[Issues] external bad pixal masks

John P. McFarland mcfarland at astro.rug.nl
Thu Dec 13 11:46:47 CET 2007

Hi Johannes,

As you know, the WeightFrame in Astro-WISE is created by deriving many 
different bad pixel maps (for hot and cold pixels, saturated pixels, cosmic 
ray bad pixels, satellite track bad pixels, etc.) and combining them with a 
flat frame.  Support for an external bad pixel map is certainly possible, 
but I think that it was omitted because there is no possibility of a proper 
history for such a map.  If such support would be integrated into 
Astro-WISE, it would have to be in the form of a new persistent class and 
have very strict guidelines for creation.

I have sent this reply to the issues list as well to prompt a discussion on 
this point by those more familiar with history of bad pixel maps in 



On Thu, 13 Dec 2007, Johannes Koppenhoefer wrote:

> Hello John,
> I found some pixel in the WFI chips to smear out count in y-direction. 
> these are not detected in ColdPixelMap because if you smear out something 
> homogeneous like a flatfield it will still be homogeneous. Also the pixels 
> do not show up in HotPixelMap. Is there any functionality in AW to apply 
> an external bad pixel map? I helped myself tweaking my 
> ReducedScienceFrame.py and using a masking program I wrote, but I think in 
> the long term a clean implementation would be better.
> Maybe there is already something?
> Cheers,
> Johannes

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