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I think I found the issue. SX reports a different spectral sensitivity curve than does Sony for the same sensor. Sony's graph is more in line with what I expect.
The peak of the curve is in the gap between Astronomik's red and green filters, which means the red will actually end up more brightly exposed than the green. The blue is also different on the graph, but in both it'd be the darkest and I think the numbers roughly correlate to the background values in the subs I'm seeing.
As for the brighter skies need longer exposures... that's very interesting and goes against what a lot of people say.
As I understand it, the reason to aim for being "sky limited" is because shot noise and target signal both increase with exposure time, but your read noise is effectively static (random, but not increasing with exposure time).
Being fully sky limited means that your background signal swamps the read noise... so at this point if you're sky limited at 1min, 10x1min = 1x10min in terms of SNR on the background.
This is where it gets interesting, and your quotes from Stan seem to be the opposite to what most people recommend?
My question from earlier was why try to be "fully" sky limited in dark skies with a low read noise camera... I'm going to blow out a ****load of stars trying to do that.
Shouldn't I really be aiming to be sky limited on the minimum target value, rather than the background? Maybe add a bit of buffer for ease of processing.
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