+-----------------------------------------------------+ | HST Spectroscopy STIS/GHRS/FOS | | STScI Analysis Newsletter Mar 2001 | | | +-----------------------------------------------------+ Errors in Processed TIME-TAG Data from STIS. +-STIS------------------------------------------------+ Errors in Processed TIME-TAG Data from STIS. We have identified errors in some processed TIME-TAG datasets. These errors will be corrected when raw TIME-TAG data are reprocessed by new ground software, scheduled for installation in the archive pipeline at the end of June. We will make another announcement when corrected datasets may be retrieved from the archive. STIS MAMA detector electronics occasionally report an erroneous time. Existing ground processing software fails to trap certain newly characterized errors in reported time. As a result, gaps or jumps in time may occur in processed TIME-TAG data. Also, existing ground software does not properly flux calibrate data from observations in which the actual exposure time differs from the EXPTIME keyword value (i.e. the requested exposure time). This can happen when STIS memory fills before it can be dumped, for example. None of these issues affect STIS MAMA data obtained in ACCUM mode. All investigators working with STIS TIME-TAG data should read the more detailed discussion of possible problems at the URL given above. This web page also serves as a distribution point for new software to ' detect errors in existing TIME-TAG event lists (_tag files), determine apparent exposure times from the event list, and correct fluxes in extracted spectra (_x1d and _x2d files). +-----------------------------------------------------+ | Need help? | | http://www.stsci.edu/cgi-bin/stis?cmd=help | +-----------------------------------------------------+ | To unsubscribe from this mailing list send email to | | majordomo@stsci.edu with the message: | | unsubscribe stis_news | +-----------------------------------------------------+ | The Space Telescope Science Institute is operated | | by the Association of Universities for Research in | | Astronomy, Inc., under NASA contract NAS5-26555. | +-----------------------------------------------------+
