I'm trying to understand the meaning of the sky parameter in the EKOS analysis module. I guess it could be mag/arcsec^2 but sometimes I got some doubts. Are there any information available how this parameter is calculated without digging into the sources?
I was thinking of converting it to an SQM measure, but I believe I'd need to know camera gain, and probably need darks and bias images. I decided to keep it simple, but am open to suggested measures.
As a relative matter (e.g. how the sky is improving or degrading throughout the night) the current measure is probably fine. A similar measure from that respect (relative sky conditions) is # stars detected in the main and guide cameras, and guide star SNR.