+--------------------------------------------------------+ | STScI Analysis Newsletter (STAN) | Cosmic Origins Spectrograph (COS) | Space Telescope Imaging Spectrograph (STIS) | June 2012 +--------------------------------------------------------+ In this Newsletter we provide some updates of interest to COS and STIS users who will be drafting and submitting Phase 2 HST programs over the next several weeks. -------------------------------------------------------------- Using multiple FP-POS positions at new COS Lifetime Location. In Cycle 20, the use of multiple FP-POS positions for any given Cenwave is recommended for all COS spectroscopic observations, especially in the FUV. -------------------------------------------------------------- New ETC Release (20.2): New dark current rates, throughput and sensitivity curves In preparation for Cycle 20 Phase II proposal submission, a new version of the ETC (20.2) has been released. As part of this new ETC release, the COS/STIS instrument team has updated some of the included instrument data. These updates include revised throughput and sensitivity values, as well as dark rates for each detector, based on calibration measurements made during the previous year. -------------------------------------------------------------- Summary of the new COS Lifetime Position Characteristics To overcome the effects of gain sag, the position of spectra on the COS FUV detector will be moved to a new lifetime position in late July 2012. This new lifetime position is displaced in the cross-dispersion direction by 3.5", corresponding to ~41 pixels. This change, affecting both COS FUV science and COS FUV target acquisitions, will be transparent to users preparing their Phase II with APT. No changes will be made to the location of the COS NUV spectra. -------------------------------------------------------------- A Reminder about CCD Charge Transfer Efficiency Changes The STIS CCD is a 1024 X 1024 pixel, thinned, backside illuminated SITe CCD, with sensitivity from below 2000 Å up to about 11000 Å. In a space environment, CCD detectors accumulate radiation damage, which over time leads to increasing dark current, more hot pixels, and reduced charge transfer efficiency. After fifteen years on orbit, the effects of such radiation damage on the STIS CCD have become substantial. +----------------------------------------------------------+ | Need help? http://www.stsci.edu/hst/stis/faqs/help +----------------------------------------------------------+ | To subscribe or unsubscribe to the STAN, send a message | to majordomo@stsci.edu with a blank subject line and | the following in the body: [un]subscribe cos_news | or [un]subscribe stis_news +----------------------------------------------------------+ | The Space Telescope Science Institute is operated by the | Association of Universities for Research in Astronomy, | Inc., under NASA contract NAS5-26555. +----------------------------------------------------------+
