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Report of CTIO Users' Committee (1Mar93)
(from CTIO, NOAO Newsletter No. 33, 1 March 1993)

The CTIO Users' Committee held its annual meeting in Tucson on 15 and
16 October 1992, and after discussions with CTIO Director Robert
Williams, submitted the following report:

"It is of vital importance for US astronomical research that the
scientific community have continued access to a first-class observatory
in the southern hemisphere. The committee strongly commends CTIO for
continuing to provide such a research facility and for maintaining its
traditional high priority towards observer support, especially in these
times of restricted budgets. The committee wishes to emphasize that any
major budget cut at this point will result in the reduction or
elimination of a vital component of CTIO operations.  CTIO is
particularly vulnerable in that the dollar-peso exchange rate continues
to be unfavorable. The committee appreciates the fact that the NSF has
so far made up for the major annual shortfalls created by the
dollar-peso exchange problem.

Gemini Project
The committee reiterates its strong support for the southern hemisphere
component of the Gemini project. The construction of an 8-m telescope
on Cerro Pachn represents the next crucial step forward if US astronomy
is to maintain state-of-the-art access to the southern hemisphere
skies. Discussions are now beginning that will define the role that
CTIO may play vis-a-vis the operation of the Gemini 8-m. Clearly, there
are major benefits in combining certain aspects of CTIO and Gemini
operations. On the other hand, there are concerns that Gemini not drain
CTIO resources, and, conversely, that the demands of CTIO operations in
a potentially tightening financial environment not compromise
operations of the 8-m. The committee recommends that the initial
efforts to clarify the CTIO/Gemini interrelations be continued.

Major Instrumentation Projects
Before commenting on three main instrumentation projects ongoing at
CTIO, the committee wishes to emphasize the important role played by
the relatively small, but productive ETS group in La Serena. The
committee strongly endorses maintaining a small but vigorous
instrumentation group in La Serena. It provides CTIO with flexibility
in selecting and implementing instrumentation projects (e.g., the 4-m
imaging improvements) and also serves as a major stimulus to both the
ETS and the scientific staffs. Furthermore, the fact that 60% of ETS
time is spent on preventive and other sorts of maintenance is a major
reason for the high level of user satisfaction with CTIO.

4-m Image Quality
Several projects are underway to improve the image quality at the 4-m;
these projects have been described in previous issues of the NOAO
Newsletter.  The committee fully endorses the efforts to improve both
the thermal environment (mostly completed) and the performance of the
optics (via refinishing of the secondary mirror and active control of
the primary mirror and the secondary mirror alignment). We note that
the projects are being carried out expeditiously, and encourage the
observatory to carefully document the results of these improvements.

Arcon
In last year's report it was noted that full scale testing of the Arcon
controller was imminent. The current status of the project is that a
full conversion to Arcon controllers will take place over the next two
years. We hope that this can be carried out as quickly as possible
given the time already devoted to the project and the increasing need
for these new controllers, particularly for use with the large format
CCDs.

IR Instrumentation
Because of the effort devoted to the 4-m seeing improvements and to the
Arcon controller project over the past few years, the IR
instrumentation effort has been delayed. In a 3-year instrumentation
plan presented by Mark Phillips, CTIO advocates a shift in emphasis to
IR instrumentation as the above two projects are completed over the
next two years. The committee endorses this plan, which includes
implementation of NICMOS chips, development of a new IR spectrograph,
and construction of new cameras. As an interim measure, CTIO has
entered into discussions with Ohio State University about making
available their OSIRIS instrument on both the 4-m and the 1.5-m
telescopes for most of the second semester of 1993, in exchange for
some observing time. OSIRIS consists of a general purpose near-IR (0.9
to 2.5 um) imager and medium resolution long-slit spectrometer (R=550
and 1500). The detector is a 256 x 256 HgCdTe array.  OSU astronomers
would be on hand for the beginning of each observing run.  The
committee endorses this potential arrangement between CTIO and OSU in
order to bridge the gap until the CTIO NICMOS-based instruments come on
line.

In the longer term, CTIO proposes to implement an f/15 IR secondary at
the 4-m, to keep it consistent with the KPNO 4-m. This upgrade would
allow CTIO to enter joint IR instrumentation efforts with the KPNO IR
group and to share major IR instruments with KPNO. The committee agrees
with this approach.  This is clearly an arrangement that would provide
significant budgetary and human resource efficiency to the benefit of
both observatories. Consequently, funding for the IR secondary should
be provided by NOAO, rather than exclusively from CTIO funds.

Finally, the committee recommends that in future meetings when large
instrumentation projects are discussed, time and cost lines should be
presented.  While it is recognized that time and budget lines are not
always easy to adhere to in complex development projects, it certainly
helps the committee to better understand the flow of a particular
project (especially new members on the committee) when such information
is presented.

Other Instrumentation Projects
CTIO has joined in an agreement with STScI to develop new spectrograph
cameras for the wide-format CCDs to be implemented on the 1.5-m and 1-m
Cassegrain spectrographs. CTIO will supply the optics, and STScI will
provide the mechanical components. The committee is highly supportive
of this type of external collaboration as a means of realizing
important, but lower-priority, projects that are of wide benefit to the
user community. We note that completion of this important upgrade to
spectroscopy on the smaller telescopes is dependent on the packaging
and testing of the 1K x 3K Loral chips. While we recognize the enormous
demands already being made on the chip thinning and packaging group in
Tucson, we urge that the 1K x 3K chips be given high priority, as their
implementation will greatly enhance the scientific productivity of all
the CTIO spectrographs.

Aside from the above concern about timely delivery of the 1K x 3K Loral
chips, the committee notes that there has been a considerable
improvement in the quantity and quality of the CCDs available to users
of CTIO.

Other Issues
TAC Procedures
Considerable discussion took place concerning the utility of external
referee reports to the CTIO TAC. This issue was discussed both at a
joint meeting of the KPNO and CTIO Users' Committees and by the CTIO
Users' Committee alone. Our principal conclusion and recommendation is
that the current form of the external referee process is of marginal
value and should be discontinued. The main difficulty with the present
system is that each reviewer typically receives only a few proposals,
and hence cannot provide useful relative rankings. Since most proposals
are good, the TAC tends to receive uniformly positive responses, which
is of little value in their attempt to produce relative rankings of
proposals. There is significant effort expended by CTIO staff in
choosing referees, mailing proposals to referees, and collecting
reports. After considering a modification to the external review
process whereby each reviewer would receive approximately 15-20
proposals, the committee finally agreed that the external review
process should be abandoned. We recommend that the CTIO TAC procedures
should be restructured more along the general lines of the KPNO TAC. An
important ingredient of this restructuring would be to have feedback on
failed proposals coming directly from the TAC, rather than from
comments by the external reviewers. Furthermore, the TAC should be
enlarged to insure that its members represent all major areas of
research.

NASA Satellite Link
Use of the NASA link to CTIO continues to rise, and it has become an
indispensable part of CTIO operations. In particular, it allows for
major cost reductions and time savings in terms of the number of
observers actually travelling to Chile. Faculty members can effectively
advise their graduate students without going to Chile, and
collaborators on complex observing projects can provide substantial
assistance over the link, thereby decreasing the number of observers
required at CTIO. The committee urges that the link be maintained and
upgraded.

Data Archiving
A discussion of data archiving was held at the joint meeting of the
CTIO and KPNO Users' Committees, and is summarized in the KPNO Users'
Committee report from last year (see NOAO Newsletter No. 29). Our
committee is glad to see that efforts are being made to implement a
data archiving program at KPNO. As mentioned in last year's report,
CTIO should continue to monitor the progress of this important effort
and adopt the archiving methods developed at KPNO.

Night Assistant on the 0.9-m
The night assistant currently shared between the 0.9-m, the 1-m, and
the Curtis Schmidt is being upgraded to a mountain IRAF support person.
Until now, the night assistant generally resided at the 0.9-m for most
or all of the night. Under the new scheme, the IRAF support person will
be available as a night assistant on the 0.9-m for the first half night
of each new observer's run, and otherwise will be primarily intended
for IRAF support at all telescopes. The committee recommends that this
new arrangement be monitored to insure that the 0.9-m observers are
adequately supported.

Other Topics of Discussion
Other issues were discussed that did not lead to specific
recommendations on the part of the committee. CTIO Director Bob
Williams discussed the funding situation at CTIO, including the
dollar-peso exchange problem cited above.  Approximately 50% of the
CTIO budget is spent in pesos, primarily in salaries.  Scientific
staffing has maintained a constant level for the past 10 years; the
recent increase to three postdocs has been a major plus for the
observatory.  There is a vacancy in the instrument scientist area, but
hiring is now frozen.

Williams also discussed statistics on 4-m down time. Down time is only
1/2 to 1/3 as much as at other large telescopes for which those
statistics are known. He also reported that approximately 150 Ph.D.
thesis projects were awarded time at CTIO telescopes during the past
three years, which is comparable to KPNO.

There was a lengthy discussion about travel support. At this point it
is not clear if lack of full travel support has affected observing
patterns. Observers appear to manage to get support from various
sources. Some emergency funds are available beyond the standard
in-Chile support for PI's, and graduate students continue to be
supported for thesis research. The committee recommends that an effort
be made to determine whether the current level of travel support is
affecting use of CTIO.

There was also considerable discussion about the Pachon site survey.
Mark Phillips reviewed the excellent characteristics of the Pachon site
that has been tested so far. These results have been reported
previously in the NOAO Newsletters. At the joint meeting with the KPNO
Users' Committee, Sidney Wolff explained that the Pachon site survey was
discontinued due to lack of funds in the Gemini project. The Gemini
project is convinced that (a) Pachon has been demonstrated to be at
least as good as Tololo and the other AURA peaks, and (b) that it is
unlikely for there to be significant variations in quality between the
various sites on Pachon since they populate a main ridge that is
oriented orthogonal to the prevailing wind direction. Further testing
would strain the Gemini budget and perhaps delay completion of the
project.

An update was given on "maintenance" projects, which include upgrading
of telescope control systems, 4-m slit-viewing optics, Argus IIa, etc.
Maintenance projects account for 60% of the time spent by the ETS
group, with the remaining 40% going to the instrumentation projects
described above. A great deal of emphasis is placed on maintenance of
existing equipment.

Some concern was expressed about the lack of manuals for some of the
instrumentation, e.g., Argus. The committee was told that there should
be significant improvement during the next year.

Finally, Jim Rose gave a brief report on the UNC-Columbia-CTIO SOAR
telescope project. An update on this project will be published in the
next issue of the NOAO Newsletter.

CTIO Users' Committee:
J. Rose (Chair), M. Bolte, J. Frogel, J. Graham,
K. Meech, J. Patterson, M. Rubio, M. Shara

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