Re: How do I force photometry on dimmer of two closely spaced stars

Posted by karenacollins on Oct 25, 2017; 9:54am
URL: http://astroimagej.170.s1.nabble.com/How-do-I-force-photometry-on-dimmer-of-two-closely-spaced-stars-tp614p878.html

Unfortunately, AIJ does not currently support different aperture sizes for each aperture. The only way to potentially handle such at situation currently is to offset the non-centroided aperture relative to the faint object (if there is not another object in the way). Would something like the following work for your situation? It's not ideal since it captures more sky background noise than necessary, but seems to work okay for me most of the time.

I hope to someday have time to implement per-aperture aperture sizes, but the option should only be used for very specific cases since theoretically all point source PSFs (especially if near each other) are the same size in an image, no matter the relative brightnesses of the stars. However, sky background swamps for outer edges of faint star PSFs, so do I realize there are situations were this feature would be useful.

Karen