I like to plan out my imaging sessions a bit before I dive into them, when I can. I have been trying to figure out what kind of SNR gives me the noise levels I want for fainter structures, and I am not quite sure what the math is to do that. I ultimately need photon flux (photons per second per unit area, say per arcsecond), however for objects that actually have the data available, brightness is usually specified in stellar magnitudes. Is there a formula that can convert surface brightness in stellar magnitudes to photon flux? Along the same lines, I use an SQM-L meter to measure my skyfog brightness, and that reports in SQMs which as far as I know is also stellar magnitudes...so I assume that once I have an SQM reading, I could convert to photon flux the same way?
Anyway, if anyone knows how to do this, I would be much obliged!