|STIS Instrument Handbook for Cycle 25|
The F25QTZ filter with the FUV-MAMA provides high-throughput broad-band FUV imaging with better rejection of geocoronal emission than the F25MAMA or F25SRF2 modes and the same field of view and spatial resolution.With this filter the background is dominated by detector dark current. The dark current is not constant across the detector and not constant in time. This could limit the sensitivity for very extended faint targets, however, note that the FUV-MAMA dark is extremely low.Users may also want to consider whether the ACS SBC detector might be better for their observing program.
Pivot λ (Å) Speak Bλ R80 (arcsec) Figure 14.78: F25QTZ FUV-MAMA Integrated System Throughput and RedleakTable 14.32: F25QTZ FUV-MAMA Sensitivity & Throughput
Figure 14.79: Point source S/N vs. V+ABν for the F25QTZ FUV-MAMA mode. Curves are labeled by required exposure time (seconds).Figure 14.80: Extended source S/N vs. V+ABν for the F25QTZ FUV-MAMA mode. Top curves are for an area of 0.2 arcsec2; bottom curves are for 1 arcsec2. Average sky assumed. Curves are labeled by required exposure time (seconds).Table 14.33: Radial Profile for F25QTZ*
Figure 14.81: Point Source Encircled Energy for F25QTZ FUV-MAMAFigure 14.82: Point Source Intensity vs. Radius for F25QTZ FUV-MAMA