2.9 STIS Snapshot Program Policies

STIS MAMA imaging modes and the STIS NUV-MAMA PRISM will not be allowed in snapshot programs. Other spectroscopic STIS MAMA snapshots are allowed, but the combined total of STIS MAMA and COS snapshot targets accepted will be restricted. See the Cycle 33 Call for Proposals for further details. The prohibition on MAMA imaging and PRISM snapshot targets was instituted because the labor-intensive field bright-object checking requirements, when combined with the low-execution probability for STIS MAMA snapshots, results in a very inefficient use of resources. Likewise, moving targets are not permitted for STIS MAMA snapshot visits. Variable STIS MAMA snapshot targets must have well-defined maximum UV fluxes, which will be used for the bright-object checking. There are no restrictions on the numbers or variability of proposed STIS CCD snapshot targets, as they do not require bright-object checking and have a significantly higher expected completion rate. Thus, use of the STIS CCD G230LB or G230MB gratings is encouraged as an alternative to the NUV-MAMA for snapshot programs.

In addition, STIS MAMA snapshot proposals should be limited to one or a few straightforward configurations. Specifically, use of the F25NDQ filters will not be allowed in MAMA snapshot proposals. Use of the 0.2X0.2 echelle aperture is recommended (and now supported) for first-order programs that have no scientific need for a long slit, in order to expedite the field bright-object screening process. Because of the limited resources available for bright-object checking, combined with the relatively low expected completion rate, excessively complex STIS MAMA snapshot targets, fields, or instrumental configurations may not be implemented in Phase II. If in doubt on this issue, please consult with a member of the STIS Team via the Help Desk.