Sky quality with a DSLR ? added graph

[Malpi12]

This site is interesting
https://pbase.com/samirkharusi/image/37608572&exif=Y
Briefly : he derives m/sq thingy by the length of exp needed to get the histogram (in a jpg not  a  raw) to 50%. He  says the method was calibrated at a dark site but the calibrating device is not specified (or I missed it !)

I wonder if anyone with a sky quality meter has evaluated this or similar camera type measures?

Reason for my interest :
Until now I have relied upon Mk1 eyeball to know how good the night is. However it seems a long time since I saw, unaided, the Andromeda Galaxy or the Rift in the Milky Way. Is it my old eyes or global warming ?!

Also, after playing with fixed cameras on a tripod, my thoughts are turning to a tracking device and sub lengths.

 

Edited November 4, 2022 by Malpi12

[ONIKKINEN]

ASTAP has an SQM measurement tool that is quite accurate. Calibrate a sub, feed it to ASTAP, platesolve it and then run the tool. It will tell you the quality of your skies as measured from the data.

[Malpi12]

15 minutes ago, ONIKKINEN said:

 ASTAP, platesolve it 

 Thanks, yes I tried that but but never got  it to work, even giving it an accurate, rather than approx. location, - still "unsolved" so either it does not  like my non-round stars or I am doing something stupid ! I think I got the cats. downloaded, but perhaps not correctly !  I'll try again with some nice bright stars and shorter exp. , , 

Meanwhile,  any chance someone with a dslr, and meter +/- ASTAP. could try the 50% histo method  

[Malpi12]

A graph of his equation for ease of use 

 

Edited November 4, 2022 by Malpi12