Image Calibration, Dark frame optimization

[DMouse]

Hi, I have been having issues with my image calibration, in that there are still hot pixels showing up in the calibrated images. I noticed that the dark frame option have an optimization check box. If I uncheck this box then the calibrated images don't have hot pixels, but if it is checked then I get hot pixels. The dark frame I am using is temperature matched via the CCD cooling. I would have thought that the optimization routine would remove the hot pixels?
The images are in HA and all processing done in PI. I didn't use dithering during capture, which would probably remove most of these, but that's another issue.

Clear Skies

Paul

[Juan Conejero]

Hi Paul,

The purpose of dark frame optimization is to yield the best possible SNR in the calibrated images. Often this comes at the cost of under-corrected (and even over-corrected in some cases) hot pixels. However, hot and cold pixels are not a practical problem because they can be removed very easily during the integration phase (if the images are dithered).

I didn't use dithering during capture, which would probably remove most of these, but that's another issue.

This is actually the issue. In such case you can try with CosmeticCorrection, or disable dark frame optimization.