Remove stars but not all of them

S

speleogen

Member
All:
I've got a mono Ha image of the Flaming Star Nebula that I'd like to remove all the stars from except a select few. I've used StarXterminator to remove them all but I have no idea on how to delete most of them and add this back in. Any help appreciated.

John
 
how about making a mask that masks the entire image except for the stars you are interested in, then mask the image and run StarXterminator.

there are a lot of ways to go about this, but one would be to extract the stars, extract the L from that star image, then use clonestamp to erase all the stars you want to eliminate. then undo the starXterminator run, mask the image with your mask, and run starXterminator again. you probably need to invert the mask if you do it this way.

rob
 
pfile said:
how about making a mask that masks the entire image except for the stars you are interested in, then mask the image and run StarXterminator.

there are a lot of ways to go about this, but one would be to extract the stars, extract the L from that star image, then use clonestamp to erase all the stars you want to eliminate. then undo the starXterminator run, mask the image with your mask, and run starXterminator again. you probably need to invert the mask if you do it this way.

rob
Click to expand...
Thanks, I'll give that a try.
 
i guess since its a mono image you don't need to extract the L, somehow i was thinking about a color image.

for clonestamp you can clone your image, then apply the pixelmath expression "0" (no quotes, a zero) to the clone. you can then use that all black image as a source image for the clonestamp (the source and destination image don't need to be the same image.) that way you can get a black "paintbrush" to erase the stars in the cloned star image.

rob
 
If all you want to do is remove the smallest of stars you could use MMT and turn off a few layers and apply this to the stars only image and then re-screen that back in.
 
chris.bailey said:
If all you want to do is remove the smallest of stars you could use MMT and turn off a few layers and apply this to the stars only image and then re-screen that back in.
Click to expand...
But be careful. Because of the way SXT "unscreens" stars this will not get you back where you started for bright stars if you use the unscreened stars image from SXT. If you use this approach I would suggest you generate the starless image in SXT without the unscreened stars option checked. Then create a stars only image using PixelMath and the following expression: rescale(<original image id>, <starless image id>, 1) - replacing the angle brackets with the ids of your images. Then use MMT and recombine using PixelMath as follows: combine(<starless image id>, <stars image id>, op_screen());
 
Wow. I can see I'll be busy for the next few days. I had never even heard of clonestamp. Fortunately there is a video tutorial on it.
 
Mike1485 said:
But be careful. Because of the way SXT "unscreens" stars this will not get you back where you started for bright stars if you use the unscreened stars image from SXT. If you use this approach I would suggest you generate the starless image in SXT without the unscreened stars option checked. Then create a stars only image using PixelMath and the following expression: rescale(<original image id>, <starless image id>, 1) - replacing the angle brackets with the ids of your images. Then use MMT and recombine using PixelMath as follows: combine(<starless image id>, <stars image id>, op_screen());
Click to expand...
Just an update; this worked reallllllly well. Thanks all!
 
You can remove the stars with Star Xterminator then using histogram transformation you diminish the stars to your liking then add the stars back using pixel math. Seems much easier than the above. If there is a downside to this method please let me know.
 
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