Problem Description:
I am using a Celestron OAG and a ZWO ASI 174 MM mini for guiding. This camera does not have cooling, so the dark frames need to be recorded at the current temperature.
When I want to use my correctly captured darks in the guiding module, I get a relatively unspecific error message saying something like "...now suitable dark frames...". I suspect that this error is related to the recording temperature of the dark frames, which is listed in the table.
In the Dark module, there is an undocumented parameter "T. Threshold:". I assume this refers to an "acceptable temperature range." Is my assumption correct? How should one precisely understand the "T. Threshold"? Where is the reference point for this range? Does it mean a temperature range of +/- the reference point, or perhaps a range from 0 °C to "T. Threshold"? The unit is "°Celsius". For a delta T, it should technically be Kelvin, or at least just degrees. This confuses me a bit.
Does anyone have experience with this or is there a part of the documentation that I have overlooked?

I thank everyone in advance for the discussion and the tips.

ggtux

Gunter,

I *believe* it is the actual CCD temperature's max. allowed deviation from the temperature the dark frames were taken at. If your dark frames were taken at +10°C, T.Threshold is set to 10°C and your actual CCD temperature is +5°C, darks will be subtracted. In case your current CCD temperatur is -5°C, they won't be subtracted. All IMHO.