5. TIME VARIATIONS OF THE SENSITIVITY

Unlike the sensitivity calibration for cycles 1-3 (Lindler & Bohlin 1994), there is no significant variation in sensitivity with time, except for the red side H19 and L15 gratings (Figure 2). From the period of February 1994 through July 1994, red H19 shows ~2% loss of sensitivity, which is followed by a gain in sensitivity of up to 8% in the 1900-2000Å region during the period of August 1994 to July 1995. The models for the red H19 and L15 corrections evaluated at 0.3 year intervals are shown in Figure 3. Except for red H19 and L15, the pipeline processing will use the average sensitivity curve with no time corrections for FOS observations taken after the first HST servicing mission in 1993 December.

[Previous] [Next] [Up]

Generated with CERN WebMaker