89th meeting of the Canada-France-Hawaii Telescope

Scientific Advisory Council

Nice, 5-6 May, 2016

Note: The report presented below is the public version of the SAC report as amended by the CFHT Board of Directors.

After deliberation, the CFHT Board of Directors has endorsed SAC’s recommendations No. 8, Acceptance of Large Programs, 2017A-2019B

The remaining recommendations included in the report will be discussed at the next quarterly Board teleconference in July 2016.

Recommendation 1 Fast-Read Mode MegaCam
Recommendation 2 SITELLE time allocation and performance
Recommendation 3 SPIRou - procurement of detector
Recommendation 4 Speed-ups in the observing sequence
Recommendation 5 Overhead times - phase 1 and 2
Recommendation 6 Default mode for MegaCam and ESPaDOnS - 2017A
Recommendation 7 Operational and development priorities
Recommendation 8 Acceptance of Large Programs, 2017A-2019B
Recommendation 9 GRACES calls for allocation of time 17A and 17B

Report of the 89th meeting of the CFHT Scientific Advisory Council,
May 2016

The 89th CFHT Scientific Advisory Council meeting was held in Nice on 5–6 May 2016. SAC members Hervé Aussel (chair), Stéphane Courteau, Magali Deleuil, Tristan Guillot, Andrew Howard, JJ Kavelaars (vice-chair), Nicolas Martin, Kim Venn, Richard Wainscoat and Chris Willott attended the meeting. Jiasheng Huang from the Chinese Academy of Sciences South America Center for Astronomy, Yen-Ting Lin from the Academia Sinica Institute of Astronomy and Astrophysics in Taiwan, and Eder Martioli from Laboratório Nacional de Astrofísica sin Brazil attended the meeting as invitee. The CFHT Executive Director Doug Simons, the CFHT Director of Science Operations Daniel Devost, the CFHT Director of engineering Derrick Salmon, CFHT Optical Engineer Gregory Barrick and CFHT Software Manager Kanoa Withington participated in presentations and discussions.

During the meeting, SAC heard a detailed update from the CFHT Executive Director on the evolution of the political situation in Hawaii regarding present and future developments of astronomical facilities at the summit of Maunakea. Support for astronomy among the communities is paramount if important steps such as a new lease beyond 2033 are to be adopted in a timely fashion for the MSE project to proceed. SAC thanks the CFHT Executive Director and its staff for their repeated efforts to engage the communities in Hawaii in shaping with CFHT a common future.

SAC invited associate representatives from Brazil, China and Taiwan to comment on the interest of their respective communities for CFHT present and future instrumentation.

CFHT Users Meeting

SAC meeting was held following the three days users meeting in Nice. SAC was pleasantly surprised by the assiduity of the audience and also impressed by the scientific breadth of the scientific presentations, highlighting the continued relevance of CFHT today. SAC expresses its gratitude for the great support from CFHT and OCA staff in making this meeting a success. LP teams meetings after the Users' Meeting kept people there and brought more people to the UM, which is good. SAC suggests CFHT provides some measure of financial support (for example by subsidising the cost of additional conference rooms) to facilitate these meetings taking place and encourage them in the future. SAC noted discussions were rather tame during the meeting and discussed ways to improve this, such as shortening the allocated presentation times..

The next Users' Meeting is expected to take place during the first half of 2019, after two years of execution of the Large Programs decided to start in 2017A, and nominally after the first light and science verification of SPIRou.

Development Status Report

MegaCam upgrades

MegaCam continues to be a workhorse instrument for the CFHT. The CFHT staff are to be commended for their success in maintaining this high-impact instrument. CFHT presented to SAC the outcome of their investigation of improving the readout speed of the camera. SAC was pleased to learn that the camera could be operated in a fast-read mode that would be easily implemented and have minimal impact on the scientific value of observations.

SAC was also informed that u-band is now nearly as efficient as is likely possible. However, there may be opportunity for changing the dewar window to allow better u-band transmission.


SAC recommends CFHT to:

  • continue to pursue implementing a fast-read mode on MegaCam for all filters and to provide a report for the November 2016 meeting for implementation in 2017A.
  • investigate the dewar window and implement changes needed to improve efficiency prior to the start of CFIS.

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SAC was impressed by the quality and breadth of the science commissioning data that was presented at the CFHT UM and the promise of the instrument. SAC thanks the SITELLE team and the CFHT for their efforts. Two problems in need of further investigation remain: the image quality (IQ) at the edges of the field, and the modulation efficiency (ME) at large Optical Path Difference (OPD), that could decrease the instrument’s efficiency in its highest resolution. SAC notes that the LP results for the SITELLE proposals do not reflect all the exciting science that this instrument allows and the *community's unwavering interest for it. The absence of SITELLE LPs for 2016 largely result for the short time window between SITELLE commissioning and science verification and the LP call deadline. SAC wishes to bolster SITELLE's momentum and encourages the SITELLE team* to publish and disseminate the SV results promptly.


SAC recommends CFHT to:

  • If not enough PI time to warrant a SITELLE run is allocated by TACs for SITELLE in 2016B, SAC recommends that a SITELLE Science Verification second run (3–5 nights) with a broad range of science including Galactic and extra-galactic science is scheduled on the telescope out of available time as deemed by the Executive Director. This run would have no proprietary time and be opened to the CFHT community.
  • Investigate the IQ and ME problems of SITELLE.
  • Processed versions of all SV data should be made available to the whole community before the 2017A call for proposal.
  • Demonstrate that SITELLE data can be reduced and distributed by CFHT staff by the next SAC meeting in November 2016.

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SAC notes the lack of an MoU between CFHT and U. Laval for ongoing support.


SAC was pleased to have a detailed presentation by SPIRou’s the Project Manager. The presentation provided a good overview of the instrument, and the project timelines with the integration, test and validation phases. The instrument development appears to be on track. SAC was pleased to see that CFHT found a solution to supply an engineering grade detector. The fifteen months required for the manufacturing of the science detectors is the major risk of delay. The use of engineering detectors for the pre-shipment integration and acceptance tests at IRAP allows to mitigate the risk and avoid adding months of delay. Additional fund from UdM/CFI provide contingencies that might help to solve/mitigate any unexpected issue that might arise during the instrument development. SAC expresses its wishes for having an update of SPIRou status given by the SPIRou team at each of its meeting.


Given the tight schedule for the procurement of the detector and the scheduled date of first light, SAC recommends that CFHT and the SPIRou teams take all steps necessary to make the process as efficient as possible.

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SAC acknowledges the Board recommendation for a call for LP one year before SPIRou will arrive on sky. SAC also notes that the SPIRou schedule and board recommendation would result in issuing the call before the instrument’s expected performance is known, i.e. before the Acceptance and Integration Tests at IRAP, which would make it hard for teams to propose realistic programs. SAC will revisit this issue at its next SAC meeting when more is known about the result of the early phases of the detector procurement. Should the Integration and Acceptance tests at IRAP be delayed beyond SAC May 2017 meeting, SAC is willing to organise a special teleconference with the team when tests are completed in order to avoid further delays until its next meeting.


SAC heard from MSE Project Scientist Alan McConnachie on plans to involve the CFHT agencies more directly in the MSE decision-making processes through revisions in the governance structure. The excellence of the MSE science case was also highlighted, based on reports from the international community which are also now prioritising this capability (USA in the Elmegreen report, ESO in an upcoming white paper by Richard Ellis, and the Australian decadal plan).

SAC supports McConnachie's plans to publish the MSE science cases in an astro-ph paper. Conceptual design studies will primarily be used for the baseline costs by the Project Office, but also can favour those agencies when contracts are prepared. SAC recognises that MSE has the additional benefit of energising the technical staff with a new and interesting project, which benefits CFHT through the retention of these very talented people. SAC is however concerned that MSE uses the full development fund of CFHT.

Overall, SAC thanks all the CFHT staff and instrument teams to make all these developments possible.

Operation status and upgrades

SAC was given a report on operational status and upgrades, and wishes to thank CFHT staff for their great work in providing our communities with an excellent facility.

The speed of the observing sequence for MC/MP was discussed. Two related issues that may provide an improvement in observing efficiency were considered:

  • speeding up the filter exchange system, which currently requires about 2 min;
  • implementing a calibration process to make use of in-field standards via the PS-1 catalogue such that less observing time is spent calibrating observations with no loss of scientific value.


SAC recommends that CFHT continue to pursue speed-ups in the observing sequence and investigate switching to in-field calibration for MC/MP observations.

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For WIRCam, Pascal Fouqué provided at the UM a detailed analysis of the observing overheads and lost time during a typical night. For some observing modes involving large dither patterns, the Phase 2 time charged to the PIs is underestimated, and this explains the lower efficiency on the sky of the instrument.


SAC recommends the implementation of different overhead times depending on the observing strategy in phase 1 and 2 so that the PH2 time charged to PIs reflects more closely the actual overheads of their programs. This change should be made in time to be used for semester 2017A.

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For ESPaDOnS, tests of the SNR QSO mode have been conducted with success in 16A. It is also demonstrated to work with MegaCam.


SNR QSO should become the default mode for MegaCam and ESPaDOnS starting from 2017A. Program requesting classical mode should justify their request.

At the UM, Simon Prunet presented ideas to improve the overall observing efficiency by using an automatic scheduler. SAC is keen to see these ideas come to fruition.

Operational and development priorities


SAC recommends the following work priorities for the coming months:

    1.    Normal operations
    2.    SITELLE IQ improvement and modulation efficiency
    3.    SPIRou development
    4.    PH2 improvement
    5.    SITELLE Software
    6.    OPERA Development
    7.    Observing efficiency improvements
    8.    Mirror cover for IQ improvement

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In addition to the above work priorities SAC also notes the importance of the MSE project. This project runs in parallel to CFHT operations and development work and care must be taken to not let it affect this work.

Telescope use and scheduling

SAC received reports on Time Allocation and Queue Scheduling. Instruments user trends show that WIRCam demand is declining while ESPaDOnS is rising, but the trend lacked a synthetic analysis. Are these variations also present at the time request level, or are they the result of the time allocation process ? A synthetic analysis of the distribution of time requests and allocations amongst the various typical science cases of each instrument and their evolution would be some useful information that should be provided to SAC by CFHT science operations, in addition to the plain accounting presented. This is especially important at a time when no SAC member from Canada also sit on the Canada TAC, which makes difficult for SAC to figure out this information internally.

Semester 2015B was very similar to 2015A, with an average time loss to weather of 25%. SAC commends the CFHT in keeping the time lost to technical problems at a very low level of 1.3%. SAC noted the very low amount of hours validated for C time programs this semester, compared to previous semesters. QSO explains this fact by having C programs requesting too good conditions for low priority observations.

Ongoing Large programs

SAC received reports from all Large Programs currently executed at CFHT and benefitted from their presentations at the Users Meeting. SAC reminds the PI of these programs to adhere to the posted deadlines for their reports, so that all the material is available before its meeting. All the programs are making good progress toward their completion in 2016B. SAC will provide their PIs with an individual feedback.


Unfortunately, there was no time to hear about MSE progress during the meeting. However, SAC is looking forward to hearing a full progress report on the MSE project at its next meeting.

Large programs starting in 2017A

CFHT received eight proposals for large programs, two for each instrument offered. The oversubscription is a factor 2.44 on the 429 nights reserved for the call by the Canada and France agencies. Three proposals requested also allocation from the University of Hawaii, one from Brazil and one from Taiwan.

The proposal evaluation process followed the procedure described in recommendation #15 of SAC report from November 2015. Proposal were reviewed by 2 to 3 external non conflicted referees, and graded by each agencies TACs, where only non-conflicted members were allowed to vote. TAC members who were PIs of large programs did not participate to the discussion. The grades were collected by a Large Program Panel consisting of three members of each of the Canada and France agencies, one member from University of Hawaii agency and three members at large nominated by CFHT. On the dark time, the two MegaCam proposals were ranked above the SITELLE proposals by the C and F agencies. On the bright time, there was a consensus on the quality single “small” proposal, where the University of Hawaii was also agreeing to allocate time.

After each SAC member stated their conflict of interests, SAC adopted the Large Program Panel proposal, and limited its discussion to the tuning of the relative priority of the two MegaCam proposals.


SAC recommends the acceptance of three large programs for execution starting in semester 2017A.

  • 17AP001 VESTIGE on MegaCam with an allocation of 50 nights in equal share from the Canada and France agencies, corresponding to the central part of the Virgo cluster.
  • 17AP002 CFIS on MegaCam with an allocation of at least 271 nights in equal share from the Canada and France agencies.
  • 17AP008 CFHT Infrared Parallax Program on WIRCam: with an allocation of 60 nights, 30 from the University of Hawaii, and 15 from both the Canada and France agencies.

SAC recommends that the remaining 78 bright nights not used in the recommended allocation be returned in equal share to the Canada and France agencies.

SAC stresses that the afore list is not rank ordered. In particular, regarding dark/grey time,SAC recommends that at the Right Ascension of 12 hours corresponding to the Virgo cluster, both program should proceed at the same pace. SAC will possibly revise this recommendation in future semesters and give priority to one program over the other, depending on their progress.

SAC recommends that these Large Programs be allocated a total number of nights over the course of their execution, and their semester per semester allocation in hours be determined by the updated efficiency of MegaCam at the telescope: as SAC foresee a potential improvement in the observing efficiency with MegaCam due to the small number of filters used by these large programs, combined with the ongoing effort to upgrade MegaCam and the queue scheduling, this will allow both PIs and LPs program to benefit from these improvements.

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The University of Hawaii has expressed its interest in joining the CFIS collaboration, where several researchers are conducting similar programs on smaller scale, and could contribute to the CFIS time allocation. SAC encourages both parties to find an agreement allowing for an increased CFIS allocation.

GRACES Proposals Evaluation process

The combined amount of time saved by the use of GRACES at Gemini will be large enough after 2016B for the partner agencies to start offering this time to its communities. Both the Canada and University of Hawaii are already part of the Gemini international TAC, and their respective share of the time gained trough GRACES will be merged to their normal share. France could offer 2 nights on Gemini in both 17A and 17B to its community. In order to maintain the flexibility of Gemini operations, France time share could be added in the Canada pool, respecting the relative fractions of priority 1, 2 and 3 time. The proposal can be evaluated by the France agency TAC, and their ranking communicated to the CTAC superchair. Canada has also kindly offered to provide technical support to french astronomer for their phase 1 and 2, as they do for their community.

Taiwan has also expressed interest in being able to propose for time on Gemini. The Executive Director has remarked that no document describe formally how the Gemini time is to be shared.

In order to allow for a call to be issued the following steps have to be completed before:

  1. CFHT to discuss with Gemini whether the GRACES payback time can be used in regular queue mode (preferred) or whether some other mode such as a CFHT mini-queue on some classically scheduled nights must be used.
  2. CFHT to determine with Gemini the conversion factor between nights and hours of Gemini telescope, the formal time accounting unit at this facility, as well as the corresponding ratio of priority 1, 2 and 3.
  3. CFHT and the BoD to determine the respective allocation from GRACES for each agency and possibly the cost for associates.
  4. Organize with Canada TAC and Gemini to identify non Canada proposals that would be treated as Canada by Gemini, how to transmit them to the relevant TAC, and get back the results to the Canada TAC chair for the Gemini ITAC meeting.


SAC recommends the previous action to be taken so that two calls with equal amount of time can be announced in 17A and 17B in the participating non Canada and non UH agencies.

alt: SAC recommends that CFHT establish the process for use of the accumulated GRACES payback time, and that the accumulated observing time should be used in equal amounts in the 17A and 17B semesters.

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Next SAC Meeting

The next SAC meeting will be held at CFHT headquarters, Waimea, Hawaii, on November 15-17, 2016. On the occasion, SAC would like to continue with the format started for the November 2015 SAC meeting allowing for more interactions between CFHT staff and SAC (see recommendation 7 of the May 2015 meeting).