Report of 64th meeting of the CFHT SAC
Waimea, Hawaii, 13-15 November 2003


Recommendation #1 and #2 - MegaPrime
Recommendation #3 - Espadons
Recommendation #4 - Pueo Nui
Recommendation #5 - #6 - #7 - #8 - #9 - #10 - CFHT Legacy Survey - See also the Board of Directors' comments here
Recommendation #11 - WIRCam large joint proposals - See also the Board of Directors' comments here
Recommendation #12 - CFH12K disposition

The meeting was attended by SAC members P. Bastien, J.-L. Beuzit, D. Bohlender (chair), E. Emsellem, C. Ftaclas, G. Mitchell, P. Petitjean (vice-chair), C. Pritchet, and G. Soucail. B. Tully was unable to attend. KAO representative H. Kim and Taiwan representative S. Y. Wang were present as observers. C. Veillet, D. Salmon, J.-C. Cuillandre, O. Lai, T. Forveille, E. Magnier, G. Barrick, W. Rambold, P. Puget, P. Martin, and N. Manset participated in presentations and discussions.

64th SAC Meeting Agenda: 14-15 November 2003

  1. Technical activities report (Salmon)
    1. DEC oscillations
    2. GRIF
  2. Instrument and Project reports
    1. MegaPrime (Rambold/Cuillandre)
    2. WIRCAM (Puget/Forveille)
    3. Espadons (Barrick/Manset)
      1. Project status and schedule
      2. Commissioning
    4. Pueo Nui (Salmon/Lai/Cuillandre)
      1. Project team, plan, and schedule
      2. Flyeyes
    5. Ohana Update (Lai)
    6. CFHT environmental data (Magnier/Veillet)
      1. Second skyprobe
      2. DIMM
      3. Mauna Kea weather services
    1. CFHTLS report (Mellier)
    2. DOG report (Cuillandre)
    3. External review (SAC)
  4. WIRCAM SG (Beuzit)
    1. Filters
    2. Surveys
  5. Telescope use and scheduling (Veillet)
    1. 2004A schedule
    2. Trends in instrument use
    3. Duplicate observations issue
  6. 2004 User's Meeting (SAC/CFHT)
    1. 15-17 May 2004, Victoria, BC
    2. Preliminary program discussions
  7. CFHT Future (Veillet)
  8. Other items
    1. CFH12K disposition
    2. Staff; Astronomy Group
    3. SAC membership; Chairmanship
    4. TAC membership
    5. Next meeting

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1. Technical Activities Report

D. Salmon presented the CFHT technical activities report. No changes have been made to the current project priorities. It was noted that the MegaPrime and WIRCAM projects alone will consume about 80% of CFHT's available manpower for the next year.

SAC was pleased to learn that with the removal of the last summit HP1000 computers a completely autonomous TCSIV system has finally been realized.

Significant progress has been made on reducing the impact of the DEC oscillations on observers, but a complete solution has not yet been found and may require substantial changes in telescope hardware. CFHT will continue to work on this issue and update SAC at the next meeting. SAC congratulates CFHT staff on the progress that as been made and continues to view a full solution of this long-term problem as a high priority as reflected in the current CFHT project priority list.

The defective GRIF filter plane wheel has been sent to Paris for examination by Observatoire de Paris staff and will be returned to CFHT in time for the late 2003B observing runs (which will NOT require full operation of the wheel). It will be returned to OdP immediately after the 2003B runs for final repairs, and as a result will not be available for users in 2004A. CFHT will provide a report at the next SAC meeting.

2. Instrument and Project Reports

· MegaPrime

W. Rambold presented a report on the technical activities carried out by CFHT staff for the MegaPrime project. For the most part the camera is performing quite reliably. The wide field corrector (WFC) is currently believed to be at its best mechanical adjustment. Overall image quality concerns remain and L1 of the WFC is the prime suspect. CFHT will attempt to re-characterize the lens at its normal operating temperature.

In response to a previous SAC recommendation, spare control electronics are now available.

Intermittent failures of CCD#3 will be addressed early in 2004 with help from CEA.

The MegaPrime filter handling mechanism has experienced some technical problems because of the 30-40 filter changes normally made each night. CFHT staff have identified weak links in the design and are currently researching long-term solutions.

Autofocus of the camera is still under development but has made considerable progress and it is hoped that this automation will be concluded in a few months. In any case overheads for guide star acquisition and focusing have been greatly reduced to just a few 10's of seconds on all areas of the sky.

Based on this report SAC makes the following recommendations:

SAC Recommendation #1:

SAC recommends that CFHT proceed as quickly as possible with measurements of L1 of the MegaPrime wide field corrector as a first step in determining the reason for the camera's image quality not meeting specifications.

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SAC Recommendation #2:

SAC recommends that CFHT continue efforts to correct the intermittent failure of MegaPrime's CCD #3, complete implementation of autofocus capabilities, and improve the reliability of the camera's filter handling mechanism.

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J.-C. Cuillandre presented a report on the MegaPrime and Elixir scientific activities conducted by CFHT staff. Of particular note is the release of greatly improved MegaPrime web pages with extremely detailed information on all aspects of observing with the camera.


P. Puget presented a report on progress of the WIRCAM project. Uncertainty remains in the delivery of the detector arrays.Originally expected in early 2004, Rockwell now hopes to deliver all detectors by 2004 April. The ASICS have had warm tests of their functionality; final tests of the packaged prototypes under operating temperatures are expected early in 2004. The report noted that an interim SDSU3 controller might almost reach readout performance goals - 2 seconds for double correlated sampling readout versus the specification of 1.5 seconds.

The delay in the detector delivery has resulted in a 4 to 5 month delay in the project when compared to the previous schedule. The overall project plan currently has on-sky tests scheduled for the autumn of 2004.WIRCAM should be available to observers in 2005A, which means that a call for WIRCAM proposals (see SG group section below) should be made no later than the summer of 2004.

· Espadons

G. Barrick presented a technical report for the Espadons spectrograph while N. Manset presented a report on the Espadons team's commissioning plans and demonstration science programs. The latter will involve two programs: a search for weak magnetic fields in hot stars including OB, Be and Herbig Ae stars, and Zeeman Doppler imaging of a fully convective M dwarf star.

If the current schedule is maintained Espadons should see first light in early May 2004 and commissioning will take place until the end of 2004A with demonstration science currently scheduled in late July 2004. Given concerns in the possibility of maintaining this schedule and CFHT staff commitment to the MegaPrime and WIRCAM projects, SAC would prefer that a call for Espadons proposals not be made until it is certain that the instrument is fully operational.As a result, SAC recommends:

SAC Recommendation #3:

If the current schedule for Espadons is maintained through 2004 February, SAC recommends that Espadons be made officially available to the user community in a call for proposals in semester 2005A. This recommendation will be revisited at the 2004 May SAC meeting.At the discretion of the CFHT Executive Director, for the 2004B Call for Proposals CFHT can consider offering Espadons as a possible alternative to Gecko for successful Gecko proposals.

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· Pueo Nui

D. Salmon and O. Lai presented a report on Pueo Nui. Pueo Nui, which includes the Fly-Eyes upgrade, assumed the status of a true CFHT project in the fall of 2003. Staff commitments to other projects such as MegaPrime have prevented completion of the detailed Pueo Nui study requested at the last SAC meeting, but first efforts in this regard have indicated that the Pueo Nui Workshop's recommended scientific goal of a Strehl ratio of 0.90 in the K band is very ambitious, and possibly not feasible with the relatively simple and fast upgrade of the current AOB system first envisioned.

O. Lai also presented a summary of an alternative two-stage AO system.

SAC discussed Pueo Nui at length. There continue to be compelling scientific and technological arguments for pursuing advanced AO systems at CFHT. Pueo Nui's uniqueness continues to be the capability of high-strehl imaging, extended to optical wavelengths. While the Workshop clearly indicated that scientific targets for the CFHT would be limited, such technology will be of obvious interest to other large telescope projects. SAC therefore makes the following recommendation:

SAC Recommendation #4:

As there continue to be compelling scientific and technological arguments for pursuing the study and development of an advanced AO system at CFHT, SAC recommends that CFHT complete the feasibility study of the originally proposed Pueo Nui project, which consists of an upgrade of the deformable mirror and real-time computer, and the implementation of the Fly-Eyes detector. The main goal of this study is to determine the realistic delivered Strehl ratio of such an upgraded CFHT AO system, and compare these with the scientific goals discussed at the Pueo Nui workshop. SAC would like to review this study at the 2004 November SAC meeting at the latest.

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SAC recognizes that there are additional very interesting ideas from CFHT staff regarding the extension, on longer timescales, of the diffraction limited optical and near-IR imaging capabilities of CFHT, possibly over the entire sky observable from Mauna Kea. SAC feels that it is very important to maintain CFHT staff involvement in such state-of-the-art instrumentation research and development and therefore encourages CFHT to continue to investigate these other AO concepts, such as the two-stage system presented at the current meeting. The SAC would obviously be willing to review any proposal seeking to address these more ambitious goals at a future meeting.

· O'hana

O. Lai presented a brief summary of recent O'hana activities. Phase I work is almost complete with injection tests completed on CFHT, Keck, and Gemini. Phase II work is now progressing quite well. The O'hana beam combiner was successfully tested at IOTA in 2003 June and the CFHT-Gemini delay line is being assembled and tested in Meudon. Fluoride and silicate glass fibers have been manufactured.

Upon successful completion of Phase II work SAC will be required to evaluate plans for Phase III.

· CFHT Environmental Data

E. Magnier presented a summary of recent work on the Differential Image Motion Monitor (DIMM). First tests with the new, customized 14" Meade telescope were carried out on 7 November. Work must still be done to solve remaining problems with control of the Meade's TCS, but much of the functionality required has been successfully demonstrated, including communication between the Meade and CFHT TCS's, conversion of the dome slit coordinates to RA and DEC, slewing the Meade to the selected monitor star, etc. O. Lai will assume responsibility for the DIMM project after the departure of E. Magnier.

E. Magnier also presented a summary of his study of the long-term stability of the absolute photometry from the CFH12K camera. Of note is an interesting long-term (approximately 1 year) variability of a few percent in the zero point that is not clearly related to the primary mirror condition, or other known factors.


G. Soucail, representing the CFHTLS Steering Group, presented SAC with reports of SG group activities as well as reports for the Deep, Wide, and Very Wide survey components of the CFHTLS. C. Pritchet provided a summary of the CFHTLS SNe programs.

Deep Survey

The location of the D2 field has been moved to the COSMOS/ACS survey area at RA ~10 hr.The proposal to move the field was circulated to the CFHTLS email distribution list for discussion, but few comments were made by the member communities.The D2 field is now outside the W2 field.A few SAC members noted that they did not receive the above email.This caused some concern about the completeness of the CFHTLS mailing lists maintained by CFHT, but may very well be an unintended result of some user's SPAM filters.

A frequently updated web page for the CFHTLS Deep Survey can be found at

SN Survey

A web site providing information about the CFHTLS supernovae programs can be found at Of particular note for the SNe program is the fact that a formal collaboration between Canadian and French groups has been established, complete with an MOU.Pain is currently the chair of the consortium.

Each team currently runs its SNe detection pipeline independently. For SN candidates brighter than i'=24 detections by the two pipelines agree very well, and are quite reliable to i'=24.5.80% of all variables at the latter level are real variables, but are not necessarily SNe. It is thought that eventually one pipeline will be shut down to enable a greater concentration on the spectroscopic follow-up.

Follow-up spectroscopic observations are proceeding very well and the survey team believes that the goals of the survey are indeed achievable. In fact, the total number of CFHTLS type Ia SNe observed by 2004 February should already exceed previous detections. The first papers are in preparation, and current plans are for an equation of state paper to be submitted in the spring of 2004.

Wide Survey

Because of the Wide Survey's seeing constraints, this component of the CFHTLS did not ask for QSO time until early concerns with the WFC were eliminated. Also, because this component of the CFHTLS has no time constraints it has been more difficult to obtain the necessary fraction of time for Wide observations without affecting the goals of the Deep and Very Wide components. The observing strategy is still under discussion with the current priority given to large areal coverage versus multi-colour observations. SAC expressed a serious concern that such discussions appear to be taking place only within the SG and have not involved the participating CFHTLS communities at large. SAC reminds the SG that improved communication between the CFHTLS SG and the member communities was an important recommendation (#10) at the previous SAC meeting.

Very Wide Survey

Data have been obtained for the CFHTLS Very Wide Survey at a smaller rate than nominal. Approximately 200 square degrees will have been observed by the end of 2003.30% of the observed fields have been analyzed and 50 KBO's have already been discovered. An up-to-date Very Wide Survey web site is located at

SG Activities

A detailed analysis has been made of the PSF anisotropy of the MegaCam field of view.SAC was told that despite concerns with the MegaPrime WFC, 30 to 32 of the camera's CCD's are within the image quality specifications required for cosmic shear analysis.

A report of apparent fringing in MegaPrime u' images prompted a search for a possible red 'leak' in this filter.No evidence for such a leak has been found.

CFHTLS-related recommendations - See also the Board of Directors' comments here

There continue to be a few concerns related to the CFHTLS science programs, the Steering Group (SG), and the Data Oversight Group (DOG). These have led SAC to make a number of recommendations.

The SAC is concerned about the image quality provided by the MegaPrime WFC. If CFHT's study of L1 of the WFC indicates the presence of a serious problem what is the impact on LS science goals?

SAC Recommendation #5:

SAC requests that the CFHTLS Steering Group conducts a thorough investigation of the impact of the less-than-optimal MegaPrime image quality on CFHTLS science goals and presents a report to SAC early in 2004.

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As mentioned briefly above, the SAC is concerned that some changes in observing strategies are being decided by survey coordinators with no discussion outside the SG, and occasionally only with limited discussion within the SG itself. While SAC believes communication by the SG with the outside communities is improving, it could still be better. Since many users will approach the CFHT home page first for information about the CFHTLS it is important that this web site provide links to the survey web sites given above. Some of the current links on the CFHTLS site have little or no information and should be updated. This leads to the following recommendation:

SAC Recommendation #6:

SAC requests that CFHT ensure that all current information related to the CFHTLS is readily available on the CFHT's CFHTLS web page.SAC is pleased to see the detailed, frequently updated web sites available for the various components of the CFHTLS, and links to these sites should be prominently featured on the CFHTLS entry page.

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SAC expects the first public release of CFHTLS images and data products early in the summer of 2006. A detailed plan for this data release must be made very soon to ensure that queue priorities and schedules are well defined for the next several semesters. This forms the basis of another SAC recommendation:

SAC Recommendation #7:

SAC requests that the CFHTLS SG present them with a summary of the plan for the first CFHTLS public data release in the summer of 2006 well in advance of the 2004 May SAC meeting. Contents of the data release must be discussed with the participating CFHTLS communities. This document should include a clear indication that the queue schedule and priorities can meet the requirements for this data release.

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The SAC is very excited to see CFHTLS science ramping up, especially for the SNe and KBO programs. The committee expects that wider scientific involvement of the CFHTLS communities will increase significantly when Elixir-processed CFHTLS images are released to the CADC and made available for retrieval. TERAPIX should also make their CFHTLS data products available to the CADC (and hence the community) as quickly as possible. Unfortunately no mechanism describing the transfer of data products between TERAPIX and the CADC has been produced and this will make the distribution of TERAPIX products difficult. Because of this SAC makes the following two recommendations:

SAC Recommendation #8:

SAC urges CFHT to provide the CADC with Elixir-processed CFHTLS images as soon as possible and that the CADC also make these images available to the communities as soon as possible. The availability of these data products should then be widely advertised to the CFHTLS communities.

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SAC Recommendation #9:

For the information of the CFHTLS member agencies, SAC notes that an Interface Control Document (ICD) for the transfer of data between the CADC and TERAPIX has not been developed. Until such a document is produced TERAPIX-processed CFHTLS data products will not be available for distribution to community astronomers. SAC recommends that the DOG ensure that such an ICD be developed in a timely fashion.

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SAC also makes the following recommendation to the CFHTLS SG:

SAC Recommendation #10

SAC requests that the CFHTLS SG produce a detailed summary of the progress of the CFHTLS components suitable for review by SAC and the national TAC's. This progress report should be made publicly available by 15 April 2004 to enable possible discussion at the 2004 CFHT User's Meeting. A more formal external review will be conducted in the fall of 2004.

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4. WIRCAM Steering Group

The previous SAC recommendation, based on extensive SG and SAC discussions, indicates that only 30% of the scheduled WIRCAM time per semester would initially be available for WIRCAM 'surveys'. After additional discussion, the SAC and SG do not feel that this represents a significant enough allocation of time to warrant the considerable effort required to attempt to define a Legacy style survey. On the order of 100 WIRCAM nights allocated over a five-year period will simply not be competitive when compared to other large near-infrared surveys currently being planned.

The SG and SAC recognize that there is little support from some member communities for Legacy-style surveys with WIRCAM. However, based on the SG's ?call for ideas? for WIRCAM surveys, there is obviously significant interest in the possible execution of ambitious scientific programs requiring large amounts of observing time over several years, likely involving more than one of the member communities. SAC also recognizes the fact that users of other instrumentation, e.g. Espadons, may also have similar requirements for significant blocks of observing time. However, the current mechanism for assigning significant amounts of time to multi-agency proposals is seen as very unsatisfactory, and has proven to be unsuccessful in the past.

After a lengthy discussion, the SAC agrees that a new mechanism needs to be implemented by the member agency Time Assignment Committees (TACs) and proposes the following as a possible procedure for the review of large, multi-agency (joint) proposals, requiring time over several semesters. This should be reviewed and refined by the national TAC's, the SAC, and the BoD.

SAC Recommendation #11 - See also the Board of Directors' comments here

·SAC defines a ?large joint proposal? as any proposal requesting 30 or more nights over a two-year period and submitted to two or more member agencies.

·Such large, joint proposals should be accepted for any CFHT facility instrument.

·The first Call for Proposals (CfP) for such large programs will be made at the 2004 CFHT User's Meeting on 14 May 2004.

·The large joint proposal deadline will be 1 September 2004.

·Each submitted large program proposal will be reviewed by a joint TAC consisting of equal numbers of members from the TAC's of each participating agency. Members in the joint TAC will be selected by the national TAC chairs and should include a sufficient range of scientific expertise to enable a fair review of all large joint programs.

·The joint TAC meeting will take place on approximately 15 October 2004, just in advance of the national TAC meetings to ensure that the large programs can be reviewed in comparison to normal proposals.

·Accepted large programs will have nights allocated according to the fractional allocations proposed by the applicants.

·The SAC TAC will review time allocations as usual at the 2004 November SAC meeting.

·Large programs requiring more than two years of observations must be resubmitted every two years for review.

·Based on current telescope time allocations additional CfP's for large programs may be made each year.

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5. Telescope Use and Scheduling

C. Veillet presented the preliminary 2004A schedule to SAC after the SAC TAC members had reviewed it. He noted that there has been a significant decline in demand for AOB time from the French over the last several semesters. He also pointed out that MOS runs can have a large impact on CFHTLS science. For the 2004A semester only a single, very highly ranked 5-night Canadian MOS program was scheduled by relaxing the normal ?8-night rule? for instrument set ups.

At the previous SAC meeting the question arose as to how the issue of duplicate observations is resolved in the queue. However, further discussion of 2003B observations with the PI's indicated that no urgent action is necessary since there is currently no real duplication of currently scheduled observations. The situation, however, will be monitored.

6. 2004 User's Meeting

Just prior to the SAC meeting a final selection of the venue for the 2004 CFHT User's Meeting was made. The two and one-half day meeting will be held from 13-15 May at Painter's Lodge, near Campbell River, British Columbia. A web page and First Announcement will be released soon. A brief discussion of the meeting program took place. The first day of the meeting is expected to be devoted to early CFHTLS science. The second day will include WIRCAM and Espadons talks and other contributed science talks. The final morning will be devoted to discussions of CFHT's future and a look back at the 25 years of CFHT excellence.

7. CFHT Future

To provide the SAC with information on which to base possible future instrumentation recommendations on, C. Veillet gave a brief summary of the state of CFHT's past, current, and (anticipated) future operating budget. He noted that the current surplus will be exhausted in FY2007/2008 if agency funding remains at the current level and if all current services are maintained.

At the end of 2005, CFHT instrumentation should consist of MegaPrime, WIRCam, Espadons, Pueo, MOS, and Gecko. SAC will almost certainly have to revisit the issue of decommissioning MOS and Gecko at this time.

He also pointed out that a possible two-stage, or other form of advanced Pueo Nui might be an appealing option for CFHT to retain and use existing technical expertise, increase the contributed R&D efforts of CFHT's member partners, and perhaps open up a new era of optical, diffraction-limited imaging with 4-m class telescopes, possibly including a laser guide-star system.

8. Other items

· CFH12K disposition

C. Veillet gave a brief summary of the current status of the CFH12K camera. An advertisement of the possible sale or trade of the camera for observing time on other telescopes was circulated on the CCD Users email distribution list.Four responses were received from telescope facilities ranging in size from 1.5 to 6.5-m. This led to the following SAC recommendation:

SAC Recommendation #12:

SAC requests that CFHT present a report on options for the possible sale or exchange of telescope time for the CFH12K camera at the next meeting.

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· Staff; Astronomy Group

C. Veillet provided a summary of the status of the search for a new Canadian resident astronomer. A number of good Canadian candidates will be interviewed very soon. Several additional American candidates may be encouraged to reapply for the UH resident astronomer position (to replace E. Magnier) once IfA has posted an advertisement for the position.

· SAC/TAC membership; chairperson

This meeting represented the last SAC meeting for French member G. Soucail and Canadian member P. Bastien. P. Petitjean will assume the role of SAC chairperson on 1 January 2004 and the BoD will select a new Canadian vice-chairperson.

· Next meeting

The next SAC meeting will be held on 17-18 May 2004 at the HIA Dominion Astrophysical Observatory in Victoria, BC.

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