CCD Housing Temperature Monitor

Since the switch to STIS CCD Side 2 electronics (see ISR 2001-03) on 2001-Jul-10, it has not been possible to actively stabilize the CCD operating temperature, due to the lack of a temperature sensor on Side 2. Therefore, to control the thermal environment, a constant current is applied to the CCD thermo-electric cooler. This, however, allows small variations in CCD temperature. These variations are tracked indirectly by a temperature sensor in the CCD housing, so that temperature-dependent calibration can be performed.

The following plot shows the history of the CCD housing temperature since the switch to Side 2. The x-axis gives the date in years, while the y-axis gives the CCD housing temperature in degrees Celsius. The dots are the temperatures for each of the CCD observations. The filled diamonds are the medians per calendar month.

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