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Space Telescope Imaging Spectrograph
New STIS spectral extraction box size options in ETC

STIS Bright Object Protection Requirements for GOs in Phase II

Please note that GOs using the STIS/MAMA configurations are required to submit bright-object reviews of all their targets and fields, derived with the APT Bright Object Tool (BOT) and the STIS Exposure Time Calculator (ETC), by the Phase II deadline. The detailed responsibilities and procedures are spelled out in the STIS Instrument Handbook (IHB), Section 7.7.4.

As explained there, ETC calculations of global and local rates must be provided for all targets, and for all field objects reported as unsafe or unknown by the BOT, either showing that they are safe to observe, or documenting any unresolved issues with a plan to address the latter. These results may be included within the proposal text/comment sections, or in separate emails to the Contact Scientist, with copy to

The field size to be screened is highly dependent upon the different STIS apertures, with a minimum for the small echelle slits and maxima for direct imaging or slitless spectroscopy. POS TARGs, Patterns, or Mosaics increase the size of the field to be screened, while ORIENT restrictions reduce it. All of these configurations are automatically displayed by the BOT, which also calculates rates for all objects in the field with adequate GSC2 data. When the latter are not adequate, or result in an unsafe condition, further information is required to clear the object in question; if it cannot be cleared, it will not be observed. Further options are discussed in the referenced IHB section.

A minor error in that section is corrected here. In the seventh paragraph, an incorrect reference is made to tables intended to provide J- and F-magnitude bright limits for the STIS configurations, corresponding to unreddened O5 spectra, for use when only one of those magnitudes was provided by GSC2. The referenced tables in fact provide the V magnitude limits for various spectral types. Fortunately, the former information is no longer required, because the current APT/BOT release has been enhanced to automatically clear such cases as unreddened O5 stars, when applicable.