Report of the 78th meeting

of the Canada-France-Hawaii Telescope

Scientific Advisory Council

Taipei, Taiwan, 18 – 20 November 2010


Recommendation 1 CFHTLS
Recommendation 2 LP Mid-term reviews
Recommendation 3 SPIRou
Recommendation 4 'IMAKA
Recommendation 5 Image Quality improvement project
Recommendation 6 MegaCam and WIRCam filters
Recommendation 7 U-band capabilities of MegaCam
Recommendation 8 Future of CFHT


The 78th CFHT SAC meeting was held at the ASIAA (the Academia Sinica Institute of Astronomy and Astrophysics) in Taipei Taiwan, immediately following the 2010 CFHT Users' meeting. SAC members John Blakeslee, Mark Chun, Thierry Contini, Pierre-Alain Duc, Brett Gladman (chair), Denis Mourard (vice-chair), Coralie Neiner, David Sanders, Gregg Wade and Jon Willis attended the meeting. Michihiro (Hiro) Takami, from the ASIAA, attended the meeting as an invitee. The CFHT director Christian Veillet, Derrick Salmon, and Daniel Devost participated in presentations and deliberations.

Because this SAC meeting occurred immediately following the CFHT Users' meeting, the SAC felt that they had a strong sense of the issues which community members thought were important.

1. Board feedback to SAC

The Executive Director summarized Board feedback on the previous (May 2010) SAC report. As agreed at the previous SAC meeting, it is now standard that the Director will do this at the start of each SAC meeting.


CFHTLS is one of CFHT's major scientific successes. The 2010 Users' Meeting contained many examples of how this data is being exploited by the community. The world release of T0006 was supposed to occur in November 2010. It basically contains the same data set as T0007, but with lower photometric quality. Having two world releases separated by one year might generate some confusion. An immediate world release of T0007 instead of T0006 would make the legacy value and attractiveness of CFHTLS much higher, and would have little impact on the competitiveness of the F and C programs. The T0007 release was not ready by the time of the Users' Meeting as recommended (in the May 2010 SAC report), and thus:

Recommendation 1

SAC recommends that the CFHTLS T0007 be made public to the world wide community as soon as ready and that CFHT generate the relevant publicity for this release.

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3. LP midterm reviews

CFHT had six Large Programs (LPs) operational for 2010B. Four of these had been awarded during 2008 and another two in 2010. The original four LPs were subject to a midterm review as per procedures defined at the time of implementation and in recommendation 2 of the May 2010 SAC report. In fact, the Pandas LP finished collecting its entire allocation during the 2010B semester, so there are only five LPs that will continue running, up to the firm end date of 2012B (when the LP agency created for start in 2008 ceases to exist). At the May 2011 meeting, SAC will discuss the option of issuing another call for LPs; such a call would be made at the very end of 2011 or start of 2012, for programs that would begin 2013A.

The two newest LPs have not completed a first semester yet, so SAC did not have status reports from them. SAC had no concerns about the recent progress of the four original Large Programs. These four LPs made requests for additional time (an option defined at the time of implementation back in 2008, with defined criteria). SAC made its decisions on these criteria using the midterm reports, input from the national TACs, and the desire that no requests continue beyond the pre-defined end date of the Large Programs (see, for example, SAC Recommendation 12 of the May 2007 SAC report).

Recommendation 2

Award 38.5 hours of additional time to the NGVS LP. The additional allocation will be distributed across the 2011B, 2012A, and 2012B semesters at the team's discretion; the team must communicate their choice on the time distribution to CFHT by Jan 15/2011.

For the May 2011 meeting, all five LPs should send progress reports (with copies to participating national TACs) to CFHT, who will forward them to SAC by April 15/2011. The LPs are also responsible for submitting their RA pressure and constraints for the 2011B semester to CFHT by Jan 31/2011 for inclusion in the 2011B call for PI proposals. SAC requests CFHT send reminders to the teams by Dec 31/2010.

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The CFHT executive communicated that, as of Nov 20/2010, not all documents for the Phase A contractual requirements have yet been supplied. However, SAC felt that it had enough information to make a scientific judgement.

Recommendation 3

SAC feels that the stated SPIROU science case and delivery schedule would bring a compelling and timely capability to CFHT. SAC recommends proceeding with a Phase B study once the team successfully passes its Phase A review and addresses the remaining technical and project management concerns to the satisfaction of CFHT. The instrument is technically challenging and SAC is concerned that if the schedule slips or if any of the stated technical requirements (e.g. RV precision of 1 m/s, polarimetry, K-band, and R~70k) are not met, some elements of the SPIROU science case will be seriously degraded with respect to funded competing instruments. SAC will reassess the science case and delivery schedule at the conclusion of the Phase B study.

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SAC and CFHT were very pleased with the quality of the Phase A documentation which was received and thanks the Gyes team for their clear effort to produce a Phase A study in a short amount of time. SAC feels that the core science case about chemical tagging and Galactic structure, as well as some of the related science such as the 3D ISM mapping, is strong and interesting. Clearly Gyes is the kind of instrument needed to address this type of science. However, Gaia data will be open to the world community and other similar instruments such as Hermes, which will be on the sky at AAT in 2012 and has comparable capabilities to Gyes, will start to harvest much of the science case up to 4 years before Gyes. This strong competition makes the case for building Gyes scientifically less attractive to CFHT.

Based solely on the total science case and community interest, the SAC ranked Gyes behind Spirou in terms of the science potential the instruments would bring to the observatory.

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SAC absorbed the most recent 'Imaka input from the team and community at the 2010 Users' Meeting.

Recommendation 4

SAC recommends the 'Imaka team submit an application for a Phase A study to CFHT by March 31st 2011, to be reviewed during the May 2011 SAC meeting for Board consideration in June 2011. This application should include a revised science case based on the current nominal performance estimates. SAC also recommends that the Board continue funding the 'Imaka feasibility study to this date.

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7. Image Quality improvement project

There were strong expressions of support at the 2010 Users' Meeting that IQ improvement be treated as a priority. All current and near-term instrumentation will benefit from this project.

Recommendation 5

SAC recommends that CFHT initiates a multi-faceted project with the aim of improving image quality (IQ) while minimizing telescope down-time.

These efforts include several activities to address a number of different contributors including:

  1. Continue dome venting progress.
  2. Identify and mitigate sources of waste heat in the dome.
  3. Paint outer dome skin with low-emissivity paint (probably as vents are installed).
  4. Explore options for on-site refiguring of the primary mirror.

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8. MegaCam and WIRCam user-requested filters

SAC recognizes that there are potentially compelling science cases for using imaging filters beyond those currently available for both MegaCam and WIRCam. The opportunity exists for PIs to use their own filters in either of these instruments for their science programmes, or to request that CFHT purchase general-purpose filters that would be available to the community. However, PIs should recognize that installing special-purpose filters in WIRCam is complex and time consuming because it involves warming up the instrument, and thus can only be done once per semester; a PI programme must therefore be very highly rated to justify such an undertaking due to potential impact on other programs. The installation of MegaCam filters is more straightforward and can be accomplished between dark runs.

Recommendation 6

SAC recommends CFHT advertise to the user community (as part of the 2011B proposal call) that users have the opportunity to propose that the observatory acquire additional general-use filters and that they may propose to employ their own special-purpose filters in MegaCam or WIRCam.

SAC will review any proposals for the purchase of such filters and make recommendations to the Board based on the proposed science cases. In some cases it may be more appropriate for PIs to purchase filters for specific science cases, but others may be of high-enough community interest that CFHT purchase of the filters for community use is justified. The case for the improvement of the current u-band capabilities is already clearly more advanced.

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9. U-band capabilities of MegaCam

Recommendation 7

SAC encourages CFHT to produce a technical proposal for upgrading the u-band capability of MegaCam, after engaging the relevant CFHT users to provide an associated science case. SAC anticipates reviewing this proposal at the May 2011 meeting.

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10. Future redevelopment of CFHT

SAC recognizes the paramount importance of maintaining the long-term scientific competiveness of the CFHT site. In particular, SAC noted the strong show of interest and support for a long term CFHT future expressed by participants in the CFHT Users' Meeting. While the exact form of a future CFHT is open to consultation, SAC agrees that this may involve eventually replacing the current telescope with a new facility.

However, SAC considers that any long term plan for the CFHT be distinct from the current new instrument plan and should not impact adversely upon their scientific exploitation. The long lead time involved in such an ambitious undertaking makes the timely consideration of such a proposal an important factor. SAC is aware that the decision to upgrade the CFHT site will be based upon due consideration of the relevant scientific, technical and financial implications of such an undertaking. In addition, the scope of such a project may necessarily involve the strategic realignment of the CFHT partnership. SAC also recognises that the question of the long-term future of the CFHT ultimately rests with the national agencies. One method of addressing this question would be to issue a call for comprehensive and detailed project concepts.

Recommendation 8

SAC therefore recommends that the Board urge the CFHT agencies to begin now an investigation of the relevant aspects of a long-term plan to upgrade the CFHT facility.

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11. Operational Priorities

SAC recommends the current CFHT operational priorities be:

  1. Operational aspects of current instrumentation
  2. Finishing the Observatory Automation Project
  3. Image Quality Improvement Project (IQUIP)
  4. SPIRou
  5. SITELLE Phase B
  6. IMAKA feasibility study
  7. U-band MegaCam

12. May 2011 SAC meeting

The next CFHT Science Advisory Council meeting will occur in mid-May 2011, hosted by Thierry Contini, and will be held in Toulouse or its environs.