EFOSC2 

ESO Faint Object Spectrograph and Camera
 
 
  
CCD#40 Cosmetics
Bad Pixel Map

Shown below is a map of the bad pixels on CCD #40. This plot was generated in the following way:
  • High intensity normalised flatfields in each of the UBVRi bands (binned 2x2) were filtered to distinguish 2 groups of pixels
  • [ CCD Bad Pixel Map ]

    It may be noted that the above procedure exagerrates the extent and hence  improves the visibility of each bad pixel cluster. This was needed to make them visible on a compressed plot. The number of bad pixels in any single filter will be less than in the above combined plot. Further, a rather conservative limit has been chosen to define "good pixels" (within 15% of unity gain).

    The Point is: CCD#40 has (but is not just) a pretty face!  Apart from a sprinkling of bad pixel clusters, most of which are just 1-5 pixels in size, all the others are concentrated either on 3 (and a quarter) columns or are  on the margins.

    A more detailed view in each individual filter may be had by downloading the following files :

    However the above files are between 2 and 3 MB in size.  Listed below is a filtered version of the same (to change real numbers into a small set of integers to reduce the size drastically) which are between 10 and 45 KB in size. The intensity code in the images is as follows :
     
    Intensity range on the flatfield Corresponding value on the Filtered Image
    < 0.55
    5
    0.55 - 0.65
    6
    0.65 - 0.75
    7
    0.75 - 0.85
    8
    0.85 - 0.95
    9
    0.95 - 1.05
    10
    1.05 - 1.15
    11
    1.15 - 1.25
    12
    1.25 - 1.35
    13
    1.35 - 1.45
    14
    > 1.45 15

    Send comments to : ls-spectro

    Last modified: Tue Jan 15 20:06:39 CLST 2002

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