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Hi Mabula,
this is a crop of my first stack with default settings in AP.
There are some Pattern with red, blue and white Pixels inside
.
I try AHD and the pattern is there too, only less. Kamera is 600da, Filter IDAS LPS-P2
regards
Dirk
Hi Dirk,
These are definitely bad (hot) pixels. By far, the best way to remove these in calibration is by using a bad pixel map:
You'll need a couple of flats (let's say 10) and some darks (use 20-50 ) of exposures of a couple of minutes. (longer exposure lengths for the darks will make a higher quality Bad Pixel Map.)
The Bad Pixel Map is much more efficient in removing bad pixels than using a Master Dark from a set of darks since
- hot pixels don't behave linearly, so a Master Dark will (very likely) never correct all bad pixels perfectly.
- the bad pixel map won't introduce noise since it corrects the bad pixels by interpolation from the surrounding "good" pixels.
I have placed an example of a Bad Pixel Map correction in the creating-a-bad-pixel-map post:
"An example of Bad Pixel correction using a Bad Pixel Map:
a Canon CR2 light frame of 600s exposure length, ISO200, Canon 450D (courtesy of Scott Rosen) corrected with a Bad Pixel Map created out of 100 darks of 600 seconds exposure length.
A crop of the sensor is shown, showing plenty of bad pixels which we want to remove.
Top: uncalibrated Bottom: calibrated
Left: bilinear debayering and no Linear Background Neutralization
Middle: bilinear debayering and Linear Background Neutralization
Right: Adaptive Airy Disc debayering and and Linear Background Neutralization (notice the dramatic increase in sharpness and better star shapes and change of colors 
due to AAD debayer)."
Let me know if you can get rid of these bad pixels 😉
Mabula
Hi Mabula,
thanks. I try too make darks for a Bad Pixel Map. In this case i used dithering, without darks.
Greets Dirk
Hi Dirk,
Dithering combined with an outlier rejection filter (kappa clipping) while integrating should help in removing the bad pixels, but if you can get rid of these in the calibration fase without introducing noise than that's always better.
If you create a good and effective Bad Pixel Map, you'll enjoy this for a long while 😉
Regards,
Mabula
