Hubble Space Telescope STIS Available-But-Unsupported Modes
Starting on Dec 16, 2014, the calibration of a number of available-but-unsupported STIS instrument configurations was disabled in On-The-Fly-Reprocessing (OTFR). These available-but-unsupported modes are available for use in observations with a scientific justification, however the calibrations for these modes will be neither provided nor supported by STScI. Prior to Dec 16, 2014, the rules governing which datasets are calibrated through OTFR did not specifically exclude these available-but-unsupported modes. As a result, CalSTIS was run and the calibrated products were ingested into the archive and available upon request. Due to the unsupported nature of these modes, the calibrations performed were not optimized or not applicable and thus the products are not scientifically reliable. Any requests for these datasets will now no longer deliver calibrated products. For more information on available-but-unsupported policies for STIS, see Section 2.4 of the STIS Instrument Handbook. For a list of all modes and whether they are supported or not, see Appendix A of the STIS Instrument Handbook.
STIS data taken prior to HST servicing mission 4 in May 2009 have been statically archived in MAST. This means that these datasets do not pass through OTFR, but are instead delivered with the calibrations and settings used upon initial population of the static archive in 2006. Datasets utilizing the available-but-unsupported modes that are contained in the static archive will continue to be delivered with the full suite of calibrated products upon request through MAST. These datasets suffer from the same unreliable calibrations as their OTFR counterparts, and should not be used for scientific analysis without extreme scrutiny.