Report of the
Space Telescope Users Committee
November 1997
The Space Telescope
Users Committee met in open session on 24-25
November 1997, in the Board Room of the Space Telescope Science Institute.
Committee members in attendence were: W. van Breugel,
J. Clarke, R. Fosbury, L. Kay, P. McCarthy, R. Schulte-Ladbeck,
S. Terebey, R. Thompson,
F. Walter (Chair), and B. Woodgate.
Absent were J. Bally and M. Franx.
Minutes of the meeting are reported elsewhere.
This meeting featured no large crises, and hence our report has little
coherence, but is rather a shopping list of concerns. Some of these are new,
while others are carried over from previous meetings.
The role of the STUC is not to be critical, but rather to point out
concerns which affect the users of the HST, its archival database, and its
services. Although the meetings, and this report, tend to harp on what is
wrong, or what could be better, we realize the sheer
complexity of the HST and the efforts undertaken by the HST project and the
STSCI to keep everything functioning smoothly. We applaud everyone involved
in this project for all the hard work they have put in, from those in the
trenches, who are overworked and underappreciated, to those at the top who
must bear the brunt of the criticisms. It continues to be astonishing
how well such a complex operation as the HST functions.
STScI Manpower
The total investment in HST and its instrument suite is huge. The
scientific value of the hardware is directly dependent on the quality
and quantity of the instrument science effort which can be devoted to
understanding, calibrating and enabling the operation of the many modes
of these instruments. Given the complexity of operation of NICMOS and
STIS, the STUC is concerned that insufficient resources may be available
to fully exploit the capabilities of these instruments. It is understood
that the commissioning of all the capabilities cannot take place
immediately and it is appreciated that the quality of work and the
dedication of the instrument scientists and supporting personnel is very
high. It is apparent, however, that the number of highly skilled people
working on STIS and, particularly, NICMOS is so small that the
characterisation of the instruments is slower than
desirable. STUC urges the STScI to make a critical
appraisal of the balance of its resources devoted to instrument science
relative to other areas in order to address these concerns.
Southern Deep Field
The STUC concurs with the plans for the southern deep field, and anticipates
that it will prove as scientifically exciting as did the Hubble Deep Field.
Proposal review / TAC comments
The STUC appreciates the large effort by the STScI to conduct a cycle
7-delta review of proposals for NICMOS on a very short timescale.
The STUC acknowledges that the special circumstances may have required
a more austere review process to decrease the workload on the STScI
staff in dealing with proposal evaluation and response to users in a
timely manner.
The STUC is concerned, based on feedback from the user community to
STUC members, that the adopted philosophy for the cycle 7-delta review
process of
1) minimizing feedback to users on proposal evaluation by
using user "comment tables",
2) allowing TAC panels to provide only
advisory proposal rankings to the super-TAC, and
3) prohibiting TAC-panels
to adjust proposal requests when deemed appropriate,
is not in the best general interest of users.
The STUC therefore urges the STScI for future HST proposal cycles to
let users (TAC-panels) be in more control of the proposal evaluation,
and provide more useful feedback in the form of written comments
to users afterwards.
Advanced Camera for Surveys
The STUC recommends that the HST Project support the efforts of the ACS
Science Team to obtain an additional procurement of 2k x 4k CCDs, with
the goal of acquiring high quality CCDs for the Advanced Camera.
Because the ACS Science Team is presently exploring alternative ways to
acquire high performance CCDs, we think it is imprudent to specify in
detail how they should proceed. If the ACS team presents a convincing plan
that balances cost against schedule, performance, and risk, we recommend
that the project support the plan.
Scheduling
The STUC understands the difficulties faced by observers with deferred cycle 7
programs.
The STUC wholeheartedly supports the efforts of the STScI to
reduce the backlog of uncompleted cycle 5 and cycle 6 observations. We concur
with the scheduling prioritization currently implemented.
Planetary Working Group
Knox Long observed that the Planetary Working Group (PWG) was completing
work on the items that had earlier been raised by the STUC, and recommended
that the group now be disbanded. Indeed, progress has been made on all
fronts, and many tasks have been completed while in some areas the
work is planned to be completed within the next few months. We applaud the
personnel at STScI and on the instrument teams for their hard work and
responsiveness on these issues. The STUC agrees to disbanding the committee
subject to the competion of all action items, and we hope that this can
happen at the next STUC meeting in May 1998 following a presentation and
discussion among the committee members. At the same time, in the past there
have been recurring needs for such a group to address new issues, which
might again arise at some time in the future. The specific items not
yet completed are 1) distributing planetary target "finding charts" to
observers on a regular basis, 2) extension of track 51 segments to times
longer than 33 minutes so that consecutive observations during the same
visibility period can be related to each other in absolute pointing, and
3) any issues that arise from early observations with NICMOS and STIS.
One particular area to be watched will be the success rates of STIS and
NICMOS observations of moving and planetary targets, for which statistics are
now being accumulated. Specific questions for STIS and NICMOS observations
will be 1) reasons for any failed observations, 2) accuracy of pointing and
acquisitions, and 3) accuracy of post-observation pointing and ancillary
information. In particular, it remains to be seen how accurately the observer
can register the pointing with STIS spectra either by target acquisition or
following imaging. In the case of moving targets, the pointing with respect
to the center of a planet between consecutive exposures is often not
maintained, for example if the start times of linear track segments are
not exactly what was planned, so that an image does not necessarily show
where the aperture was pointed in a following spectrum. We hope that this
issue can be addressed and put to rest at the May STUC meeting.
Archival CP
The STUC notes that the length of cycle 7 is nearly 2 years. Because the
archival proposal process is tied to the observing cycle, users of the archive
will not have had a recent opportunity to propose for support for their
research. As grants are usually awarded on an annual basis, this has
caused financial hardships. The STUC urges that an archival proposal
opportunity be offered as soon as possible.
This special archival oportunity would follow the precedent set for the
NICMOS delta-CP. As the observing cycle returns to an
annual cycle, a single call for proposals would cover both archival and
observing opportunities.
We note with satisfaction that NASA and the STScI have agreed to a special
archival proposal opportunity to address this issue.
Support for New Users
STScI does a thorough job providing documentation and support for users.
However the system is very complex and time consuming to learn, and can
be overwhelming for new users. New users have special needs to get them
onboard quickly -- overviews, tips, and cookbook documentation. These
need not be time consuming tasks for Institute Staff to be worthwhile.
These recommendations mainly concern a particular type of new user: those
unaffiliated with institutions, or those at small institutions with limited
institutional support. Efficient use of the phase II proposal preparation tools
requires either a SUN workstation or access to a fast internet connection.
The kind of help which would prove would most useful includes:
- Pre-phase II travel support to the STScI to learn how to use RPS2 and
to generate the Phase II proposal. A user without a SUN workstation or a
quality internet connection is at a particular disadvantage, and there is
generally insufficient time between announcement of the Phase I results
and the Phase II
deadline to obtain funding to purchase and install appropriate hardware.
- Special assistance provided by STScI staff to new users.
This assistance would entail a greater greater level of
effort (per GO) than is possible for the program coordinators
or contact scientists.
- New users also benefit from training in how to use the data reduction
software. Please continue to encourage new user visits, and provide the
staff needed to support those visits.
Software Support
The STUC appreciates the difficult job that the software support personnel
have in attempting to keep STSDAS current, between the new instruments,
upgrades of IRAF, and the multitude of platforms observers wish to use.
Some of the recent difficulties in obtaining up-to-date versions of STSDAS
are due to inevitable delays in porting IRAF 2.11 from SUNs to other
platforms (over which the STScI has no control).
The STUC supports the decision to port the pipeline software to
OpenIRAF (coded in C).
The STUC admonishes the user community not to expect miracles.
STUC Membership
The STUC is comprised of 12 members, each of whom serves a 3 year term
beginning with the Spring meeting.
In principle, 4 new members are selected each year. The carryover of
8 members provides for a strong continuity to the committee.
Due to three resignations, there were 7 new members selected in 1996.
When these members rotate off in November 1998, there will be left only 5
members with experience.
The STUC recommends that the two members rotating off this year be replaced
with 4 members, and the 7 rotating off in 1998 be replaced with 5 members in
1999. The STUC will have 14 members for one year, and 7 returning members
for 1999.
The STUC recommends that, as policy, the PIs of newly installed instruments
be voting members of the STUC for a normal 3 year term beginning near the
time of instrumenmt installation. The PI of the ACS should join the STUC in
May 2000. This ensures a voice for the GTOs, as well as the GOs.
The STUC recommends that the PIs of all instruments selected for future
flight be non-voting members of the STUC, and be encouraged to attend the full
meetings.
The NICMOS Cryocooler
The committee remains less than enthusiastic about the proposed NICMOS
cryocooler.
As we stated in our May 1997 report, "Any decision to fly a cryogenic cooler
for NICMOS should be made only after
due considerations of all potential impacts on the spacecraft and the other
instruments, and on the financial resources of the project. Funding for
the cryogenic cooler must not be taken from UPN 459, and must not decrease
the funding available for the year 2002 instrument."
The committee is also concerned that, even if the cryocooler is proven a
viable concept, the scientific return from NICMOS in the era of
large ground-based IR-optimized telescopes, adaptive optics technology, and
improved detector technology may not be cost-effective. We recommend that
this matter be investigated further.
WF3
The STUC was informed that the HST project is considering building a spare
camera (WF3) from parts available from WFPC1 and utilizing spare ACS detectors.
The motivation is to provide backup imaging capability for the extended
HST mission through 2010.
The STUC is concerned about both how the decision to do this was arrived at,
and how the new instrument will be funded.
There are concerns that this
decision compromises the peer-review process. If the project sees a need to
construct a facility instrument, it should convene an open panel to recommend
an instrument design.
The STUC is concerned about the source of funding for this instrument. We
strongly recommend against use of UPN459 funds, especially if this reduces the
amount of funding available to the GOs.
This report submitted by
Frederick M. Walter
on behalf of the Space Telescope Users Committee
February 1998
fwalter@astro.sunysb.edu
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