SNR calcs

[brandx]

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

[karenacollins]

Are your detector read noise, dark current, and gain settings correct in aperture settings?

Karen

[brandx]

Yes - as per FITS header and read noise from instrument data

[karenacollins]

Send me an email with your measurements table and an image showing the target star and how the aperture is position on it. Make sure the aperture and sky annulus are both showing.

Karen

[brandx]

I have emailed you concverning some additional issues arising