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INDI Library v1.9.5 Released (08 Mar 2022)

Bi-monthly INDI Library released with new drivers and bug fixes.

Physical unit of the parameter "sky background light"

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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?

Many thanks.
KStars 3.5 + astroberry remote
EQMOD, EQ6-R , ASI2600+ ASI178+EAF+ASI120
1 year 2 weeks ago #70872

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Arnold,

The sky parameter is a byproduct of SEP star extraction. Take a look at the Background and Background Map sections for details:  sextractor.readthedocs.io/en/latest/Background.html It is the all-sky RMS background (whole image noise standard deviation).

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.

Hy
AP1100 & Orion Atlas Pro, WO/ZS105 w/Moonlight V2 focus, GSO RC10 w/RSF focus
ZWO ASI1600, Astronomik Filters, ST80, QHY 5L-IIm.
KStars/Ekos/Indi on NUC10 & RPi4 w/SSD -- Ubuntu
Projects: Greedy Scheduler, Terrain, Polar Align, Analyze, Linear Focuser, SEP MultiStar & GPG Guide, FITS autostretch.
1 year 2 weeks ago #70961

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Hy,

Many thanks for this information and the link.
I guess I have to spend some time to get a deeper understanding of SEP and the meaning of the different models and parameters.

Arnold
KStars 3.5 + astroberry remote
EQMOD, EQ6-R , ASI2600+ ASI178+EAF+ASI120
1 year 1 week ago #70980

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