SNR calcs

Posted by brandx on May 23, 2023; 11:35am
URL: http://astroimagej.170.s1.nabble.com/SNR-calcs-tp2244.html

Regarding SNR calculations.  I was using Starlink GAIA to help determine optimal aperture using SNR based on photon counts.  GAIA reported counts and count_err so SNR was simply count/count_err and for similar sized apertures to those in automatically sized in AIJ I was getting ~90 to 100 SNR. The SNR calculation in AIJ appears to be calculated on flux /flux _err so same in principle (assuming counts is equivto flux) but in AIJ the SNR is consistently 0.003 ie error much greater than the measurement.  So I'm not sure how to interpret AIJ SNR calc