JA,
I bow to your knowledge
The reason this became an investigation for me was to determine the impact of the sky background noise in a spectral image.
I have a few calculations which are used and have the Sky magnitude in mag/arcsec^2 as a starting point.
When I look at this in detail the definition of "which star" magnitude is assumed? S(10) standard....a red star or a blue star or what????
https://link.springer.com/chapter/10...40-07615-8_450
Basically I need to end up with the sky background in photons/ sec.
Any comment/ ideas???