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| GGGGGGG HH HH RRRRR SSS |
STScI | GG HH HH RR R SS | STAN - GHRS
Analysis | GG GGG HHHHHH RRRRR SS | Number 21
News | GG GG HH HH RR R SS | September 1997
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CONTENTS:
- GHRS NEWS
+ Close-Out Calibrations
+ 1997 Calibration Workshop
+ The 1997 Data Handbook
+ GHRS Group Closure
- RECENT PREPRINTS
- APPENDIX : GHRS CONTACTS
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Close-Out Calibrations
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We have completed the following Instrument Science Reports, for which
these abstracts are provided:
ISR083: "The Far Wings of the GHRS PSF"
The GHRS Point Spread Function (PSF) was measured directly by stepping
(dwell scan) the Small Science Aperture across the star HD 106343
(program ID: 6210) using the G160M and G270M gratings. Two scan
directions were sampled, along the instrument -x axis at wavelengths
1400 and 2700 A, and along the +y axis at 2700 A. The scan steps were
spaced 0.4 arcsec apart and went out to a radius of 3.0 arcsec from
the star. RAPID mode (sample time of 1 second) was used to measure the
counts at each dwell position. Nine points were extracted from the
data to define the PSF envelope. The PSF exhibits a low-intensity side
lobe peaking at a radial distance of ~2.0 arcsec.
ISR086: "GHRS Cycle 5 Calibration Close-Out"
This document summarizes the Cycle 5 calibration program for the GHRS,
both as planned and executed.
ISR087: "GHRS Cycle 6 Calibration Close-Out"
This document summarizes the Cycle 6 calibration program for the GHRS,
both as planned and executed.
ISR088: "Redetermination of Sensitivity for Echelle-A and G140M"
This ISR describes a redetermination of the GHRS sensitivity functions
for the Echelle-A and G140M gratings. Changes amount to ~20% for
Echelle-A over the entire range of wavelengths, compared to the previous
values. G140M also deviates slightly from the reference spectrum and
requires a linear correction with wavelength, amounting to ~2% at
1100 A and 8% at 1600 A. The procedures used to derive the corrected
sensitivity functions are described here, and new files have been
installed in CDBS.
ISR089: "Summary of the Post-COSTAR Side 2 Sensitivity Monitors for GHRS"
The sensitivity of the GHRS on Side 1 and Side 2 has been measured
approximately every 3 months since Cycle 4. The measurements were done
with the ultraviolet flux standard BD+28 4211. Significant time dependence
was detected in the Side 1 data, and led to a recalibration of the G140L
sensitivity, as discussed in GHRS-ISR085. Trends are also detected in
the Side 2 sensitivity monitors, although they are much less than those
found for G140L.
ISR090: "Redetermination of Sensitivity for Echelle-B"
This ISR describes a complete redetermination of the GHRS sensitivity
for the Echelle-B grating. The procedures used to derive the corrected
sensitivity functions are described here, and new files have been
installed in CDBS.
ISR091: "Summary of GHRS Documentation at STScI and a GHRS Bibliography"
This ISR lists all the documentation about the GHRS that is known to
exist at STScI, together with its disposition. The most important of
these are available to users on-line. Copies of paper-only documents
have been provided to the STScI library for archival purposes.
These have been posted on our web page.
1997 Calibration Workshop
-------------------------
An oral presentation was made to the just-concluded 1997 Calibration
Workshop that summarized the state of GHRS calibrations. A written
version has been submitted for publication in the conference proceedings.
A poster presentation was also made on recent calibration changes.
The 1997 Data Handbook
----------------------
All of the above (ISRs and workshop proceedings) has been incorporated
into the new Data Handbook, which we urge you to examine. The handbook
should be issued in November.
GHRS Group Closure
------------------
As of September 30, 1997, the GHRS Group at STScI no longer exists.
D. Soderblom has assumed responsibilities in Presto, L. Sherbert has
gone to SESD, and J. Mack is resuming her previous DA duties. Any
GHRS-related questions should be sent to help@stsci.edu.
We again thank the many people at STScI and everywhere who have made the
GHRS possible and who helped us provide service to you, the user.
D. Soderblom, L. Sherbert, J. Mack
September 30, 1997
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RECENT PREPRINTS
----------------
We draw your attention to these papers, based on GHRS data, that will appear in
the next few months. This list includes all preprints received by the STScI
Library not yet published in the journals. Please remember to include our
Library in your preprint distribution list.
MEYER, D.M.; JURA, M.; CARDELLI, J.A. "The definitive
abundance of interstellar oxygen" ApJ accepted
WOOD, B.E.; LINSKY, J.L. "The local ISM and its
interaction with the winds of nearby late-type stars" ApJ
accepted
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APPENDIX: GHRS contacts
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Any questions about the scheduling of your observations should be addressed to
your Program Coordinator. Post-Observation questions can be addressed to your
Contact Scientist.
Analysis, STSDAS or any other questions can also be addressed to help@stsci.edu.
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The Space Telescope Science Institute is operated by the Association of
Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.
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