Re: Subtracting a Galaxy template

Posted by cduston on Nov 08, 2023; 3:46am
URL: http://astroimagej.170.s1.nabble.com/Subtracting-a-Galaxy-template-tp2302p2304.html

Ok great, I figured it out based on what you said.

I did exactly your process (one difference to what I was doing being after creating the template, I opened the stack IN memory, instead of virtual...not sure that matters), but it still didn't work.

I thought it might be the "cut and pasting" of the region, so what I actually did this time was

1. Subtract off the background
2. Circle the galaxy
3. Choose "clear outside"

and use that as a template, and it worked! (Oh, I also did the Process -> "Image/stack calculator" in the "main AIJ window", and not the window that held either my stack or the template - not sure what you meant there, just being complete.)

I still have to work out normalizing the images first (since the galaxy brightness is different in all of them), and the fact that subtracting out the average background leaves some negative pixels in the template image - if anyone has suggestions about that, I'll take them, but my main question has been answered, thanks!

Chris