Creating Master Calibration Files with QHY8L fits

[Yarosia]

Hello!

I have some trouble creating master dark with QHY8L files.
on the light frames i capture, i noticed the ampglow is not present on every frame. some frames lacks it. Nice because i can attenuate it by using a good frame as reference.
But, when it comes to use dark frames, trouble incomes...
"warning no correlation between the master dark and target frames" happens when calibrating some frames. Both darks and lights are taken by the same software (APT) with the same setting of gain and offset, same duration and temperature.

At the moment i got 21 darks @ -15°C, that match my last image, and the next month images too (until i will be able to reach -20, in mid autumn, winter).
Do i have to redo darks? do i have to discard frames that have/don't have ampglow?

What can i do to minimize the "no correlation" issue?

Thank you very much for any help!

[gvanhau]

Hello

Note the following about the QHY8L cam:

I you take images less than 4 seconds,  It actually takes 2 images, one for the first part of the image and one for the second part of the image and then there is no amp glow.

If you take images of more than 4 seconds, It takes only one image. In this case, there is amp glow because it continues to expose  the second part of the image while reading the first part of it. 
The amount of amp glow is fixed, not proportional to the duration of the image taken.
Because of this, you can not use dark scaling.

Since thermal noise on this camera  is very low,  it is almost the same taking 5 s darks as taking 300s darks, but remember not to enable dark scaling.

Also, when you calibrate flats, you have to take into acount the duration of them....


regards
Geert