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Below are the current calibration products for the HRC Hot/Bad Pixel Maps.
The most recent products are:
The following bad pixel maps are based upon results from calibration source measurements performed on orbit. The "bad" pixel regions are identified by the red areas.
| HRC-I | ||
|---|---|---|
| Model | Plot (Postscript) |
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v2(ASCII) v2(FITS) v1(ASCII) v1(FITS) |
v2 |
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The large extent of the "bad" area on the HRC-I is actually an artifact due to the use of a nominal detector area covering 64 by 64 taps (256 pixels wide each). The actual detector area covers somewhat less than this (from approximately tap 2 to approximately tap 57). Thus the large "bad" area is not indicative of any significant damage or change to the original design and performance.
On March 3, 2002, a new hot pixel appeared near the SW edge of the HRC-I detector. Version 2 of the HRC-I hot/bad pixel files include this pixel, which is indicated in the image files with a blue arrow. Note, however, that this pixel was good until that date, and should only removed if your observation was taken after March 3, 2002. Since the inclusion of v2 in CALDB 2.13 (April 4, 2002), this pixel is removed as part of the standard processing.
| HRC-S | ||
|---|---|---|
| Model | Plot (Postscript) |
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v3(ASCII) v3(FITS) v2(ASCII) v2(FITS) v1(ASCII) v1(FITS) |
v3 |
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As with the HRC-I, much of the bad area for the HRC-S detector is actually an artifact of the coordinate system and the translation from detector to sky coordinates. However, there are several hot/bad areas (more than for the HRC-I) on the central plate near its low V end.
On November 19, 2001, a new hot pixel appeared on the central plate of the HRC-S detector. Version 2 of the HRC-S hot/bad pixel files include this pixel, which is indicated in the image files with a blue arrow. Note, however, that this pixel was good until that date, and should only removed if your observation was taken after November 19, 2001. Since the inclusion of v2 in CALDB 2.11 (December 26, 2001), this pixel is removed as part of the standard processing.
In June 2004, we noticed that the hot pixel area described above had
grown larger in size. This enlargement is first visible in a
calibration observation of Betelgeuse taken Feb 2004 (ObsID 5056). In
the raw-coordinate image on the right, created by Mike Juda from the
level 1 event list for a calibration observation of G21.5-0.9 taken
March 2004 (ObsID 5168), the green rectangle shows the original size of the hot spot, and the red
rectangle shows its current size. Version 3 of the hot/bad pixel map
for the HRC-S, in CALDB 2.28 (August 11, 2004), includes this larger region.
Comments to CxcCal@cfa.harvard.edu
Last modified: 09/27/12
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