86th meeting of the Canada-France-Hawaii Telescope

Scientific Advisory Council

Waimea, Hawaii, November 16-18, 2014

Note: The report presented below is the public version of the SAC report; the Board of Directors has reviewed the report and is hereby released as submitted by the SAC, unmodified.

After deliberation at the December 2014 meeting, the CFHT Board of Directors, in consultation with the Executive Director, endorsed SAC’s recommendations 1 through 5 and 7. To Recommendation 6, Future Large Programs, the Board issued a resolution as stated immediately after Recommendation 6 below.

Recommendation 1 WIRCam calibrations
Recommendation 2 MSE and CFHT operations workloads
Recommendation 3 Operational and development priorities
Recommendation 4 Broad bandpass filter for MegaCam
Recommendation 5 Calibration of new griz MegaCam images
Recommendation 6 Future Large Programs
Recommendation 7 Communications between SAC members and CFHT staff

Report of the 86th meeting of the CFHT Scientific Advisory Council,
November 2014

The 86th CFHT Scientific Advisory Council meeting was held in Waimea on 2014 November 16-18. SAC members Hervé Aussel (vice-chair), Pauline Barmby, Magali Deleuil, Thierry Forveille, Andrew Howard, Rodrigo Ibata, JJ Kavelaars, Marcin Sawicki (chair), Gregg Wade and Richard Wainscoat attended the meeting. Wei-Hao Wang from the Academia Sinica Institute of Astronomy and Astrophysics in Taiwan and Byeong-Gon Park from the Korea Astronomy and Space Science Institute attended the meeting as invitees. SAC members toured the summit facility on the first day of the meeting. During the second and third days of the meeting CFHT Executive Director Doug Simons, Director of Science Operations Daniel Devost, and Director of Engineering Derrick Salmon made presentations and participated in the discussions. SAC also heard a report on the Maunakea Spectroscopic Explorer (MSE) project from MSE Project Scientist Alan McConnachie via videolink. CFHT staff attended the open part of the meeting.

1. Telescope use and scheduling report

SAC received reports on Time Allocation and Queued Service Observing (QSO). Weather was typical during 14A and the beginning of 14B, with about one-third of observing time lost to poor conditions. WIRCam was the most affected (losing 40% of time in 14A) followed by MegaCam (losing 31% of time in 14A); ESPaDOnS was less affected (losing 16%). Completion rates for A programs were >80% for all three instruments. Completion rates for B programs varied: 99% for ESPaDOnS, 55% for WIRCam and 48% for MegaCam. All Agencies have obtained approximately 70% of their allocation or more. The two Agencies at the greatest disadvantage for 2014A were Canada and France, with 75% and 68%, respectively, while other national agencies obtained ~90% or greater. Except for the MATLAS large program, the LPs obtained almost all of their allocation (LP Agency completion of 82%). Demand for all three main instruments continues to be healthy, although demand for ESPaDOnS was once again greater than for WIRCam. The SAC has requested a more detailed breakdown of overheads in future QSO reports.

SAC thanks the QSO team for their dedication in ensuring the best scientific use of the Telescope.

2. Operational status


MC/MP suffered a failure in the filter juke-box while using one of the new larger (and heavier) filters. The SAC was happy to hear the damage to the juke-box was only minor and that significant engineering effort is being devoted to ensuring this failure mode does not re-occur. The efforts to further enhance the failure detection system within the juke-box are encouraged.


WIRCAM non-linearity investigations appear to have determined a more complete calibration of the non-linearity of WIRCam pixels. The SAC encourages CFHT to ensure that these improvements in WIRCam calibration are propagated to the archive dataset where feasible.


SAC recommends that past WIRCam program PIs be advised of the improved calibrations when they become available.

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ESPaDOnS continues to be a high-demand instrument on the CFHT. While Gemini may use OPERA for GRACES, the SAC learned that development efforts on OPERA are somewhat slow at CFHT. The SAC encourages the CFHT to find ways to continue OPERA development in a timely fashion, perhaps in co-operation with Gemini, so as to create an open-source data analysis system for ESPaDOnS that makes the capabilities of the instrument fully available.

Dome Shutter

Shutter work is seen as an important activity in maintaining the health of the observatory and the SAC encourages the CFHT to continue their efforts at improving the reliability of the shutter.

TCS Upgrade

The SAC learned during the meeting that most issues with the new Telescope Control System (TCS) have been resolved and the new TCS will likely be in full operation for the start of 15A. This is a great step forward in reducing the failure risk within the observatory.

Mirror Coatings

The primary and secondary mirrors’ coatings were applied during the August shutdown. Initial analysis indicated that this resulted, as expected, in a significant improvement in mirror reflectivity. The SAC encourages CFHT to explore in more detail what can be done to optimize the mirror recoating cycle so as to maximize observing efficiency. SAC commends the observatory staff for their excellent efforts at keeping the observatory running efficiently.

3. Development status report

Dome Vents

The usage of the new dome vents has demonstrated the ability of venting to improve seeing. The data collected thus far show that they allow an improvement of at least 0.1 arcsec in median IQ. This result should be better quantified by acquiring systematic measurements on a longer timeline. There are some concerns about water incursion into one electrical box, the origin of which is still to be determined and fixed. The SAC encourages further efforts towards improving the delivered IQ, such as investigating the redesign of the primary mirror covers (see item 11 in Recommendation #3).


The SAC is concerned with the continued minor delays in the acceptance of SITELLE. SITELLE is seen as holding great promise for use on the CFHT and continued delays in delivery beyond spring 2015 will negatively affect the potential scientific return of this instrument. The SAC is encouraged that the issues currently identified appear to have been resolved and looks forward to the delivery of SITELLE. CFHT is continuing to prepare for the delivery of the instrument to the dome, with work proceeding at a pace that should match SITELLE’s delivery schedule. The CFHT science staff is encouraged to continue to prepare for the arrival of SITELLE to help ensure maximum science impact for this new instrument.


GRACES has been successfully tested with Gemini. A preliminary report on this subject appeared in the May 2014 SAC report and more complete analysis undertaken since that time confirmed the successful test of GRACES with Gemini. A new thermal enclosure for ESPaDOnS was described (and illustrated during the summit tour) that will enable smooth switching between GRACES on Gemini and ESPaDOnS on CFHT. The SAC is of the opinion that ESPaDOnS is likely to continue to be a high-demand instrument on CFHT for some time to come, even into the SPIRou era, and therefore efforts to ensure straightforward transitions between the Gemini and CFHT feeds are strongly supported.


The SAC was pleased to hear of the acceptance of the new MegaCam filters. Their quality is impressive, with very good transmission over the complete bandpass. Once installed, the new filters will allow the use of the full 40 MegaCam CCDs instead of the 36 currently available. The SAC looks forward to the resulting significant increase of the instrument’s field of view in addition to its throughput. Work on CCD readout speed improvement remains pending because of the focus on completing the TCS upgrades and (only recently resolved) lack of staff resources. The instrumental set-up for testing is, however, ready and the SAC looks forward to a report on readout speed improvements at the May 2015 meeting.


SPIRou development is continuing with good coordination between the instrument consortium and the CFHT team. The SAC commends all those involved in making the good communications possible. The various agreements and MOUs are either signed or under review by relevant institutions. The Midterm Review (MTR) will take place in April 2015. However, it is now expected that the expenses covered by CFHT will exceed the $2M contribution to the project. Additionally, there are some delays in the development of the instrument. The first main issue is related to the detector development, which is behind schedule as Teledyne is not yet able to demonstrate its ability to produce science-grade detectors. A newly acquired MBE machine should fix this issue by next spring. The second issue is related to the absence of sub-window capability for the guider IR camera as provided by the manufacturer. The direct consequences of this lack of sub-window readout are currently under investigation by CFHT, ASIAA and IRAP, together with the option of using another camera.


The SAC heard presentations from CFHT Executive Director Doug Simons and Interim Project Scientist Alan McConnachie, who - respectively - described the broad-brush status of the project and the science effort. It is clear that the project is gathering momentum on a number of fronts. The SAC commends all those involved for their dedication to securing this long-term vision for the Observatory, and encourages them to find the balance of efforts that will permit this planning to proceed further while ensuring the continued excellence of short- and medium-term activities at CFHT.


SAC recommends that great care should be given to balancing the available staffing and workloads between MSE and ongoing short- and medium-term activities at CFHT. SAC recommends an inventory of the resources available for both the MSE and short/medium-term activities, and that appropriate actions be taken if a shortfall is found in one or the other.

In conclusion, SAC thanks the CFHT staff for their hard work in developing new capabilities on several fronts.

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4. Operational and development priorities:

The SAC received a presentation of the technical activities report by Derrick Salmon. The SAC extends its thanks to the CFHT staff for achieving significant progress on a number of important projects.


    1.    Normal operations
    2.    Commissioning of the new MegaCam filters and the four “ear” CCDs
    3.    SITELLE comissioning
    4.    Dome shutter work
    5.    TCS upgrade
    6.    MegaCam readout controller
    7.    Dome venting characterization
    8.    WIRCam nonlinearity characterization
    9.    OPERA for ESPaDOnS
    10.   WIRCam data pipeline
    11.   Mirror cover modifications plan for IQ improvement

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SAC recommends that CFHT purchase a broad bandpass filter for MegaCam that is optimized for detection of very faint sources. The SAC recommends that this filter should be similar to the Pan-STARRS w-band filter, but with a shorter wavelength red cutoff, having very high transmission from 400 to 750 nm. The filter purchase should be coordinated with input from JJ Kavelaars and Richard Wainscoat and with reference to the McConnachie et al. instrument proposal of 2013,



SAC recommends that CFHT carefully evaluate how the Pan-STARRS calibration of the entire sky north of -30 declination in the griz passbands can be used to calibrate new griz MegaCam images. This would reduce the need for separate calibration images and increase observing efficiency.

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5. Ongoing Large Programs

SAC reviewed the status reports from the BinaMIcS, MATLAS, MaTYSSE, and OSSOS Large Programs.

All four programs are making satisfactory scientific progress, with their first publications appearing now or expected soon.

The SAC was pleased to receive the nicely detailed report on the status of the BinaMIcS program. The surprising result of very few fossil fields in close binary systems is quite interesting and the SAC looks forward to seeing the interpretation of this result.

We were pleased to read in the MaTYSSE report a synopsis of first published results for LkCa 4, a summary of complementary observations obtained, and the new support of the project's human resources achieved through G. Hussein’s Chaire d’Attractivité.

The SAC was pleased with the progress of the OSSOS Large program, and commends the team for designing a survey strategy that proves robust to worse than average weather. SAC will be very pleased to read the papers that are expected with the next progress report.

The SAC recognizes that MATLAS is a fascinating project that is also observationally very challenging. It requires the very best and most demanding observing conditions available at CFHT and this is the basic cause of the low completion rate of the observations. We encourage the team to concentrate on completing observations of the galaxies in their sample that they have already begun. Ultimately, if additional time is required to complete the project, SAC suggests that the team consider the submission of a PI program.

The SAC reviewed the final report from the completed NGVS program. SAC thanks the NGVS team for a thorough report and commends their science productivity. The report’s comments on survey scheduling prompted a valuable discussion about implications for future Large Programs.

The SAC thanks all of the LP teams for their reports and is looking forward to hearing about the many more scientific discoveries that we hope will be published using the LP datasets.

6. Future Large Programs

SAC recognizes that very large, community-based, proposal-driven programs best allow realization of the full potential of the existing and future instruments of CFHT. SAC feels that such programs provide excellent scientific output and recommends that the majority of the available time of the Canadian and French communities should be devoted to such large programs for the period from 2017A to the possible deconstruction of CFHT, while retaining a reasonable fraction of telescope time for PI-based science. Indeed, the SAC received and reviewed two documents (one for MegaCam, the other for SPIRou) that outlined potential large programs that would require several hundred nights each.

The SAC notes the following points concerning large programs:
• Canada could devote up to 60% of its agency time to LPs.
• France could devote up to 70% of its agency time to LPs.
• Other partners’ allocations to the LP agency are difficult to quantify at this point.
• The date when SPIRou will be available is still not known, but likely to be after semester 2017A.
• The start date of the potential CFHT deconstruction and replacement by the MSE is not known.

At the same time, the SAC notes that:

• To achieve best science results, the LP selection process should be competitive and evaluated by a broadly based LP-TAC.
• LP science must be competitive vis-a-vis PI science and to that end national TACs should be polled about proposed Large Program(s) and provide input on whether the proposed LP science is on par with the best PI programs they send to the telescope.
• The LP-TAC should judge LP proposals on their scientific merit and their feasibility with respect to the average observing conditions as documented in the QSO reports.
• The minimal size of proposed LPs should be small enough to allow the Hawaii agency to contribute significantly to an LP and/or take a leading role, but large enough to result in major scientific impact.


The SAC recommends a staged, two-element call for future Large Programs (LPs).

The SAC recommends that a first call for LPs be issued in early 2015 for selection at the May 2016 SAC meeting. This will be for up to a total of 429 nights contributed by the Canada (60% of national time) and France (70% of national time) Agencies, plus possible contributions from other partners. LP proposals should request at least 100 nights of observing time each, and could request the maximum available time mentioned above. Observations should start in semester 2017A and proceed for at least 6 semesters. LP projects must have sufficiently flexible schedules to accommodate either acquisition of the entire time allocation in the first six semesters (2017A-2019B) or a data acquisition rate that is reduced mid-program with observations extended over a longer timeframe to accommodate the results of the second call for LPs described below.

SAC recommends that a second call for Large Programs be issued once SPIRou has been commissioned and its performance is known. The details of the second LP call will be determined in the future, subject to operational realities in effect at the time of the second call.

Board's resolution in response to Recommendation No. 6 from the SAC

During its 84th meeting, the CFHT Board reviewed Recommendation #6 (above) of the November 2014 CFHT Scientific Advisory Committee report. The recommendation aims at preparing the implementation of Large Programs that will benefit from the new instrumental suite.

The Board recognizes that very large community-based surveys will allow the best realization of the full potential of CFHT with its upgraded instrumentation. It endorses the staged implementation proposed by SAC and the increased commitment of Canada and France on LP time. The Board unanimously agreed that the second call for LP’s should occur one year before SPIRou’s first light on the telescope in order to facilitate the early start of a Large Survey Program amounting to at least 300 nights over the first three years with this instrument. Our expectation is that the call will be issued in early 2017.

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7. Closer engagement between SAC members and CFHT staff

At this meeting of the SAC, CFHT organized the traditional SAC lunch with CFHT staff. SAC believes that such occasions represent important opportunities for the SAC members to communicate with the technical and scientific staff, and to appreciate issues that may not become evident during the more formal parts of the meeting. The SAC feels that having even more opportunities for interactions between SAC members and CFHT scientific and technical staff would be beneficial.


In the spirit of fostering better communications between SAC members and CFHT scientific staff, SAC recommends that (a) CFHT scientific staff present highlights of their research at a ‘science staff symposium’ to occur at each annual Waimea SAC meeting; we foresee these presentations to take about 1 hour in total. (b) A SAC member be invited to present a research seminar before, during, or after the Waimea SAC meeting. In order to get to know the CFHT staff better, SAC also recommends that (c) during the Waimea SAC meetings, some of the technical presentations be made by appropriate CFHT technical and scientific staff members.

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8. Next SAC Meeting

The next SAC meeting will be held on 2014 May 21-22 in southern Ontario, with location TBC