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Space Telescope Imaging Spectrograph
STAN - April 1997

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             |        SSS  TTTTTTT  IIIIIII    SSS        |
STScI        |       SS       T        I      SS          | STAN - STIS
Analysis     |        SS      T        I       SS         | Number 2
News         |         SS     T        I        SS        | April 1997
             |       SSS      T     IIIIIII   SSS         |
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CONTENTS:

       - STIS NEWS 
         + Reminder on Keeping up to date with STIS
         + STIS MAMA Phase II Deadlines - Submitting STIS Phase IIs
         + STIS MAMA Update Released
         + RPS2 7.1 Released
         + New Spectroscopic ETC Released
         + STIS Observers with Approved NICMOS Parallels
         + Revised MAMA Bright Object Protection Limits Required
         + CCD Filter Red Leaks and Exposure Time Calculator Updates
         + SMOV Progress and Cycle 7 Calibration Planning

       - NEW STIS DOCUMENTATION 
         + STIS ISRs (Instrument Science Reports)...
         + STIS FAQs (Frequently Asked Questions)...
         + STIS Advisories...
         + STIS Related RPS2 Advisories...
         + Other (Updates, Technical Memos, etc.)...

       - APPENDIX: STIS CONTACTS

============================================================================

Reminder on Keeping up to date with STIS
----------------------------------------

This is the second in the series of monthly STAN STIS reports. As
always, you may obtain the latest news and important announcements, as
well as review related STIS documents on the instrument, proposal
preparation, frequently asked questions and contacts by visiting the
STScI WWW page (http://www.stsci.edu/) and following Observing links to
the STIS web pages.

Information contained in the various links to this page will be updated
on a continuing basis.

If you have questions or comments about the contents of the STAN, our
WWW pages or information posted there, general STIS questions not
directly associated with your Phase II submission, or requests for
documentation, please email help@stsci.edu and we will answer you
promptly.


STIS MAMA Phase II Deadlines - Submitting Your Phase II proposals
-----------------------------------------------------------------

The STIS MAMA Phase II deadlines are approaching.  In an effort to help
alleviate the workload caused by a large influx of proposals, GOs have
been assigned deadlines of May 9, May 16 or May 23.  The MAMA Phase II
update, the RPS2 7.1 software and an enhanced STIS Spectroscopic
Exposure Time Calculator were recently released in support of the Phase
II preparation (see below).  Should you have any questions needing a
timely response while preparing your program, please contact your
Program Coordinator or Contact Scientist.  We remind you that it is
important that you get your clean Phase II submissions in on or before
the deadline given to you.  If you are going to have problems meeting your
deadline, please let your PC and CS know so we can keep up with our
proposals, and still help you.

We recommend that GOs not "over-engineer" their proposals to get the
last second of visibility out of every exposure as RPS2 provides only
model visibilities and as the underlying TRANS software and our
understanding of the recommended best procedures for obtaining science
is likely to evolve slightly as we learn more about the instruments
through SMOV.  We remind you that you will have a planned `science
rework period' for your proposals roughly 10 weeks before the execution
of your first visit (we will be contacting you once your proposal is on
the Long Range Plan to set up that targeted science rework period).
This will allow you to make detailed science changes to your proposal
to optimize the science based on the latest information available. We
also remind you that target or ORIENT or scheduling constraint changes
will not be accepted at that time and must be finalized with your
initial submission.


STIS MAMA Phase II Update Released
----------------------------------

The update on STIS MAMA performance for Cycle 7 Phase II preparation
was distributed 7 April 1997.  The update provides important
information on a number of topics including

   - Sensitivity and Throughput
   - New Operating Procedures and Their Impact to GOs
   - MAMA Acq/Peaks
   - MAMA Subarrays
   - Reduced Wavelength Coverages of Echelle Formats
   - Bright Object Screening of MAMA Imaging Fields
   - The STIS Imaging and Spectroscopic Exposure Time Calculators
   - Miscellaneous Corrections to the STIS Instrument Handbook

Postscript and PDF versions of the updated document may be retrieved
from the STIS web site under the Proposal Resources link.  Hard copies
have also been mailed to all observers with approved Cycle 7 STIS
programs.


RPS2 7.1 Released
-----------------

The latest version of RPS2 software was released 17 April.  This
version provides support for MAMA capabilities and includes bug fixes
since the last release of RPS2.  MAMA related information may be found
in the MAMA Phase II update noted above and the latest CCD information
is found in the CCD Phase II update issued in February 1997 and the
information contained in STANs #1 and 2.  Additional RPS2 information
may be found on the Proposal Resources link of the STIS web page.  All
Phase II proposals to be submitted on one of the specified May
deadlines should be run on the newly released version of RPS2.  To
download RPS2 7.1, go to the STScI Observer Page and select the "Phase
II Program Development (RPS2) and Checklist" link.  The newly released
RPS2 files are located in the "RPS2 Software" link.


New Spectroscopic Exposure Time Calculator Released
---------------------------------------------------
 
The new STIS Spectroscopic Exposure Time Calculator (ETC) is now
available on the WWW (see the STIS Proposal Resources page).

The new ETC has a larger set of input model spectra, which include 25
Kurucz models, power law, black body, a set of HST-standards, a few
non-stellar model spectra, and more.  The qso-spectrum can now be
redshifted to any desired value.  An additional LMC extinction law is
also available.  The ETC now has the facility for all the supported
Binnings, Gains and CR-SPLITs.  The new ETC takes the updated dark
current, read noise and throughputs as given in the Phase II update.
The user input spectrum can now be normalized to a given flux at a
certain wavelength, or can be submitted `as is'.

The new ETC provides an ID number at the top of the output page.  All
output pages for a given calculation (count rate analysis, plots, etc)
have the same ID number at the top which should help the user in cross
reference.  Users who encounter difficulty with the ETC should inform
us of the ID number which will help us in tracking the problem more
easily.

For more details on the ETC there are on-line help files which can be
obtained by clicking on appropriate highlighted words in the exposure
form.


STIS Observers with Approved NICMOS Parallels
----------------------------------------------

STIS observers with approved NICMOS parallels should be aware of the
new NICMOS developments which impact strategies for obtaining parallel
observations with NICMOS. There is a special section on parallel
observing in the Update on NICMOS Performance. This update will be
distributed to all NICMOS observers and placed on the NICMOS Instrument
WWW page; we refer you to that document for the relevant technical
information. We also bring your attention to the FAQ (see below) on
coordinated Parallels which describes a useful strategy to employ when
adding TAC approved coordinated parallels to your STIS proposal. STIS
observers with attached parallels are expected to submit their Phase II
proposals on their assigned deadlines.


Revised MAMA Bright Object Protection Limits Required
-----------------------------------------------------

As noted in the MAMA Phase II Update, the NUV-MAMA and FUV-MAMA imaging
filters were recently scanned to measure the out-of-band response to
look for evidence of red leaks.  The filters which were found to have
significant red leaks are: CN270, MgII and CIII] filters.  The CN270
and MgII filters have red leak longward of 400 nanometers, the details
of which can be found in the MAMA Phase II Update.  The CIII] filter
has a significant red leak between 200 and 450 nanometers.  The [OII],
CN182, Ly alpha, Quartz and the SrF2 filters do not show any sign of
red leak. The red leak becomes substantial for A0 and later stars.  New
filter specifications (including end-to-end transmission curves) are
posted on the web under the Calibration button on the STIS Instrument
page for all the CCD and MAMA imaging modes and have been incorporated
into the ETC (see below).  These out-of-bound filter throughputs are
based on scanning of the flight spares; on-orbit measurements of the
flight filters will be obtained as part of the Cycle 7 calibration
program, later this year.

Bright Object Protection screening limits are significantly impacted
for objects with continua rising rapidly towards the red.  New MAMA
imaging mode Bright Object Protection screen tables will be posted on
the STIS web page soon.  Observers with MAMA imaging programs may wish
to contact their CS for the latest information.


CCD Filter Red Leaks and Exposure Time Calculator Updates
---------------------------------------------------------

We noted in STAN #1 that the STIS [OIII] filter F25X50OIII was found to
have a red leak centered at roughly 1110 nanometers with a width of
approximately 60 nanometers, and a filter transmission of about 80% at
the peak.  As noted above, the CN270, MgII and CIII] filters have also
been found to have substantive red leaks.   The new filter throughputs
for both CCD and MAMA Imaging modes were incorporated into the STIS
Exposure Time Calculator (ETC) on 11 April 1997.  If you calculated
exposure times, saturation limits, or expected counts using the imaging
ETC for one of the above mentioned imaging modes prior to this date,
you may wish to re-perform your calculation.


SMOV Progress and Cycle 7 Calibration Planning
----------------------------------------------

STIS SMOV has been proceeding at a good clip and the results continue
to be very promising.  The major highlight of the last month for STIS
has been testing of target acquisition using the CCD. The results
demonstrate the proper performance of the acquisition and peakup
software, with accuracies at the level advertised in the handbook or
better being obtained for very bright sources.  The tests have also
shaken out several flight software modifications that will need to be
put in place to optimize performance of the acquisitions and peakups
for fainter sources more typical of science targets, and work is
proceeding to implement these changes over the next few months in time
for Cycle 7 science.

Work has continued apace to complete the flight software modifications
needed to protect the MAMA detectors from spurious resets caused by
cosmic ray upsets of the opto-isolators in the MAMA control
electronics.  Final testing of the newly developed software is expected
to be complete by mid April, with the first turn on of the MAMA
detectors following on in early May. The checkout of the performance of
the MAMA detectors through SMOV is expected to follow on shortly
thereafter, with information on their performance expected to become
available in early June.

More information on the STIS SMOV program can be found on the STIS web
page under the Calibration button, where you can access the weekly HST
Updates.

Work has begun in earnest within the STIS Instrument Group at STScI to
develop the Calibration Plan for Cycle 7.  Over the course of the next
few weeks our planning will begin to solidify.  At that time we will
post under the Calibration button of our STIS Instrument Page on the
WWW, a draft calibration plan and we will solicit comments from you on
its content.  So expect to be hearing from us again soon!


============================================================================

                           NEW STIS DOCUMENTATION
                           ----------------------

All new STIS related documentation noted here, along with previous
items, may be found on the "Documentation" link off the STIS Home
Page.


STIS ISRs (Instrument Science Reports)...
-----------------------------------------

During the past month 2 new ISRs were released and one updated.
These include

97-06   Mode Selection Mechanism Repeatability
97-05   The STScI STIS Pipeline IV:  Combining REPEATOBS Data (Rev. A)
97-03A  A User's Guide to Target Acquisition With STIS (Revision A)
        updated ACQ/PEAK accuracy
        updated table of limiting exposure times
        updated plots of exposure time to achieve a S/N of 40


STIS FAQs (Frequently Asked Questions)...
-----------------------------------------

POS TARG and PATTERN
coordinate system def:  What is the definition of the coordinate 
                        system used for the POS TARG and PATTERN 
                        commands?  Specifically, is it the aperture 
                        that moves on the sky, or does the target 
                        move relative to the aperture?
Coordinated Parallels:  What is a good strategy for adding my TAC
                        approved coordinated parallels to my 
                        proposal?
Aperture Orientations:  What are the orientations of the F28X50LP,
			   F28X50OIII, and F28X50OII?
CCD sub-array readout:  For the CCD, which readout direction is
                        truncated for sub-arrays?


STIS Advisories...
------------------

No new advisories have been posted to date, but the user should
regularly check the advisory page off the STIS Home Page during
proposal preparation for new items.


STIS Related RPS2 Advisories...
-------------------------------

RPS2 7.1 was released 17 April 1997.  Software related to advisories
posted for prior versions of RPS2 have been resolved and fixed in the
current release.  Three advisories have been posted related to RPS2
7.1.  It would also be wise to frequently check the RPS2 Advisory link
off the STIS Proposal Resources web page for up to date information on
any new problems identified with the current software release.

   - STIS/CCD ACCUM exposure has odd "0th" piece
   - Field of View (FOV) PostScript files are blank
   - System error: Feasibility analysis unexpectedly failed
     (related to inappropriate use of STIS MAMA ACQ/PEAKs)


Other (Updates, Technical Memos, etc.)...
-----------------------------------------

MAMA Phase II Update:  See the section in this STAN above relating to
the MAMA capabilities and procedures for handling acq/peaks, subarrays,
etc.

============================================================================

                          APPENDIX: STIS 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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