NOTE:
Recommendation #3 includes the result of the Board of Directors'
deliberation.
| Recommendation
#1 |
MegaPrime
- Image
Quality |
| Recommendation #2 | MegaCam
Operations |
| Recommendation
#3 |
MegaCam
runs Board of Directors' Response |
| Recommendation #4 | WIRCam
- Commissioning and data reduction |
| Recommendation #5 | ESPaDOnS
|
| Recommendation #6 | FlyEyes,
Pueo Hou and 'Ohana |
| Recommendation #7 | CFHTLS
- Follow-up to Mid-Term report |
| Recommendation #8 | CFHTLS
- Data release |
| Recommendation #9 | CFHTLS
- Observing strategy |
| Recommendation #10 | Telescope
Use and Scheduling |
| Recommendation #11 | CFHT
Future |
| Recommendation #12 | CFHT
Future II |
The meeting was attended
by SAC members D. Bohlender, C. Ftaclas, J. F. Gonzalez, H. Hoekstra,
G. Mitchell, P. Petitjean (chair), N.
Saint-Louis (vice-chair) and B. Tully. C. Veillet, J.-C. Cuillandre, P.
Martin,
D. Salmon, K. Ho, T. Forveille and G. Barrick participated in
presentations and
discussions.
Derrick
Salmon reported on the technical activities of this semester, including
the integration
of WIRCam and the MegaCam image quality.
Different
maintenance and development activities of the building and telescope
were
described: air compressor and dryer systems, telescope hydraulics, oil
leaks
(epoxy-cement berms installed on 1st floor), soil erosion
issues,
time jumps in the TCS master clock and the WIRCam interface.
The summit is under continuing safety scrutiny
at the moment and this represents a heavy load for many of the staff.
The number of technical failures of the camera
has decreased substantially after constructive discussions with CEA
took place.
A meeting was held between CEA and CFHT engineers in July and
discussions took
place between CFHT and CEA managements. The report on these different
contacts
between CEA and CFHT is not yet available. The final report, when
ready, should
be made available to SAC.
Major operational problems are due to cooling
issues related to the rotating valve, CCD electronics, the lifting arm
for the
fiber rails and to continuing problems with fiber optic connectors.
However,
the global situation is improving. The availability of spares is less
critical
than a few months ago. Problems with
the rotating valve have been investigated in detail and are now mostly
understood.
Contacts between CEA and CFHT should, however,
be maintained. MegaCam is a complex and fragile instrument and,
although SAC is
happy to see that the efficiency of the camera has increased, all
reasonable
efforts should be made to avert a major failure.
The Image Quality in the central half of the
field is much better since L3 has been flipped. The
image quality has been further improved by an increase of the
primary mirror-to-corrector spacing in July 2005 and removal of a residual detector plane tilt in September
2005.
Image-to-image image quality variability remains and is still not
understood.
A model of the focus is in place and
substantially decreases the amount of overheads related to focusing
the
camera. The residuals from the model are approximately 73 microns while
in the
best seeing the accuracy of the focus position is about 50 microns.
New improved recipes for the pre-reduction of
the images within Elixir are being prepared and should be available by
2006A.
New master fringe patterns based on two years of data will be generated
for
different times of the night. The variations of the zero point by about
2 to 3
% from one run to the other is being investigated in collaboration with
the SN
team.
Based on this report SAC makes the following recommendations:
SAC still strongly
suggests that the length of MegaCam runs be kept longer than 14 nights,
and not be interrupted by use of another instrument during dark time.
Much progress has been made since the last SAC
meeting and the instrument should be ready for its first scientific run
in
November. In particular, the four science detectors have been mounted
into the
detector module by Gerry Luppino of GL Scientific and integrated into
the
cryovessel. A new controller has been implemented; RON is of the order
of 30-40
e. A lot of work on the software has been done and a number of problems
have
been addressed and solved. At the end of the October engineering run, a
stable
software and hardware environment had been established. The image
quality of
the instrument is excellent and images of 0.5 arcsecond over the
field-of-view
have been obtained (note that the pixel size is 0.3 arcsec).
Real-time analysis of the data is already
working and the Terapix center is now involved in the implementation of
the
data reduction procedures. However, SAC is still concerned about the
Elixir
environment for WIRCam and would like a detailed report for the next
SAC
meeting. CFHT has more filters available than the number of
filter-slots in the
cryovessel. All filters should be offered to the community. The change
of
filters should however be minimized and if choices have to be made they
should
be made by the TACs and SAC.
SAC is very
pleased with the progress of
WIRCam commissioning and congratulates the teams involved. However, SAC
is
still concerned about resources for data reduction.
CFHT is
encouraged to finish the development
of the Elixir-IR pipeline and to enlarge its collaboration with Terapix
to
provide advanced WIRCam data products (stacked images and catalogs).
Although
only 8 filters can be mounted in the
filter wheels, the complete list of filters should be made available to
the
community in the call for proposal. The final selection of filters for
each semester
will be decided by the SAC-TAC. Changes of filters should be done not
more than
once a semester.
In January 2005, the fibre bundle was damaged
with a loss of a factor 2 in the transmitted flux. The first spare was
damaged
as well and the second spare has a loss of 0.4 mag. New fiber bundles
will be
provided by the Toulouse group, with a new design for the connectors.
They
should arrive early 2006.
Another problem is that there is a shift of the
spectrum on the detector that amounts to about 0.1 pix/night (or 0.3
km/s) that
is not yet understood. Finally, the spectral resolution is not as high
as
expected (it is at present 80000 in the spectroscopic mode “star only”
and
68000 in the other modes).
For 2006A, ESPaDOnS was allocated 19 nights in total (3 for Canada, Hawaii and Taiwan and 10 for France) compared to 31 nights in 2005B. This just reflects WIRCam being made available for the first time. The question of installing a fiber into either WIRCam or MegaCam to feed ESPaDOnS will be investigated. It seems that this could be easier to install in WIRCam. This could be however a nice complement for MegaCam when the moon is up.
SAC
is
pleased with the ESPaDOnS performance
and the scientific results already obtained. The origin of the
wavelength shift
noted over the course of the night and the not quite optimal spectral resolution and throughput should
be
investigated further.
FlyEyes is a demonstration project to estimate the performances of low-noise detectors for AO. Work started again in October and a schedule has been presented for a completion in February 2006.
Two nights are foreseen in April for testing
with Pueo. At the end of July, the staff should know if it is
interesting to
use this cheap and efficient wavefront sensing system.
The project is linked to the Golden Age plan.
The idea is to refurbish Pueo and to add a laser guide star (VASAO for
Visible
All Sky Adaptive Optics). The feasibility study of a new
instrumental
development was accepted by Board to be pursued in 2006.
The Phase II of ‘Ohana is under way.
The delay lines have not been installed yet
contrary to what was planned.
SAC is happy to see that the FlyEyes project is progressing well. They encourage CFHT to pursue this project as future technology for adaptive optics. The goal of an all sky visible AO system is certainly of scientific merit and SAC encourages study of its feasibility. Community involvement should be expanded regarding the possible development of this system.
The repartition of the Wide observations may be
a problem in the near future. Indeed, observations in W3 will soon be
completed
and most of the remaining Wide observations will target W1. This will
most
certainly create difficulties in preparing the observing schedule. The
primary
reason for this situation is the larger area of W1 compared to other
Wide
fields. This larger area was supported by
(i) the existence of a program with a PI at CEA to image a large
field
with XMM; (ii) the fact that there are very few interesting fields
around D4 in
terms of follow-up by other surveys. SAC considers that it is
worthwhile to
engage a discussion amongst the community concerning the possibility of
decreasing the area of W1 and introducing a new W4 field.
SG has asked advice about the first world
release. SG suggests using a subset of T004 expected in June 2006 to be
released world-wide in January 2007. SAC is concerned about the
availability of
T004 for the Canadian-French community. It seems reasonable to release
only
data that have been available to this community for at least one year,
as
originally planned. Therefore SAC asks SG to consider releasing
world-wide data
from T003 one year after T003. The second release could happen six
months after
the first one, based on data part of T004 and so on. This issue could
be
settled during the next SAC meeting.
SAC has discussed the additional 4+4 nights
from the C-F agencies. The general opinion is that major changes in the
survey
following the mid-term review have not had time to yield an
acceleration of the
survey and its prioritized goals. In particular, time is still spent to
finish
the VW observations. In addition, although the efficiency is
increasing, some
time is still needed for the community to be completely reassured that
the
instrument is stabilized. Finally, next semester will be the winter
semester.
To remain consistent with the idea that the survey should be
accelerated, SAC
therefore considers that it is too early to question these additional
nights at
least for next semester. The issue should be re-evaluated in six months
from
now.
For SAC it is clear that the 3-year
observations of TNOs should be re-targeted compared to the original VW
plan so
that they provide TNO recovery. Complementary observations for stellar
proper
motions may be possibly considered at the very end of the survey or as
PI
programs.
Astrometry should not be consider a priority
and such observations can be postponed to the end of the survey or to
PI
programs if need be.
SAC
reiterates its view that SG should focus
on the priorities as given in the mid-term report and recommendations.
SAC is
concerned about the present plan for u-band observations of W1; scheduling problems and tight data
quality constraints make it impossible to complete before the end of
2008B.
This should be investigated by the SG.
u/2 and z/2 could be started now in other fields.
SG must
include the constrains of Queue
observations in its planning. Therefore SAC requests the semester
observing
plan be sent to the SAC, CTAC and FTAC chairs before TAC meetings.
SAC
thinks
that the delay between the mid-term
review and now is not long enough to envisage a change in current
allocation.
Therefore it recommends that the 4+4 nights be allocated for the winter
semester 2006A. If the upcoming semester supports CFHT estimates of 5
or more
validated hours per night, then the extra time should no longer be
allocated.
A first World Wide release of scientific products should be clearly defined for the next SAC meeting. SAC recommends it is based on T0003 and should happen one year after T0003 has been released to the Canadian and French communities.
SAC is worried about the long-term plan as presented by SG in terms of telescope scheduling. It seems that the pressure on W1 is very high and W3 is well under way. It may be more efficient in terms of Q-scheduling to introduce a new field, W4 (of size about 25 square degrees), at about the same right-ascension as D4, and to decrease the size of W1 (by the same amount). SAC believes this change in the strategy will not affect the science goals
and would
result in only a tiny loss of
observing time already invested.
SAC
urges SG
to investigate this possibility
in collaboration with the community via the CFHTLS mailing list and
direct
contacts in particular with CEA. This will be discussed during next SAC
meeting.
Two WIRCam Large Program proposals have been
received. One proposal was on the French side only and the other one
was
Canadian-French. The French TAC would
like the next LP deadline to be postponed in order for proposers to
have time
to get preliminary WIRCam data. This does not take into account that
new
proposers may be waiting for the second call for LPs and therefore SAC
does not
view this as necessary. The French TAC asks for ESPaDOnS to be proposed
in
Q-mode. This has already been discussed several times by CFHT and will
be done
when resources will permit. The Canadian and French TACs ask for the SG
report
to be available before the TAC meeting. SAC supports this request.
Queue observations are working very well and
the validation rate is now above 85%.
The working load is very high however and resources may be short
at some
stage.
SAC suggests that this be discussed by Board
and in more detail during the next SAC meeting. Part of the solution
may be
found in-house.
A report is being prepared for the Board on the use of Director’s Discretionary Time. SAC considers that this report should be reviewed by SAC.
The community
is pleased about the way
Q-observations are performed. However, with two major instruments in
Q-operation, CFHT resources may not be
enough to ensure the highest efficiency of such an observing mode.
Agencies
should be aware that the added pressure on CFHT staff, which would only
be
increased if ESPaDOnS is operated in Q-mode, will most likely require
more
operational resources.
Christian Veillet presented an update of the
plan for the future of CFHT. R&D
could be centered on the refurbishment of the AO system, a possible
laser
guide-star system (VASAO) and the ‘Ohana project.
Christian Veillet has indicated that the long-term future of CFHT is partly linked to the possibility of other partners joining the corporation. About five nights a semester could be made available to the US community through a partnership with NOAO, bringing support for the operation of the Observatory.
SAC supports
efforts by the CFHT director to
prepare for the future.
The
substantial investments made recently to
install unique new instrumentation (MegaCam, WirCam, ESPaDOnS) will
produce
world-class science at CFHT. There is a continuing need to support
efficient
operation and to bring these instruments to
full functionality. It is also important that CFHT maintain a
healthy
level of technological development to attract and retain high-quality
staff.
The ‘Ohana
project is definitely to be pursued
and the VASAO concept seems an interesting possibility to be
investigated in
more detail. SAC still thinks that any further plans should be based on
a
review of the present resources and how they could be adapted to the
future.
The pressure
for observing time from the
Canadian and French communities is very high (larger than three). SAC
therefore
believes the funding from the agencies (either for operational purposes
or
instrumentation development) should be increased rather than selling
observing
time to other partners.
P.A. Duc and C. Gry have been
nominated by INSU
as members of the SAC to replace J.-L. Beuzit and D. Elbaz..
N. Saint-Louis will be the SAC-chair starting
on January, 1st 2006. P. Petitjean will remain member of SAC
through
2006.
The next SAC meeting will be held in Montreal
on May 12-13, 2006.