|STIS Instrument Handbook for Cycle 26|
The 25MAMA mode with the FUV-MAMA detector provides high-throughput broad-band far-ultraviolet (FUV) imaging with the highest available throughput at ~1500 Å and the highest possible spatial resolution.For long exposures of faint targets, sky background is likely to be a limiting factor. Observers should consider the use of DARKTIME or (preferably) use the F25QTZ filter, which has nearly the same throughput but rejects geocoronal Lyman-α and [O I] 1302 + 1306 Å air glow.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 14.66: 25MAMA FUV-MAMA Integrated System Throughput and RedleakTable 14.26: 25MAMA FUV-MAMA Sensitivity & Throughput
Figure 14.67: Point Source S/N vs. V+ABν for the 25MAMA FUV-MAMA mode. Curves are labeled by required exposure time (seconds).Figure 14.68: Extended Source S/N vs. V+ABν for the 25MAMA 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 14.27: Radial Profile for 25MAMA*
Figure 14.69: Point Source Encircled Energy for 25MAMA FUV-MAMAFigure 14.70: Point Source Intensity vs. Radius for 25MAMA FUV-MAMA