Quote:
Originally Posted by gregbradley
I guess the only way I'll find out is to measure it to know.
When you say bias drift how did you measure it? Did you wait for 20mins for the camera to settle down after it reached its cooling temp?
Did it vary with the ambient temp falling as the evening progressed?
Richard also says bias will be different at the start and at the end of a read out process. So there is a variable there as well. I don't know how you measure that if you can at all.
Greg.
|
I measured the average bias in a selection of frames using the Statistics process in PixInsight. I spent several days collecting calibration frames interleaving bias frames and darks of various durations. I was indoors in a room that doesn't vary in temperature a lot (it is embedded in the side of a hill) and didn't start the calibration run until well after the camera temp had stabilized.
I didn't notice any significant variation in bias from the start to the end of the frames but I'll go back and have a closer look. In PixInsight it is easy to set up previews over different parts of the frame and grab stats for each preview.
Cheers,
Rick.