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| HST Spectroscopy STIS/GHRS/FOS |
| STScI Analysis Newsletter July 1999 |
| |
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New HST Spectroscopy STAN Format & Content
We are continuing a transition to a new format for
the HST Spectroscopy STAN. At the top, an index of
topics is listed with the web address where you can go
to get all of the details. Below this, short summaries
are provided for each topic. And as always, the STAN
will be posted on the STIS web site, where all of these
topics will be hypertext links directing you to the
full writeup. All items appearing here and more are
posted on the STIS web site, but we will only highlight
items of particular interest or importance in the STAN.
CCD Bias and Dark Reference Files
Improved features in the New ETCs
Throughput Changes
G430M Focus Gradient Detected
STIS Cycle 9 Instrument Handbook
STIS Web Site Updates
+-STIS------------------------------------------------+
CCD Bias and Dark Reference Files
The procedure for the production of STIS CCD bias
reference files has recently been changed. This change
was prompted by the observation that hot columns in CCD
data are often not well eliminated in the pipeline
reduction. Recently, the hot column residuals have been
becoming more apparent due to the increasing number of
charge traps. Especially short exposures have been
suffering from residual hot columns.
Improved features in the New ETCs
The STIS Exposure Time Calculators have been
re-engineered, and they were made available on 4 August
1999 to help GOs prepare their Phase 1 proposals for
Cycle 9. These ETCs offer a number of new features,
which are described in the on-line help documentation.
Throughput Changes in Synphot
The synphot throughput files for all the gratings have
now been updated. The changes are most significant
(>7%) for the Echelle-modes, and for G230MB longward
of 2200A.
G430M Focus Gradient Detected
A time variation has been detected in the cross-
dispersion width of spectra which exhibit a strong
wavelength dependence. The strongly increasing width
with time, and with a strong dependence on dispersion
position is thought to arise from two factors: (1) over
this interval the telescope breathing was monotonic and
about a factor of two larger than typical values, and
(2) the G430M mode has an intrinsic focus gradient. The
G430M appears to have some power or astigmatism which
produces the observed focus gradient.
STIS Cycle 9 Instrument Handbook
The Cycle 9 STIS Instrument Handbook is now available
online in a variety of formats: One large PDF file,
smaller PDF files broken into chapters for faster
loading, and HTML.
STIS Web Site Updates
We are in the process of updating the STIS Web
Site in preparation for Cycle 9. There are
many changes, updates, and additions, and more on
the way. Most importantly for proposers, the
new Instrument Handbook, Phase I proposal
instructions, and the new ETCs are now available.
+-Spectrographs---------------------------------------+
List of Recent Preprints Now on Line
The list of preprints based on HST spectrographs data
that user to occupy this space is now available at
http://www.stsci.edu/science/preprints/ for easy browsing.
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