Dark flats are empty!

[Adolfo De Sanctis]

[X] Is the issue reproducible? Yes
[X] Are you running the latest version? Yes
[X] Are all prerequisites that are mentioned inside the manual met? Yes

Description

Using flat wizard for taking darkflats. The actual fits files are simply all black, with no data in it. If using a sequence to make darkflats the same issue is encountered. Only saving them as lights allows to actually get the data. Using ZWO ASI294MC Pro, did not test on other cameras.

Steps to Reproduce

• Run flat wizard with dark flats activated
• (or) run a sequence with darkflats

Expected behaviour

Darflats should contain at least the same information as in the bias frames.

Actual behaviour

No data are present in the actual fits files, just a completely black file. When running a staking in APP (stacking flats using bias frames and darkflats) get this warning:

WARNING !!! we have detected a possible sensor offset issue between the MasterBias and the Masterdark !
10:41:04 - 2) CALIBRATE: WARNING !!! the MasterBias has a median value of: 7.660E-03 for channel 1
10:41:04 - 2) CALIBRATE: WARNING !!! the MasterDark has a median value of: 4.378E-03 for channel 1
10:41:04 - 2) CALIBRATE: WARNING !!! normally, the median value of the MasterDark should be the same or larger than the median value of the MasterBias
10:41:04 - 2) CALIBRATE: WARNING !!! because a dark should always contain the entire bias signal plus the dark current and possible amp glow signals
10:41:04 - 2) CALIBRATE: WARNING !!! some CMOS sensors however exhibit this behaviour due to CMOS technology

[Stefan B]

Cannot reproduce with ZWO ASI 1600.