Different noise between darks and lights

[GH-ATIK]

Hi,
In the last time, I observe a different noise, when I compare a dark and a light with same conditions.
Here a sample for Atik383L+ : -20°C 1200 sec : ( Histogram manually stretched to same value )

http://www.gerhard-henning.de/Astro%20-%20signiert/light+dark.jpg

Therefore, the processingsoftware had strong problems to remove hotpixels, especially, wen the lights were dithered :

a sample :

http://www.gerhard-henning.de/Astro%20-%20signiert/Artefakte.jpg

The Question :

Is it normal, that the camera produce more hotpixels , when photones meets the chip ?

Thanks

Gerhard

[NickK]

I can't comment on FITS work however usually hot pixels aren't a problem by using darks and flats (to correct scope aberrations) to preprocess before stacking. I use PixInsight with images from my 383L where in addition to processing with darks etc it allow supports Sigma stacking to remove moving image components.

I know from experience that the 383L is sensitive to low voltage power supplies. I use a 13.8V 7A power supply or a Bosch S5 100Ah car battery in the field to prevent low voltage from causing additional noise.

[GH-ATIK]

Hi Nick,

Thank´s , but I tried out Pixinsight, but it works, in this case not acceptable.

I heared, that 383L+works better with higher voltage, I use 12,6 V.
In original specifications on atik-website is a value of exakt 12,0 V.

What is the best power supply with the best noisevalue ?

Thanks

Gerhard

[Chris]

Did you apply flat fields?  Pixels can vary in sensitivity as well as having variable dark current and the plat field should account for that.

This image processing (bias, dark and flat fields) needs to be applied to the light frames before they are registered of course.  Most processing applications should do this.

Chis

[GH-ATIK]

Yes, I used flats,

Gerhard