|Space Telescope Science Institute|
|STIS Instrument Handbook|
The 25MAMA mode with the NUV-MAMA provides high-throughput broad-band near-ultraviolet (NUV) imaging with excellent pixel sampling and very high throughput at ~2500 Å. The field of view is 25x25 arcsec.NUV-MAMA clear images will be somewhat out of focus because the mirror optimally focuses for use of a filter. Whenever possible, use F25SRF2 or F25QTZ instead of 25MAMA for NUV-MAMA imaging.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 should also consider whether the ACS HRC with the F220W or the F250W filter might be a better choice for their science goals.
Pivot λ (Å) Speak Bλ R80 (arcsec) Figure 14.23: 25MAMA NUV-MAMA Integrated System Throughput and RedleakTable 14.10: 25MAMA NUV-MAMA Sensitivity & Throughput
Figure 14.24: Point Source S/N vs. V+ABν for the 25MAMA NUV-MAMA mode. Top curves are for DARKTIME. Bottom curves are for average sky. Top curves are for DARKTIME. Bottom curves are for average sky. Curves are labeled by required exposure time (seconds).Figure 14.25: Extended Source S/N vs. V+ABν for the 25MAMA NUV-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 14.11: Radial Profile for 25MAMA*
Figure 14.26: Point Source Encircled Energy for 25MAMA NUV-MAMAFigure 14.27: Point Source Intensity vs. Radius for 25MAMA NUV-MAMA