0.2X0.2 Aperture

Description

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 programs that do not have a scientific need for a long-slit (see
Section 2.8 STIS Snapshot Policies).

Table 13.25: 0.2X0.2 Throughputs

	% Throughput
1200	54.5
1800	67.2
2400	73.7
3000	77.2
3600	79.6
6000	81.7

Aperture	Projected Length (arcsec) (MAMA E-modes)	Width (arcsec)
0.2X0.2	0.2	0.2

Figure 13.72: 0.2X0.2 Aperture Throughput as a Function of Wavelength