Warm Pixels

[hrhett]

Hi All,

Does anyone know how to resolve the anomalies that show up with warm pixels? I've been told that it can be corrected in Dawn but the Subtract and Dark Magic functions both require an additional file input. To rid my final image of these warm pixels any thoughts for what other input should I provide if I only have a single image from that taken?

Thanks in advance,
Howard

[NickK]

Hi,
A set of darks would sort that out. Do about 20-30 dark exposures (where the exposure time is the same as the normal exposure time but with the lens cap on).

I can't advise on Dawn however processing-wise the image frames are stacked (often averaged) then subtracted from each frame before they're aligned and stacked.

Kind regards,
Nick

[hrhett]

Nick,

So for the secondary input file then you're suggesting just covering the lens? I have a Hyperstar/Fastar configuration which would complicate this. What about shortening the exposure time, covering the camera in its entirety or would that have no effect? Can you tell me what software you are using to address this aberration?

Thank you,
Howard

[NickK]

A dark is basically measuring the noise that camera would add during an exposure and read.

A flat is measuring the aberrations of the optical train.


So taking the same length images, at the setpoint temperature with the camera cap on would produce darks. Then take 20-30 images and stack them (no need for alignment) to give a master dark.

Use the master dark to subtract the noise.