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Dark current:
For dark current  3x2700sec dark frames were obtained.

The table below summarizes the dark current for each CCD. The derived values are slightly higher than in Test report, but that can also depend on the way this is calculate.

MOSCA dark current (in e-/pixel/hr)
CCD mean sigma
Bottom right 1.5 15.4
Bottom left 0.3 13.7
Top right 3.2 5.6
Top left 2.7 43.9

Fig 1: Median dark frame from three 2700 sec integrations. The gray scale cuts are -5 -- +10 ADUs.


As noted in the test report on the top CCDs there are two patches of high dark current. In the top left CCD the area is roughly x=700-760, y=4040-4078, in the top right CCD the area is roughly x=2056-2080 y=4060-4078. Note also the cluster of hot pixels in the lower right hand corner of the bottom left CCD. The contour plots are a median of three 2700 seconds dark exposure. The contours refer ADUs/pixel/2700s with the interval of five ADUs and the coordinates refers unbinned image.

Back to top Last modified: 19-Mar-2004