Report of the 62nd meeting of SAC
Waimea, CFHT headquarters, November
15-16 2002
The meeting was attended
by SAC members Pierre Bastien, Jean-Luc Beuzit, David Bohlender (vice-chair),
Laurent Drissen, Eric Emsellem, Eduardo Martin , Marguerite Pierre, Chris
Pritchet, Geneviève Soucail (chair) and Brent Tully. Taiwanese representative
S.Y. Wang and Korean representative M.W. Chun were present as observers.
Greg Fahlman, Christian Veillet, Derrick Salmon and CFHT staff members
participated in the discussions.
On November 15, a summit
visit was made by P. Bastien, D. Bohlender, M.W. Chun, L. Drissen, E. Emsellem,
M. Pierre, G. Soucail, B. Tully, accompanied by G. Fahlman, D. Salmon,
and C. Veillet.
AGENDA
1.Technical
activities report
2
Instrumentation and Project Reports
1.
PUEO NUI: organization of a scientific workshop
2.OHANA:
progress report and science cases
3.Sky
Probe: status of the upgrade and upgrade plans, CFHT DIMM seeing monitor
4
WIRCam: progress report, report of the Steering Group, WIRCam surveys at
CFHT
5.ESPaDOnS:
project status, schedule and installation
6.
MegaPrime: project status and commissioning
3.Telescope
use and scheduling for 2003A. Trends in time application
4.Evolution
of the instrumental suite: MOS/OSIS and Gecko/Cafe
5.The
CFHTLS: report from the Steering Group, DOG activities, data proprietary
time
6.Future
of the CFHT
7.Other
items
1. Technical activities report
SAC received a report
prepared by D. Salmon about on-going CFHT technical activities. Many changes
to the technical staff over the last semester have led to a reorganization
of the previous CFHT technical groups into an Instrumental Group. This
was described during the oral presentation.
Telescope Declination Oscillations:
A report was given about
the continuing difficulties with the declination oscillations of the telescope.These
seem to occur more and more frequently, and sometimes include severe jumps
in declination. Although a detailed analysis of the mechanical structure
of the declination axis has been performed, no satisfactory solution has
been found as of yet.Discussions
with a servo consultant began some time ago but have been postponed recently
because of other higher priority commitments of the technical staff, especially
during the commissioning phase of MegaPrime. SAC is concerned about the
relatively long-term declination oscillation problem: it can induce significant
elongation of the images about 20% of the time, and therefore causes significant
losses in data quality, especially for instruments which do not include
tip-tilt correction.(The oscillations
do not affect AOB observations and should not affect upcoming MegaPrime
observations once commissioning of the camera is complete.).Given
this significant impact on many observing programs, we urge CFHT to increase
their efforts to find a solution to the oscillation problem.
Instruments and detectors:
No important changes
in the instrumental suite occurred this semester.
-
The new MIT-2 CCD has been installed on Gecko/Cafe and is now offered (still
on a shared-risk basis) to observers. Users benefit from very low fringing
amplitudes in the red when compared to the alternative EEV-1 chip.
-
A severe failure of one of the central CCD’s of the CFH12k camera occurred
recently, but fortunately without severe effects on the scientific data.
However a replacement of the chip is expected very soon in order to maintain
availability of the camera for the next several months.
-
MIT CCD’s (1 and 2) are now fully tested and mounted in their own dewars.
MIT-1 awaits a dedicated controller and so cannot be offered at the moment.
Development is continuing.
-
The CFHTIR controller has been upgraded to give a much shorter readout
time.
-
Several failures occurred in the GriF mode installed on PUEO. The Fabry-Perot
was sent back to the manufacturer for repair and is again on the telescope.
An additional unsolved problem is the locking of the mechanical wheel that
occurs only within the cold. Help from the development team in Paris-Meudon
is encouraged in order to make the GriF mode as efficient on the telescope
as originally expected. SAC notes that a large number of nights have been
allocated to GriF for 2003A on the French side.
|
Given the impact of
declination oscillations on most observers, SAC recommends that the priority
for solving this problem be moved to second on the CFHT project priority
list.This change is made with the
understanding that it will not impact the WIRCam development.
Due to the large number
of nights allocated to GriF for 2003A, SAC also encourages CFHT's efforts
to solve the GriF problems, preferably in time for the scheduled 2003 March
run, but certainly by 2003 May.
The top of the new list
of CFHT project priorities recommended by SAC is as follows:
|
Priority
|
Project
|
|
A+
|
MegaPrime
|
|
A
|
Declination oscillations
|
|
A
|
WIRCam
|
|
A
|
GriF
|
|
2. Instruments and projects
1.PUEO NUI
SAC was presented with
a proposal for a workshop for all parties interested in the PUEO NUI project.The
goal of the workshop is to gather together experts in the field of adaptive
optics, as well as potential PUEO NUI users in the Canadian, French, and
Hawaiian communities, in order to discuss whether or not, given the current
orientation of the 4-meter class telescopes and CFHT in particular, such
an upgrade of PUEO is warranted. A tentative program of the workshop was
also presented.
SAC fully supports the
idea of a PUEO NUI workshop. Such a workshop should take place in early
2003 so that a report can be presented at the 2003 May SAC meeting. Members
of the SAC will be available to assist with the organization of the meeting.
2. OHANA
O. Lai presented a progress
report of the OHANA project to SAC. SAC is pleased with the first results
for Phase I of the OHANA project obtained at CFHT during the August engineering
nights.
SAC supports the current
efforts to continue Phase II development of the OHANA project, and also
urges the OHANA team to pursue additional investigations of possible operational
models for the project. SAC also strongly encourages continued experiments
that could put the expected sensitivity limits on a firmer footing.
3. SkyProbe and Seeing monitor
An update of SkyProbe
developments was presented by E. Magnier, with emphasis placed on the two
most recent improvements: a change in the camera with a new device which
does not suffer from the anti-blooming featurespreviously
identified, and (as shown during the SAC summit visit) the relocation of
SkyProbe on the Caisson central of the telescope.Improvements
in the quality of the data and the control of systematic effects are spectacular
and SAC congratulates the CFHT personnel who continue to improve the performance
of this important facility. The implementation of a second camera equipped
with a blue filter is highly desirable, as it should provide a direct estimate
of the sky extinction in addition to the sky transparency provided by the
current one-camera system.
Thanks to the development
of SkyProbe, new contacts were made with a group atthe
IfA (Hilo) in charge of operating a DIMM seeing monitor on top of Mauna
Kea. Combining such a DIMM monitor with a SkyProbe camera may enable the
installation of a fully automated seeing monitor within or close to the
CFHT dome. SAC recognizes that some developments are still necessary to
fully integrate this system, in particular in terms of software development.
This will require some effort on the part of the CFHT technical staff.
|
SAC
recommends that the second Skyprobe camera be installed on the telescope
as soon as possible. It is also delighted in the progress made towards
having a seeing monitor at CFHT.We
strongly encourage the installation of such a fully automated DIMM facility
inside the CFHT dome. In terms of priority in the project list of CFHT
activities, we propose a ranking at the B+ level, i.e. just below EspaDOnS
development. |
4.WIRCam
SAC reviewed the progress
report of the WIRCam project with the newly appointed Project Manager P.
Puget. We are very pleased to see that the project is continuing on schedule.
It is recognized that the detector controller development is currently
close to the critical path and so it is important that this development
be closely followed. According to the present schedule the instrument should
be on the sky by May 2004 and could be offered to the communities in semester
2004B. The SAC applauds the efforts of CFHT to maintain this aggressive
schedule for WIRCam.
SAC also received an oral
report from the Steering Group and continues to encourage more active participation
of their members in the final definition of the camera and filter set.
In particular the choices in the narrow-band filters are still pending
and should be defined very soon.
WIRCam surveys:
J.L. Beuzit reported on the recent “Call for Ideas” for wide field
infrared surveys with WIRCam and the individual proposals were examined
by SAC. More than 15 suggestions had been received at the time of the meeting.
These
involved 3 types of proposals or ideas: some « survey-like »
proposals mostly related to the near-infrared counterparts of the CFHT
Legacy Survey, several propositions of « large » programs requiring
a large amount of time for a dedicated scientific topic addressed by a
dedicated team, and a few PI-like programs which could easily be carried
out through the normal process of time allocation. A brief discussion of
the pros and cons of a legacy-type survey versus several large PI-programs
was conducted, but at this time not enough information was available to
decide between the two options for the use of WIRCam at CFHT over the next
several years. Before any decision can be taken, much more consideration
must be given to this issue by the SAC and the WIRCam Steering Group. SAC
requests as a very first step that the Steering Group prepare a summary
of the submitted proposals, and the overall program requirements such as
the amount of time and the area coverage for each proposal. This summary
will be distributed no later than December 15, 2002 and will be posted
on the public WIRCam
page on the
CFHT web site.
In preparation for subsequent
WIRCam survey discussions, SAC requests that the Steering Group meet early
in 2003 in order to examine in more detail the scientific cases developed
for the “Call for Ideas”, and to propose several alternatives for the best
use of WIRCam in the next 5 years.An analysis of the amount of time acceptable
for each scientific domain as well as of the data analysis requirements
and resources needed to fulfill all of the selected programs should be
produced. Such a discussion must also take into account the programs and
schedules of other large surveys currently in preparation: UKIDSS at UKIRT,
VISTA at ESO, Pan-STARRS at UH, etc.A report from the Steering Group is
expected by mid-March and will be sent to SAC as well as to the national
TAC’s. The TAC’s will be asked for feedback on the desirability of large
programs within the member communities, as well as their opinion on the
organization of the observing time allocated on WIRCam. The results of
this work will then be reviewed at the SAC meeting in 2003 May and a final
recommendation will then be made.
|
A definitive decision
in favor or against large survey(s) with WIRCam can not yet be made.Because
of this SAC requires several actions to be taken by the Steering Group
over the next few months:
–15
December 2002: publication of the list of proposals received after the
“Call for Ideas”, including an homogenization of the requirements.This
list should be posted on the CFHT WIRCam web page and distributed to SAC
members.
–Meeting
of the Steering Group by February 2003 in order to prepare several alternative
proposals for the best use of WIRCAM in the next 5 years in the context
of surveys and large programs. The issue of whether surveys should be run
in PI-mode, or be organized by the Steering Group and SAC, should also
be addressed.
–Preparation
of a report from the Steering Group to be sent to SAC and to the national
TAC’s by mid-March 2003 for scientific evaluation. Feedback from the TAC’s
is expected intime for the 2003
May SAC meeting.
–Synthesis
and final recommendation will be made by SAC during 2003 May meeting |
5. ESPaDOnS
An ESPaDOnS progress
report was presented to SAC by N. Manset. The present schedule sugests
that the instrument will be tested on the sky by mid-2003 and fully commissioned
during the fall of 2003. It should be available to the communities for
semester 2004A, a small delay when compared to the previous schedule. However,
in order to maintain this schedule it was necessary to delay the design
of the thermal enclosure for the spectrograph, with the result that the
enclosure is now considered to be an upgrade of the instrument. SAC is
concerned with the possible degradation of the stability of the instrument
and its scientific performance, at least for some programs.
A discussion was carried out about the choice of
a CCD detector for ESPaDOnS: there is a strong request from the builders
that an EEV CCD (and in particular, EEV-1) be installed permanently on
the spectrograph. It is easy to understand why this permanent set-up is
required but questions arose about the limitations of the final instrument
performance in the red because of strong fringing effects on the EEV CCD’s.
It was also mentioned that some fringing was present with EEV-1 data even
in the blue, although at a substantially lower level. The implications
of this fringing effect should be presented to SAC and to the communities
as it may have some consequences on the way ESPaDOnS will be used.
|
SAC requests an evaluation
of the impact of EEV1 CCD fringing on the performance of the ESPaDOnS spectrograph.
Quantitative reasons as to why EEV1 is the "only" suitable detector are
also requested before this or any device can be dedicated for use on ESPaDOnS.SAC
also requests an evaluation of the scientific impact of a thermal enclosure
(or lack thereof) for ESPaDOnS |
6.MegaPrime
C. Veillet presented
a short update of the MegaPrime integration phase. Final acceptances of
the sub-units have been signed (at the end of May for MegaCam in Saclay,
and at the end of July for the GSFU at HIA). A first engineering run was
carried out in mid-October, and the next two will occur in early December
2002 and early January 2003. A short presentation of the commissioning
plan was presented but is still under development. Although there has been
a shift of a few months in the schedule for MegaPrime compared with the
schedule presented in May, SAC recognizes the desirability of a careful,
detailed integration plan, sub-unit by sub-unit, before final assembly
and the first tests on the sky. SAC encourages the CFHT technical staff
to make every effort to maintain the present MegaPrime schedule. SAC also
asks to be kept informed on progress during the commissioning phase of
MegaPrime over the next few months.
7.NOP
P. Martin presented a
summary of the QSO operations for semester 2002A. Despite a significant
amount of bad weather throughout the semester, a 90% completion rate was
achieved for the A-ranked programs. SAC is very impressed by this result,
and it again demonstrates the efficiency of queue scheduling in completing
the execution of the most highly ranked scientific programs.
Replying to a request from
the SAC, statistics on the image quality (IQ) obtained on the images were
presented and compared to the requested ones. Once again the results demonstrate
the success of queue scheduling: more than 90% of the data have an IQ better
than the upper limit requested!
|
SAC
is very impressed by the quantitative success of queue scheduling operations
as they are currently being carried out at CFHT. SAC therefore urges the
Board to provide additional financial support to continue to ensure the
efficient operation of QSO, especially in the MegaPrime (and WIRCam) era. |
3. Telescope use and scheduling for 2003A
SAC TAC members reviewed
the schedule of the telescope for 2003A. No great difficulties were encountered
with the ranking sent bythe national
TAC’s. An examination of the distribution and evolution of the number of
nights requested per instrument in the French and Canadian communities
shows significant differences: there is a strong interest in high-resolution
spectroscopy (Gecko) from the Canadian community, while the French community
is very interested in high resolution imaging, especially with GriF mounted
on the AOB. This tendency is very significant over the last 4 or 5 semesters
and apparently reflects different uses of the CFH Telescope by twocommunities
with considerablydifferent access
to other astronomical facilities around the world.
4. Evolution of the instrumental suite
An examination of the
present instrumental suite and its evolution for the next 4 or 5 years
was presented by G. Fahlman and extensively discussed by SAC. An estimate
of the technical load on the CFHT staff was taken into account in the discussions.
Concerning the dark time
instruments, the following issues were discussed:
-
CFH12k should not be made available to observers once MegaPrime
is fully integrated and commissioned. In any case, once WIRCam is assembled
on the PF upper end it will not be possible to mount CFH12k on the telescope
(i.e., by mid-2004).
-
MOS/OSIS:This issue is more critical as this instrument competes
directly with MegaPrime, and in particular with the CFHTLS. However, it
is recognized that MOS continues to be a competitive instrument, even in
this era of large telescopes. For example, MOS has a field of view four
times larger than GMOS on Gemini as well as better spectral coverage, so
both instruments are roughly equivalent in terms of performance for some
types of science.This is not the
case when compared to VIMOS on the VLT, but MOS is the only low-resolution
spectroscopic facility available to the French community in the Northern
hemisphere.From the CFHT point
of view the load on the technical staff to maintain MOS/OSIS is not huge,
but continuous maintenance of software, documentation, and the Laser machine
are required.More subtle is the
necessity to maintain CFHT technical knowledge and expertise for this rather
complex instrument.However, given
the fact that the demand for this instrument has been relatively constant
over the last several semesters, at the current time SAC does not believe
that this instrument should be de-commissioned in the very near future.
\
For the bright time instrument,
the situation is the following:
-
OSIS/IR: SAC acknowledges the fact that no proposals have been submitted
for OSIS/IR for the last two or three semesters. Because OSIS/IR does not
compete well with other near-IR spectrographs on large telescopes, we recommend
that OSIS/IR no longer be offered to CFHT users.
-
Gecko: As requested by SAC at the last meeting, an evaluation of
the manpower requirements for maintaining and supporting Gecko was examined.
After the de-commissioning of the UV train and the commissioning of the
fiber link (CAFÉ), it is recognized that the load on the technical
staff is now rather modest and comparable to what is expected for ESPaDOnS.
Moreover, due to the continued strong interest in high-resolution spectroscopy
from the user community, SAC does not believe that the decommissionning
of Gecko should be scheduled before ESPaDOnS is fully tested and operational.
Such a decision is therefore postponed until the user communities indicate
a strong preference for ESPaDOnS vs. Gecko.
-
AOB: At present, most users of PUEO come from the French community,
thanks in particular to the GriF mode. However it is anticipated that without
an upgrade such as the proposed PUEO NUI, adaptive optics at CFHT will
become less and less competitive once most of the 8m telescopes are equipped
with similar facilities.
-
CFHTIR: It is anticipated that CFHTIR will be automatically replaced
by WIRCam as soon as the latter is available.
Among the new developments
anticipated over the next years, a Prime Focus fiber-feed for ESPaDOnS
attracted the attention of SAC.If available in QSO mode, such a facility
would make optimal use of CFHT observing time when seeing conditions are
poor. If such a development is initiated, the desirability of locating
such a fiber-feed on the MegaPrime prime focus rather than the WIRCam prime
focus appears to be clear. MegaPrime is likely to be mounted on the sky
for a larger number of nights than WIRCam, especially during the CFHTLS
era, so it seems rather obvious to suggest this focus as a first priority.
Bad seeing conditions impact optical imaging observations more than near-IR
observations, so this also suggests that a MegaPrime fiber-feed is preferred
to a WIRCam feed.
Finally, again assuming
its availability in QSO mode, such a feed will also effectively increase
the amount of dark time available to MegaPrime users.
|
MOS/OSIS: SAC
does not recommend decommissioning MOS/OSIS at the current time.The
case for decommissioning MOS/OSIS should be revisited if either the required
technical support becomes burdensome or demand for the instrument decreases
significantly.
OSIS/IR: SAC
recommends that OSIS-IR no longer be offered to CFHT users.
Gecko:
SAC recognizes that Gecko may be decommissioned after ESPaDOnS has been
commissioned and shown to be fully operational.We
recommend that a decision on decommissioning be made after the performance
of, and demand for, ESPaDOnS has been demonstrated.
PF
feed for ESPaDOnS: SAC
acknowledges the scientific benefits of having a PF feed to ESPaDOnS to
help make optimal use of bad seeing conditions in QSO.SAC
would prefer to have a PF feed to ESPaDOnS available for use with MegaPrime.
However, SAC recommends that CFHT make the final decision on a PF feed
on the MegaPrime or WIRCAM upper ends based on the level of effort required. |
5. The CFHTLS
C. Veillet reported on
recent activities from the Steering Group including development of the
CFHTLS Web page, the start of the registration process, and the opening
of several mailing lists and the subsequent lively e-mail exchanges. A
meeting of the Steering Group took place at the end of August and a detailed
presentation of the CFHTLS was given at the meeting on « Structure
Evolution and Cosmology » in Santiago in October, with a lot of feedback
from meeting participants. C. Veillet announced that due to his new commitment
as Interim Executive Director starting in January 2003 , he will resign
from the Steering Group.
He proposes Jean-Charles
Cuillandre as his replacement. SAC endorses this choice with enthiusiasm.
The final choice for selected
fields for both the Wide survey and the Deep/SN survey are now close to
convergence, after extensive discussions between the Steering Group and
the participating communities. This choice will be announced on the CFHTLS
Web page as soon as it is finalized.
A Memorandum of Understanding
(MOU) between the three institutions (CFHT, CADC, and Terapix) involved
in the data processing of the CFHTLS was presented to SAC in its draft
form. Comments have already been received from the three institutions.
A few more details have to be completed before the agreement is signed.
In the meantime, preparation of the Interface Control Document (ICD), which
will be attached to the MOU, has progressed well, especially since the
formation of the CFHTLS’s Data Operation Group (DOG). Weekly teleconferences
have led to a better definition of the content of the meta-data distributed
at the same time as the pixel data themselves. SAC is encouraged by the
progress in data processing and distribution for the CFHTLS.SAC
also urges the participating partners to maintain the view of the CFHTLS
data processing and distribution system as a very important collaborative
effort rather than as a set of rigid institutional contracts between partners.
Extension of the Proprietary
Time of the CFHTLS data:
SAC received a detailed
justification of the request for an extension of the proprietary time of
raw and pre-processed data of the CFHT Legacy Survey, unanimously endorsed
by the CFHTLS Steering Group. SAC agrees that such an extension is justified,
both scientifically and technically.SAC
therefore endorses the CFHTLS « 3-2-1 scheme » for the public
release of both raw and preprocessed survey data. The final decision should
be taken at the Agency level.
The UH SAC representatives
expressed concern over the fact that this change in the data access policy
for a substantial fraction of CFHT data was made after the UH community
had decided not to participate in the Legacy Survey.
6. The future of CFHT
The near-term future
of CFHT is mainly related to the instrumentation evolution and was treated
as a full item during the meeting. One can also start thinking about the
extent of service mode operation in the future. Although it is an expensive
operational mode, SAC is convinced that it is very valuable scientifically,
as demonstrated by the present success of NOP operating the CFH12k. The
longer-term future is related to the ng-CFHT activities and other projects
starting within the three communities. SAC recognizes that each of the
member communities is interested in very large optical telescope initiatives
and ackowledges the fact that several projects, which may interest one
or another of the communities, are emerging in the international context.
SAC is convinced that the success of the CFH collaboration has been such
that efforts must be pursued to examine the prospects of a joint project
and encourages a continuation of the existing collaborations between France
(Observatoire de Marseille and Observatoire de Paris-Meudon) and Canada
(HIA).
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SAC strongly recommends
that the CFH communities pursue technical activities jointly in the framework
of CFHT, with the participation of CFHT staff where appropriate. |
7. Other items
Some changes in SAC membership
are foreseen for 2003: SAC members M. Pierre and L. Drissen are leaving
at the end of 2002. New members will be announced in the new year. G. Soucail
retires as SAC chair and will be replaced by D. Bohlender.
A spring meeting is foreseen
on May 16-17 2003 in Toulouse (France).