|STIS Instrument Handbook for Cycle 25|
Set of three supported neutral-density filtered slits for use with first-order or echelle observations. The approximate dex ND factors are 0.4, 0.8, and 1.2, for 31X0.05NDA, 31X0.05NDB, and 31X0.05NDC, respectively. Their use for PRISM observations is ‘‘available-but-unsupported’’ this time.Observations with this slit require a PEAKUP prior to science observations. Use of these long slits with an echelle grating will cause order overlap problems (see Section 12.2), but for point sources the order separation may be adequate for many science programs.
Table 13.31: 31X0.05ND(A-C) Throughputs (%)