Figure 1:
Average Cycle 4 Sensitivity Curves for the (a) High Dispersion Modes and (b) Low Dispersion Modes. Solid lines are the blue side sensitivities, while dashed lines represent the red side results.PostScript of Figure 1 (164KB)
Figure 2:
Change with Time of Sensitivity with Respect to the Averages of Figure 1. The data for three broad wavelength bins are shown and are connected by different line types. The heavy solid line is the adopted fit. Smaller symbol sizes are used to distinguish thePostScript of Figure 2 (226KB)
Figure 3:
Corrections as a Function of Wavelength for a) H19 and b) L15 Evaluated Every 0.3 Year. For H19, there is first a drop in sensitivity to a minimum around 1994.6 followed by an increase to the current maximum sensitivity. L15 shows a generally increasing sensitivity.Figure 4:
One s rms Deviations of the Individual Sensitivity Curves from the Average Sensitivity Versus Wavelength for Each Mode. For the red H19 mode, the sensitivities are adjusted with the time model (shown in Figure 2) prior to computing the rms deviations.PostScript of Figure 4 (200KB)
Figure 5:
Residual Ratios of the Co-added Spectrum in 10Å bins of Each Star Divided by the Input Standard Star Spectrum. The bin size is larger for the long wavelength portion of the prism data, where the resolution is less than 10Å. A pure hydrogen model spectrum is the standard star for the four WD's (G191B2B, GD71, GD153, and HZ43). The other four standard stars are pieced together from FOS blue, FOS red, and Oke spectrophotometry as described by Lindler & Bohlin (1994) and Bohlin (1995). The six panels in each plot are blue-red pairs of high dispersion gratings, low dispersion gratings, and prism modes, respectively. Selected broadband averages of the residuals are shown in each panel.PostScript for Figure 5 (Part 1)(1.08MB)
PostScript for Figure 5 (Part 2)(368KB)
Figure 6:
Residuals in 5Å Bins for the Individual Cycle 4 Observations of WD's, where Time of Observation Increases from Top to Bottom. Because of Geocoronal L-alpha contamination, the region around 1216A is not shown. The broad systematic deviations of 2-3% from unity are the intrinsic limits to FOS photometric precision. However, the first two observations of G191B2B on both the blue (a) and the red side (b) demonstrate a much better repeatability that is often seen for FOS over short intervals of a few days.PostScript for Figure 6 (544KB)
Figure 7:
The Changes to the Original 1994 March 21 Cycle 4 Pipeline Calibration for the 4.3" A-1 Aperture. The changes represent the ratio of the original pipeline flux in the .c1 files to a reprocessed .c1 file with the calibrations described here, except that averages over time are used for the variable red H19 and L15 sensitivities.PostScript for Figure 7 (355KB)
Instrument Science Report CAL/FOS-144