Can I use different size apertures for multi aperture photometry?

Posted by Shannon on Sep 27, 2020; 8:07pm
URL: http://astroimagej.170.s1.nabble.com/Can-I-use-different-size-apertures-for-multi-aperture-photometry-tp1448.html

I noticed after doing a multi aperture run on a stack of images, I could click and change the size of the apertures while they were still on the screen.  i tried saving these resized apertures, but when I reloaded them they were back to the same uniform size again.  I've played around with the feature which lets AIJ change the aperture sizes on its own but unfortunately that won't work for my situation.

What would be helpful is if I could create custom apertures for each one giving them different radii for the annulus, background, etc.

Also, is it possible to have an aperture that is a single radius circle?  It would be wonderful if I could place an aperture with only one radius and mark it as the sky value.  I suspect there's a workaround for this that lets me "trick" AIJ into measuring the background in the center radius but I haven't learned enough about the inner workings of AIJ to know what that would do to the math.  I could use an aperture and then find the raw counts for the center of my "fake background aperture" on the spreadsheet, though... would that be a reasonable workaround to get a pure background measurement from a crowded field?  I could do the remaining calculations and graphs in Excel if needed.

ETA: Forgot one last question.  Is there a way to change the shape of an aperture so it isn't a circle?  I'm working with tiny apertures only 2 to 4 pixels across and it would be great to have a custom shape instead (some of my target stars are near the edge of the frame and are distorted triangles).

Thank you for any advice or suggestions, it's much appreciated.

Shannon Morgan