|STIS Instrument Handbook for Cycle 25|
The “utility” slit for the echelle gratings. This slit is the most photometric of the supported echelle slits and has the highest throughput for photon statistics. Starting in Cycle 12, this slit is also supported for use with the first order gratings, and it is the recommended aperture for first order MAMA snapshot and survey programs that do not have a scientific need for a long-slit (see Section 2.9 “STIS Snapshot Program Policies”).
Table 13.25: 0.2X0.2 Throughputs
Figure 13.72: 0.2X0.2 Aperture Throughput as a Function of Wavelength