NICMOS STScI Analysis Newsletter 14
September 1998
CONTENTS:
- NICMOS NEWS
+ New NICMOS Information on the WWW
+ NICMOS Update
- RECENT PREPRINTS
- APPENDIX: NICMOS CONTACTS
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New NICMOS Information on the WWW
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by Doris Daou
Similar to all Space Telescope Instruments, the NICMOS home page on
the World Wide Web is updated with all instrument developments. The
NICMOS home page can be found by visiting the STScI WWW page
(http://www.stsci.edu/) and following Observing links to the NICMOS
Web pages.
Since last month, the following items have been newly posted:
* NICMOS Photometry Update, Last Updated: 2 September 1998
* NICMOS Parallel Program, Last Updated: 1 September 1998
* NICMOS Calibration Resources, Last Updated: 6 August 1998
* NICMOS Focus Update, Last Update: 17 September 98
* NICMOS PlateScale Update, Last Update: 25 August 98
* NICMOS Coronographic Hole Update, Last Update: 25 August 98
* NICMOS Unit Conversion Tool has been updated.
Since last month, the following Advisories have been posted:
* The NICMOS "Pedestal" Effect.
* NICMOS Camera 2 ACQ exposure times.
* Rate for NICMOS time conversion in error.
Since last month, the following ISRs have been published:
* Review of NICMOS Performance
* NICMOS Focus and HST Breathing
* NICMOS Focus Data Reduction and Analysis Using Phase Retrieval
NICMOS Update
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NICMOS operations have continued at a steady and high rate with the
expected completion of nearly the entire NICMOS science program
by November 15, 1998. A very small number of programs with
tightly constrained windows will be done after November 15 as long as
cryogen remains. In addition, a stepped up program of routine
monitoring will be conducted as described in detail below. The
predicted date of exhaustion of cryogen is near the end of December
1998 with about a 30 day uncertainty. Internal temperatures and
cryogen outflow rates continue to follow predicted curves. The
focus in all three NICMOS cameras has remained stable despite some
small fluctuations in the best derived NIC3 focus.
Planning for the end of NICMOS operations is nearly completed. The
overall goal of the end of life planning is to obtain data that will
help characterize NICMOS in the temperature range likely
to be achieved by the NICMOS Cryocooler and to leave the instrument
in the safest possible configuration while warm. Starting on 15
October 1998 a dark current monitoring program will run several times
per day during occultations when no other observations are possible.
This will provide a source of data in the unlikely event that the
cryogen runs out before 15 November. Temperature data from thermal
sensors will be monitored at an increased frequency to look for signs
of cryogen exhaustion although models predict that a detectable
change in temperature may occur only days in advance.
Starting on 15 November, after the completion of most of the
NICMOS science program, an increased calibration program will go
into place. Dark currents will be measured 12 - 14 times per day.
Flat fields will be taken 4 times per day and focus sweeps will be
obtained twice per week. In addition, NIC3 generic parallel
observations will be taken whenever possible. This heightened
monitoring will continue through cryogen exhaustion. Once the
onboard temperature sensors are no longer within their calibrated
range (i.e. at temperatures of about 80K or higher), observations
with NICMOS will be discontinued. The NICMOS filter wheel will be
stowed in the BLANK position as a hedge against additional
contamination of the filters. The Pupil Alignment Mechanism (PAM)
Mirror will be moved to the NIC1/2 compromise focus. No harm to
either the filter wheel mechanism or the PAM is expected during warm
up and subsequent cool down. NICMOS will remain in this
configuration until the Cryocooler is installed during the
next servicing mission, now expected in the spring of year 2000.
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RECENT PREPRINTS
----------------
We draw your attention to these papers, based on NICMOS 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.
KRIST, J.E.; GOLIMOWSKI, D.A.; SCHROEDER, D.J.; HENRY T.J.
"Characterization and Subtraction of Well-Exposed
HST/NICMOS Camera 2 Point Spread Functions for a Survey of
Very-Low-Mass Companions to Nearby Stars" PASP 9-98
www.stsci.edu/science/preprints/prep1263/prep1263.html
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APPENDIX: NICMOS Contacts
-------------------------
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. If you do not know who these
persons are, you can find the information on the WWW at
http://www.stsci.edu/public/propinfo.html.
Analysis, STSDAS or any other HST-related questions can also be
addressed to help@stsci.edu.
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