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This month: Scaling Side-2 CCD Dark Frames with Temperature

Due to a failure of the STIS primary (Side-1) electronics, the redundant (Side-2) electronics have been in use since July 2001. The redundant electronics allow larger fluctuations in CCD temperature, resulting in significant variations in CCD dark rate (see ISR STIS 2001-003). Eventually, dark subtraction in the archive pipeline will automatically handle dark rate variations, but for now darks can be scaled manually as a function of temperature.

As a proxy for CCD detector temperature, the CCD housing temperature (CCDHTAV) will be added to STIS science headers. Until this keyword is available, we will maintain a CCD housing temperature log.

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