs and it didn't change anything. I also quit PI and reloaded the project and tried again and it still has a problem. I can work around it but perhaps there is an issue or an error message could be provided?

Also my feature request above is still something I'd like to request.

The first image is what happens after I click to run the script. The second is the console after I cancel (I've waited as long as a minute to see if it would finish)

View attachment 22555

View attachment 22556

You can ignore the messages saying that views are not specified. The issue is with the new image id specified. I suspect there is a space character in the name either at the start or the end of the name - please check this and see if that resolves the issue. Clearly the script should not crash as a result of an invalid id - I will make sure this is caught and handled appropriately in the next release.

 

[TurtleCat]

You can ignore the messages saying that views are not specified. The issue is with the new image id specified. I suspect there is a space character in the name either at the start or the end of the name - please check this and see if that resolves the issue. Clearly the script should not crash as a result of an invalid id - I will make sure this is caught and handled appropriately in the next release.

Ah, I didn’t look to see if there was an invisible character in there. I’ll test it again with my project later today. I bet you’re right and thank you for fixing it!

 

[Mike1485]

Ah, I didn’t look to see if there was an invisible character in there. I’ll test it again with my project later today. I bet you’re right and thank you for fixing it!

I have released v1.2 today which will now test for a valid view id before applying and decline gracefully if it is invalid! Also the new version has different new view ids depending upon whether you are extracting stars or combining.
CS, Mike

 

[TurtleCat]

I have released v1.2 today which will now test for a valid view id before applying and decline gracefully if it is invalid! Also the new version has different new view ids depending upon whether you are extracting stars or combining.
CS, Mike

Fabulous, thank you! My only other suggestion would be some way to set up a process icon with the script that retains which mode it’s on. But that is a very minor nice to have.

 

[Mike1485]

Fabulous, thank you! My only other suggestion would be some way to set up a process icon with the script that retains which mode it’s on. But that is a very minor nice to have.

Thanks for raising this. In version 1.3, just released, the new instance triangle will now create an instance storing all current parameters including the mode.
CS, Mike