93rd Meeting of the Canada-France-Hawaii Telescope

Scientific Advisory Council

17 - 18 May, 2018, Strasbourg, France

After deliberation during its Quarterly Report-II 2018 teleconference, the CFHT Board of Directors, in consultation with the Executive Director, endorse the following SAC recommendations:

Recommendation 1 Investigation of Refurbishment of Coating Chamber
Recommendation 2 Upgrades to SPIRou - Y and J bands
Recommendation 3 Laser Frequency Comb Availability
Recommendation 4 SITELLE Camera: Optical Characterisation and Potential Upgrade
Recommendation 5 MegaCam SLINK Controller Issues
Recommendation 6 French Programs on Gemini
Recommendation 7 Completion Policy for Large Programs

Report of the 93rd meeting of the CFHT Scientific Advisory Council,
May 2018

The 93rd Science Advisory Council meeting was held at the Observatoire astronomique de Strasbourg, on 17-18 May 2018. SAC members Anthony Boccaletti, Stéphane Courteau, Emanuele Daddi, Tristan Guillot (vice-chair), David Lafrenière, Nicolas Martin, Roberto Mendez, Kim Venn, Richard Wainscoat and Chris Willott (chair) attended the meeting. Keiichi Umetsu from Academia Sinica and Jiasheng Huang from NAOC also attended. The CFHT Executive Director Doug Simons, the CFHT Director of Science Operations Daniel Devost and the CFHT Director of Engineering Andrew Sheinis participated in presentations and discussions.

SAC heard an update from Director Simons on the situation on the Big Island of Hawaii. The ongoing volcanic activity at Kilauea is a concern for those living on the island including observatory staff. To date CFHT has not been affected by earthquakes or volcanic emissions. The political situation of astronomy on the island is still uncertain as there are ongoing legal challenges to the TMT project. SAC was encouraged to hear that the first step in a new master lease agreement for the Maunakea Observatories, the EIS, is now underway. We continue to support the efforts of CFHT staff in engaging the community and showing the positive influence of astronomy. In particular, the Maunakea Scholars program is expanding to all the Hawaiian islands and has generated a lot of positive media coverage.

SAC was pleased to see the ongoing efforts to renew associate partner agreements for China, Taiwan and Brazil and appreciated attendance at the meeting of representatives from two associate partners.


The actions of CFHT and the MSE project office in attempting to broaden the MSE partnership is encouraging. The positive dialogue opened with NOAO/NCOA and Texas A&M University in the US, as well as with numerous Chinese institutes has already translated into a large number of astronomers from these communities joining the MSE Science Team. SAC welcomes the drafting of the Statement of Understanding that should be signed by the MSE partners when MSE enters its pre-construction phase.

Operations Status

SAC was informed that CFHT has upgraded its closed-cycle cooling system. SPIRou adds 10 kW to the 10 kW load already produced by MegaCam and WIRCam. The new system has a capacity of 30 kW, and will provide costs savings. It provides an extra 10kW of capacity for future instruments.

SAC learned that apparently temperature related high-current draws on the declination axis have been traced to the declination wrap. The declination wrap is massive and some wires become taut at high declinations. Cables within the declination wrap have been surveyed, and extraneous cables identified for removal. A better means of support is also being investigated.

SAC was informed that existing balance weight motor control system, solenoid control system and encoder readout system, better known as the RBUS control system is being replaced with an Ethernet equivalent. The aim is to reduce dependencies for the Telescope Control System with the aim of future improvements.

SAC was also informed of improvements being made in GPS timekeeping. SAC appreciates these efforts because precise timing is important for a number of scientific projects, including astrometry of moving objects.

SAC was informed that CFHT staff had investigated options for upgrading the mirror coating system. The underlying concern is that many of the filament mounting posts in the chamber are cracked, and the cracks have been widening over time. It may not be possible to fire the chamber more than a handful of times before one or more posts fail altogether. In addition, SAC had asked CFHT staff to investigate the logistics and benefits of shortening the coating cycle from 3 years to 2 years. A more frequent coating cycle will require that the chamber be refurbished sooner.

SAC was informed that the likely gain in effective observing time by reducing the cycle time to 2 years was 4.25 nights. This number is based on the projected mix of instruments on the telescope. u-band MegaCam observations are very sensitive to the age of the coating, whereas infrared observations with WIRCam and SPIRou are much less affected by the age of the coating. CFHT staff have not yet evaluated the additional risk to the telescope involved with a faster coating cycle. The cost of upgrading to Magnetron was found to be similar to the cost of a new chamber, and as a result, this option is not being pursued.

SAC was informed that refurbishing the existing system is a project that can be done in-house. The chamber takes 112 filaments, each of which requires two mounting posts. In order to refurbish the system, 224 new post caps would need to be manufactured. The old mounts would need to be cut away, and new caps brazed in place. This is within the scope of the technical staff at CFHT, but is a project that would take tens of months to complete.

SAC also discussed the impact on the coating chamber of coatings being done for other telescopes on Maunakea, including UKIRT and IRTF. The coatings being done for the other telescopes are reducing the usable life of the chamber (until it is refurbished). The coatings for the other telescopes are done by CFHT at essentially the cost of the CFHT labor, whereas a more accurate costing might also include facility wear and tear.

RECOMMENDATION #1: Investigate refurbishment of the coating chamber to avoid the possibility of failure in the future.

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SAC was pleased to hear of the excellent progress with commissioning of the new SPIRou instrument so far in semester 18A. The SPIRou team and CFHT staff are to be commended for the unusually few issues encountered in the commissioning of such a complex instrument. Whilst further on-sky tests are required to fully evaluate the instrument performance, particularly the RV stability, SAC is optimistic that technical commissioning can be completed this summer, quickly followed by science verification and then regular science operations, subject to the passing of the formal final acceptance review.

One issue of concern is the lower realized throughput compared to the specifications, particularly at wavelengths below 1.5 microns. The throughput measured in Y and J from observations of stars falls substantially below the expected throughput >10% at all wavelengths. SAC understands this has only a minimal effect on the key SPIRou science goal of RV precision for M dwarfs due to the higher absorption line content of the H and K bands. However, we are of the opinion that improving the blue throughput of the instrument is important to maximize the scientific applications of SPIRou. We therefore recommend further investigation into this issue and pursuit of upgrade options. For example it has been suggested that replacing the rhomboid prisms with new improved AR coatings may be valuable.

RECOMMENDATION #2: To fulfill its potential, we recommend that upgrades to SPIRou be investigated to improve the throughput in the Y and J bands.

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The SPIRou team has informed SAC and CFHT that a Laser Frequency Comb (LFC) for SPIRou has been ordered and is expected to be delivered to CFHT this summer. It is understood that the LFC is under a one year warranty where the manufacturer has responsibility for installation and maintenance meaning that the burden on CFHT effort will be low. CFHT hopes that if the LFC provides improved RV calibration for SPIRou this gain can be experienced by the full user community, despite the procurement rules that prioritize its use by the SPIRou team. In particular, a route to providing community access should be realized as soon as it has been shown that using the LFC provides a clear benefit for certain science applications.

RECOMMENDATION #3: The Laser Frequency Comb for SPIRou should be made available to users of the community whose science would benefit substantially from it, once full capabilities have been realized.

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SAC looks forward to the science verification (SV) of SPIRou and reminds the team and CFHT that SV data is to be made public as soon as practically possible. SAC is pleased to hear the Data Reduction System (DRS) is now in operation for all SPIRou observations and that the DRS developers will be visiting CFHT to integrate it into the CFHT pipeline. It is therefore expected that processed SV data will be available to the community within a week or two after acquisition.


SITELLE’s poor image quality continues to be a major concern for SAC and the detailed investigation of the image quality root cause is a very high priority for CFHT. The camera should be sent to Laval University as soon as possible for the full characterisation with a surface profilometer of all the lenses from center to edge. Downtime should be minimized in order to mitigate any possible impact on future SITELLE observing programs. Users should be informed about the expected improvements once the investigations are complete.

RECOMMENDATION #4: The SITELLE camera should be sent to Laval University for a complete optical characterisation and potential upgrading of its lenses.

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MegaCam is suffering data transfer problems from the instrument to the host computer resulting in corrupted, unusable images. The likely culprit is a faulty fibre optics data link board, called SLINK, interfacing the CCD controller with the host computer. A short-term solution is to fall back to the old dethost computer (adding 3 sec of overhead per image) and replace the faulty SLINK board with a spare one. CFHT is looking into two long-term solutions that do not rely on these SLINK boards, both of which would require significant time to design and implement. SAC recommends that CFHT analyzes these two possible solutions in the coming months.

Some instability during the cooling process and failure of one of the two guiders were also reported. In both cases, root cause was identified and actions are underway to resolve the problems.

The Megacam "quick performance" webpage was updated to display the new, faster 40 sec readout time. This is good, but SAC feels that this information should also appear in the "upgrades" page, where dates pertaining to the changes are also given. In addition, the recent implementation of the shutter timers should also be documented on that page.

RECOMMENDATION #5: Determine a long-term solution to MegaCam SLINK controller issues.

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SAC was pleased to hear that ESPaDOnS and GRACES have continued to operate with few issues. The splotches on the detector and haze on the windows have largely gone/evaporated after extended pumping and application of heat.

ESPaDOnS continued to work well in 17B, with few technical issues and actually benefited from an “overabundance” of nights (i.e. completion of A, B and some C programs). This appears to be due in part to corresponding science programs that are not highly constraining.

GRACES continued to be in high demand with a total of 240hrs requested by the Gemini PIs.

Improved Communication with PIs

SAC was informed that CFHT has introduced new mailing lists with self-service account management and self-signup forms. Throughout the website, CFHT has added invitations to join these lists and to choose which subjects users would like to follow. In addition, when observing proposals are accepted, CFHT plans to automatically add new CFHT users to the email list for the instrument they will be using. SAC is of the opinion that this increased communication with CFHT users is very valuable.

Telescope Use and Scheduling

A detailed report was provided for telescope use in 2017B and 2018A as well as for proposal requests in 2018B. In 2017B the technical loss was reasonably low at 2.8% except for 2 issues affecting 2 runs with SITELLE and MegaCam. Part of the engineering time (~10 hours in total) was taken to start SPIRou commissioning (guiding system). Among DDT proposals (3.4n) part of it is given to high schools (0.6n). SPIRou saw first light on Apr. 24th-25th and had been allocated 2n in March and 6n in April for commissioning with further runs scheduled in May and July. This semester was unusually affected by bad weather causing significant time loss. Regarding proposals received for 2018B, the pressure on ESPaDOnS is still increasing with nearly 400 hours (and mostly from CNRS) and reaches twice the time requested on MegaCam. The pressure for other partners is in the range ~0.8-1.4 all instruments included.

GRACES Time Exchange

Following the high demand of GRACES, Gemini telescope time was offered to the CFHT community. While Canadian and Hawaiian allocations enter through their standard queue mode system, French proposals did not have this possibility. As a consequence, these proposals were sent in classical mode, run by Gemini observatory staff. The completion rate for these have been extremely low, with 2 out of 3 proposals being lost to weather in 17B. SAC was presented a solution to put the French programs in Queue band 1 with an “exchange rate” of 75% (without persistence) or 60% (with persistence, i.e. a program can be persisted from one semester to the next if not fully completed). The French SAC members met and decided to opt for the latter solution: the F programs should be programmed in Queue band 1 with persistence, for an exchange rate of 60% (6hrs obtained for 10hrs allocated).

RECOMMENDATION #6: French programs on Gemini should be placed in Queue band 1 with persistence, for an exchange rate of 60%.

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QSO Report

SAC reviewed the Queued Service observing (QSO) mode for 17B, for the four instruments MegaCam, WIRCam, ESPaDOnS, and SITELLE. Overall, QSO mode is efficient and robust. About 35 hours were gained by using the QSO-SNR mode on MegaCam, and about 50 hours on ESPaDOnS. Time lost to weather was significant in 17B (and worsened in 18A), impacting MegaCam programs the most, and thereby causing low validation rates for the MegaCam LP programs (CFIS and VESTIGE, again, which have been worsening in 18A). ESPaDOnS programs were less impacted and C-ranked ESPaDOnS programs were executed. The Canadian validated/allocated time in total seems high (91%), however about half of this was due to the ESPaDOnS C-programs, which means the validation ratio for Canadian PI AB programs was less than 50%. Presumably this was due to the details in scheduling the programs combined with the poor weather, however the Canadian SAC members are interested in keeping an eye on this.

The SAC received several requests to limit public access to exposure metadata. The motivations included work on high-profile and competitive objects.


The ITAC meeting was not held during the SAC meeting. It will be done by videocon in a couple of weeks.

Large Programs


SAC thanks Jean-Charles Cuillandre and the CFIS team for a most comprehensive biannual report. The new UNIONS collaboration is viewed as a superb initiative. Despite great plans and hopes, weather has dramatically hampered the steady course of this program. CFIS will clearly not achieve its science goals if data acquisition progresses at the present rate. SAC is recommending that CFHT adopts a Completion Policy for Large Programs.


SAC took notice of CIPP’s report and was pleased to see that the program is progressing well overall, albeit with significant time lost to bad weather in the current semester. SAC is also pleased to learn that parallaxes from the team's previous program, which used the same approach, agree well with the GAIA DR2 parallaxes when available.


SAC commiserates with the VESTIGE team about the catastrophic weather statistics in the current semester and acknowledges its impact on the completion rate. SAC is recommending that CFHT adopts a Completion Policy for Large Programs. SAC was pleased to see this did not stop the team from publishing results based on the data already acquired.

Large Program call: 2018B-2022A and LP Completion

The exceptionally bad weather in 2018A has produced a situation where most of the ongoing Large Programs are not expected to achieve final completion levels of 80%. Analysis of the completion of the two MegaCam LPs, CFIS and VESTIGE, shows that together they are already at least 40 nights behind their planned data acquisition rate. A proposal for a LP completion policy was prepared for SAC by Board member J.J. Kavelaars. SAC considered this proposal and agrees on the importance of reaching a minimum completion level for LPs. SAC revised the proposal from Dr Kavelaars and our revised version of a CFHT Large Programs Completion Policy is included in Appendix A of this report. We encourage CFHT and the Board to adopt such a policy and apply it to existing and future Large Programs.

Where the extra time required to complete LPs will come from is a major source of concern. The 400 nights available for new LPs in 2018B-2022A was estimated based on the maximum LP fractions of the agencies. To enable 80% completion of the current LPs during this period would require CFHT to reserve of order 50 nights contingency that would not be awarded to new LPs in the 2018B-2022A call. For future LP calls we recommend that contingency of order 15% of the maximal LP time be reserved to enable completion of ongoing LPs.

Another route to finding time allocation for LP completion is if the Agencies would go beyond their current maximum LP fractions (currently 60% for Canada and 70% for France), potentially just for certain semesters after LPs have suffered due to exceptionally bad weather or technical issues. The final option is for the LP completion time allocations to come from future semesters where no LP time has been allocated; at the present time this would be 2022B onwards.

RECOMMENDATION #7: SAC recommends that CFHT adopts a Completion Policy for Large Programs.

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Large Program proposals for the period 2018B-2022A have been submitted and are currently under review. The evaluations by the National TACs are expected to be ready by 15th June 2018.

The date for the LP TAC meeting will be fixed as soon as all members (3 from Canada, 3 from France, 1 from Hawaii, 3 external) have been designated by the respective institutions. The LP TAC meeting is expected to occur approximately midway between the 15th June and 26th June.

SAC has scheduled a remote meeting on Tuesday 26th June at 8am Hawaiian time, 8 pm French time to review the LP TAC rankings and propose LP allocations to the Board of Directors.

Operational and Development Priorities

  1. Normal operations
  2. SPIRou commissioning, scienc e verification and science operations.
  3. SITELLE optical characterization and improvement
  4. Determining a long term solution to MegaCam SLINK controller issues
  5. New phase 2 system for all instruments and users, followed by queue optimization software.
  6. Mirror coating chamber assessment

2019 CFHT Users’ Meeting

The next CFHT Users’ Meeting will be held in Montréal, and SAC member David Lafrenière will act as the main contact point for its organization. Next year's annual meeting of CASCA will also be held in Montréal and the CFHT Users’ Meeting will be scheduled to immediately follow (or possibly precede) CASCA to maximize and facilitate participation by Canadian astronomers. There will also be an associated SAC meeting. Exact dates will be finalized very soon and a venue is being investigated. It was noted that 2019 marks the 40th anniversary of CFHT and it could be good to plan a few activities to celebrate the occasion.

Next SAC Meeting

The next SAC meeting will take place at CFHT Headquarters in Waimea on Tuesday 20th and Wednesday 21st November 2018, with a telescope visit on Monday 19th.

Appendix A: Draft Completion Policy for Large Programs

The following conditions are true of CFHT’s currently executing and future Large Programs:

  • CFHT Large Programs form a fundamentally key part of the CFHT’s plan to maintain a high level of science productivity;
  • The proposers of such programs design them to achieve a science goal within an expected level of data acquisition;
  • Such science programs are severely hampered by poorer than expected weather and unexpected technical failures that can severely limit data collection;
  • Such Large Programs are often in competition with other facilities or done in concert with those other facilities;
  • Many other facilities have procedures that enable their Large Programs to appeal for extension of their execution phase, to compensate for particular bad weather or technical failures.

Existing and future Large Programs on CFHT may be granted additional time allocation such that the originally planned science goals, on which the LP was awarded time, might be achieved. An LP completion review will be triggered by SAC if, during any of the executing semesters of a given LP the validated exposure rate for that LP fell below 50% of the allocation for an individual semester, or when the entire project will clearly not reach a completeness of 80% of its allocation. The approval of an additional time allocation will be based on a favorable science review of the LP, conducted by a sub-committee made up of representatives from the SAC and national TACs contributing to the specific LP. This sub-committee will work with CFHT to determine the amount and scheduling of the additional time allocation, potentially requesting to the Board a temporary increase in the fraction of agency time allocated to LPs vs PIs.