The plots below all assume that one
is observing in the background
limited case. The exposure time refers to the total on-object exposure time. It does
not include either the exposure time on-sky nor any overheads.
Limiting magnitude versus
on-object integration time, S/N per arcsec²=3
Limiting magnitude versus
signal-to-noise ratio per arcsec², for 1 hour on-object
integration time
