Need some help, if possible.

[Stuart1971]

4 minutes ago, The Lazy Astronomer said:

Seperate bias frames should not be necessary as the bias signal is contained within the flat darks. 

For information though: the ZWO version has a minimum exposure time of 32 micro seconds, I assume the QHY one is the same. With my ZWO cameras, if I set the exposure time to 0 in the capture software, the camera will use the shortest possible exposures. Again, I assume this would work the same with QHY.

And what length are your flats mine were 5.6 seconds and dark flats to match, is this ok…?

[tomato]

Despite a recent thread on here arguing the contrary, I am still going with dark flats on CMOS cameras, rather than bias frames. 

[The Lazy Astronomer]

3 hours ago, Stuart1971 said:

And what length are your flats mine were 5.6 seconds and dark flats to match, is this ok…?

I have a different camera to you, but generally my flats are in the 3 - 10 second range. I'd imagine there's nothing wrong with what you've done, but the real test of whether a flat is ok or not is to answer the question: does it properly calibrate the lights? Yes = good flat, No = bad flat.

[Stuart1971]

@vlaiv can you interpreted this figures for me from a recent stack in APP, no calibration frames just the lights, not sure on what the SNR figures are and if they are good or not, this was using Mode 1 and gain 56, 5 min subs..

thanks

[vlaiv]

@Stuart1971

I'm not sure that I can. I don't use APP so have no idea what those might be.

Single SNR value that relates to whole image just does not make sense. If we have uniform signal - like single pixel or extent of nebulosity that is all the more or less the same signal (like faint tidal tail or arm of the galaxy) then it makes sense to talk about signal to noise ratio - but image contains wide variety of signal levels - faint stuff, no signal areas, high signal areas in cores of galaxies or in stars, etc ... so single SNR figure applied to whole image is nonsense.

I'm sure that app author created that SNR figure to be meaningful in some way - problem is, we don't really know what he meant and what does it stand for (might be something like - ratio of average signal in the image versus background noise or something like that)

Star shape is number that is probably describing how round star is, although again - I can't really understand what the actual number means. It would make sense for single number to be value from 0-1 so 1 is perfect circle and 0 is effectively a line. Anything in between would be some sort of ellipse (in that case it would be nice to include angle of elongation as well). Here some numbers are higher than 1 and some are smaller. Have no idea what they mean.

Quality is again - some measure of quality of sub that you can use to decide if you want to keep sub in the stack or discard it. Again - we don't really know how it's calculated.