99th Meeting of the Canada-France-Hawaii Telescope

Scientific Advisory Council

5 - 7 May, 2021 Remotely due to COVID-19

After deliberation during its July 2021 quarterly meeting, the CFHT Board of Directors, in consultation with the Executive Director, endorse the following SAC recommendations:

Recommendation 1 Endorsement of MSE Management Group Suggestion
Recommendation 2 Prioritization of Completion/Deployment of K1 Tool
Recommendation 3 LP Completion Review Sub-Committee Recommendations
Recommendation 4 Consideration of Transit Proposals to Examine Possible Conflicts

The 99th Science Advisory Council meeting was held remotely on May 5–7 2021. SAC members Étienne Artigau, Anthony Boccaletti, Sylvie Cabrit, Emanuele Daddi (chair), Eugene Magnier, Alan McConnachie, Laura Parker (vice chair), Mathias Schultheis, David Tholen and Tracy Webb attended the meeting. The CFHT Executive Director Doug Simons, Director of Engineering Andy Sheinis and Director of Operations Daniel Devost gave presentations and participated in discussions together with several CFHT staff members.

SAC heard from the Executive Director about the ongoing engagement of CFHT with the renewal processes for the master and sub-leases for the Maunakea Observatories. SAC also received updates on the extensive outreach, education and community engagement activities of the Maunakea Observatories, in which CFHT plays a central role. Finally, SAC continues to be impressed with the ability of CFHT and its staff to operate effectively during the difficult circumstances of the past year

SAC was saddened to hear of the passing of Chad Kālepa Baybayan, a Pwo navigator, who served as a navigator-in-residence at the 'Imiloa Astronomy Center of Hawai'i.

SAC thanks Doug Simons for his many years of service to CFHT, and congratulates him on his new appointment as the Director of the Institute for Astronomy at the University of Hawai'i. Doug has played a pivotal role in improving community engagement by the Maunakea Observatories, especially at CFHT. SAC believes that the educational and cultural programs that are now underway, including Maunakea Scholars, Kama'aina Connections, A Hua He Inoa, and others, will be an important and lasting legacy of his tenure as CFHT Director. SAC wishes Doug success in his new role.


SAC thanks Jennifer Marshall and Kei Szeto for their presentations on the current status of MSE. SAC is pleased to see progress being made on the Design Reference Survey and spectrograph design studies, and looks forward to the Preliminary Design Readiness Review in 2022. SAC continues to support the science goals of MSE, and it is clear that MSE is now at a critical juncture in its development. It needs strong support from CFHT to facilitate the timely completion of the preliminary design phase, during which time it will be important to ensure all stakeholders are actively engaged, from the scientific to Agency levels.

RECOMMENDATION #1: SAC endorses the MSE Management Group suggestion of appointing an associate director for MSE or appointing a joint CFHT - MSE director to help lead the MSE during its preliminary design phase and beyond.

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SAC is looking forward to the active engagement of the future director in leading the MSE.


The effort to replace the obsolete and failing MegaCam SLINK boards has essentially completed with the deployment of the replacement GigE boards for operations in December 2020. An additional single-point failure risk lies in the VME WorldFip controller which is no longer available either from vendors or from the second-hand market. Second-hand Linux-based PCI versions of WorldFip are available and CFHT has acquired one through CEA. The Linux driver for this hardware exists, but is not actively developed. Fortunately, CFHT staff have experience with the driver and are in a good position to finish the software work to enable the use of the PCI version. The existing VME version will continue to be used as it remains functional, but this alternative provides insurance against an important single-point failure mode.


SPIRou saw no major problems and is maturing from a phase of development to a phase of operations. Ongoing upgrades were largely targeting sub-optimal performances on a number of fronts. The Rhomb prisms have been changed, leading to a better overall throughput on the blue part of the domain (Y and to a lesser extent J bands). Rhombs are held together by molecular adhesion rather than glueing; this is optically the best solution but can be fragile. The current Rhombs did not separate in more than 6 months of operations. Parts of the front-end are now cooled to minimize the thermal background within part of the K band (>2.15µm). This improvement required new lens mounts to have been purchased that allow for the differential contraction between glass and metal in the cooled parts of the front-end. In the short term, the LFC will only be used within calibration sequences, and not as a simultaneous (C fibre) calibration to science sequences. The main pending SPIRou upgrade is the replacement of the octagonal fiber and slicer upgrade. The provider has been unable to produce the parts to specifications. The SPIRou shutdown to replace the slicer remains tentatively scheduled for 2021B, but recent technical problems regarding procurement suggest that this shutdown will be delayed.

SPIRou+ESPaDOnS co-mount

Reducing the number of instrument changes is a way to decrease operational costs. Although simultaneous observations would be of definite interest, the conclusions from an optics internship were presented suggesting that a dichroic beam splitter would introduce up to 60% loss of polarization signal on the reflected beam (ESPaDOnS). It was thus decided for the moment to prioritize the other option of mounting both instruments on translation stages, to enable quick exchanges on a nightly basis. This would allow, for example, to easily switch to SPIROU for a one-night transit, or conversely to insert a short ESPaDOnS run. The RV calibration would not be affected, as it is determined by the system guiding the target in the fiber entrance, not by absolute telescope pointing. Such a sliding system exists at IRTF, the design could be adapted to CFHT and automated. The nominal operation would be to have night-long swaps and not attempt swapping within nights. This would simplify acquisition software and scheduling and allow for proper RV calibration bracketing of SPIRou observations. The order-of-magnitude effort would be at the 3 +/- 2 FTE level for about one year. SAC is looking forward to the presentation of this concept at the next meeting.

Recoating/shutdown results

The shutdown, originally planned for September 2020, took place in October 2020. The primary mirror was successfully recoated, with the effort taking only 6 of the planned 10 days despite the complexities due to the COVID-19 safety protocols. The resulting coat is reported to be the thickest deposited on the mirror to date, and as a result the system sensitivity has improved significantly. Analysis from MegaCam shows that the zero points have returned to the values measured after the previous recoating in 2017. The newly-installed dry air system for the primary mirror is expected to reduce the future rate of degradation by limiting the water deposits on the primary mirror surface.

Hydraulic system Update

The new hydraulic system is now on site and partially tested. The new system will be fully tested in the coming months and installed while keeping the current system running in parallel. Once the new system is installed the current system will remain as a backup and can also provide spare parts. The final major installation step is to complete the PLC programming that will enable remote control.

Risk assessment and mitigation

Starting in 2020, the engineering group has built a risk register in the form of a shared document (on google doc) that identifies all individual risks of failures on CFHT equipment and instruments, their impact levels on science, personnel, and environment, their likelihood, and the final associated risk. A Risk and Mitigation Working Group has been set up, made up of representatives from all departments of the observatory, that meets monthly to update the Risk Register, develop detailed mitigation strategies, and evaluate their cost and schedule constraints. Many risks were identified (250 items). A prioritized list of the highest risks will be prepared for the next SAC meeting, so as to inform the establishment of contingency funds. SAC congratulates the CFHT engineering staff for this huge effort and concerted approach to avoid major shutdowns in the years to come.

Other technical activities

SAC was updated on several ongoing observatory projects all of which are moving forward at impressive rates. SAC wishes to congratulate the team for successfully juggling so many important initiatives.

The arrival of a new mercury bag continues to hold back the secondary resurfacing, which is now roughly two years past due. SAC learned, however, that a vendor has been identified and contracted.

SAC heard about the Primary Mirror Cosine Regulator, which sets the pressure on the primary mirror supports. The old system was entirely mechanical and suffered reliability issues. Upgrading to an electronic system is expected to increase the reliability and is estimated to take roughly 3 months to implement.

The manufacturing phase of the astrometric camera is almost complete. This new system will increase observing efficiency by roughly 10 minutes per night.

SAC also heard about the integration of the much-awaited Nifty Personnel Lift. Several operational projects have been on hold due to the failure of the older lift, most importantly the servicing of the bridge crane and the fixing of the dome vents. Now, with the new functional lift both of these projects are moving forward and will see progress within the semester.

SAC heard of multiple concerns from CFHT regarding the current Phase 1 Tool, Northstar. The software has become difficult to support and the information needed to plan the upcoming semester is not readily available. This results in excess labor for the staff and scheduling conflicts. CFHT is working on a replacement, K1, to be integrated with Kealahou in late 2021.

RECOMMENDATION #2: CFHT should prioritize completion and deployment of K1, possibly by the end of 2021, since a working proposal handling tool is crucial for the observatory.

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Large Programs


SAC was pleased to see the most recent completion statistics from VESTIGE. The 21A semester has been going well and if upcoming runs are similarly successful then the survey should reach 80% completeness by the end of the semester. If, on the other hand, the upcoming runs do not return substantial validated data then a completeness review would be triggered at the next SAC meeting in November at the latest.


SAC was impressed with the detailed scientific progress report presented by the CFIS team. Unfortunately, while the survey is progressing well, the projected final completion rate will likely fall below the mandated minimum of 80% and thus CFIS will likely require additional nights to be allocated. SAC also learned that surveying the important area of Euclid might not be completed, given the current allocation, having been left to the end of the program. This disproportionately limits their scientific output.


SITELLE has suffered technical issues and shutdowns during past semesters leading to an actual completion rate of SIGNALS of 47%. SIGNALS could achieve in the current baseline scenario a completion rate of 78%. SAC appreciated the report and detailed progress on each galaxy. SAC acknowledges the good publication rate with six papers already being published, but would like to see in the reports additional discussion of high priority science being pursued and specific results obtained.


After the 3 initial semesters plagued with technical and operational issues, the SLS is now ramping up and is reaching a completion rate of 50%, half way through the 21A semester. However, the difficulties encountered at the beginning impact negatively the monitoring with too few RV measurements per target. Overall, with the current efficiency the team anticipates that a completion of 77% will be reached at the end of the survey.

SLS is starting to produce a large number of important scientific results. Meter/s precision is already achievable for some targets owing to improvement in the DRS. Importantly, SPIROU is now demonstrating the interest of near IR RV monitoring which is more resilient with respect to stellar activity, and in some cases allows one to rule out some previously claimed planets. The follow up of TESS and Kepler targets enable complementing radii measurements with mass measurements on planets as small as super earths. At the moment the science goal for magnetic fields observations is met only for very few stars.

The DRS has seen a number of improvements like telluric and sky emission corrections. The RV precision has been improved by moving from the CCF technique to a line by line method. Τhe tool will be made publicly available.

LP completion review

SAC decided to activate an LP completion review for SLS, SIGNALS and CFIS during this meeting, with the LP completion review sub-committee consisting of the whole SAC (including members of the French and Canadian TAC) given that the required actions were considered to be uncontroversial and unanimously agreed upon.

Recommendation #3: The LP completion review sub-committee recommends the allocation of 10 additional nights to SLS, 6 nights to SIGNALS and 32 nights to CFIS. These nights should be scheduled within 21B and 22A, from the LP time available.

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SAC is confident that these extra allocations should guarantee obtaining >80% completion for all the currently active Large Programs by the end of Semester 22A.

Time Allocations

For PI programs the oversubscription factors range from around 3 for NRC and CNRS down to about 0.7 for ASIAA. SPIRou is the most requested instrument, while WIRCam and SITELLE are the least requested. Projects requesting SITELLE have also been proportionally less successful in being allocated time by the various TACs. PI demand for MegaCam is about half what it was five years ago, with a considerable decrease in MegaCam use among high redshift universe programs since the start of CFIS and VESTIGE LPs. In the meanwhile, MegaCam saw a considerable increase in use among solar system programs.


The Queued Service Observing mode (QSO) is continuing to perform extremely well, providing efficient observing well adapted also for time constrained observations. This is thanks to commendable efforts by the QSO team that is still understaffed at the level of three fewer Resident Astronomers than needed. A temporary contract was awarded to alleviate this, and recently extended. All Remote Observers were trained to act as Queue Coordinators. New Resident Astronomers from France are being trained remotely and should join CFHT in the summer.

The global program completion was reasonably high, at the 82% level. This was very high for SPIRou programs (103%) but more modest for MegaCam, SITELLE and WIRCam at the 40-50% level, due mostly to weather and poor sky conditions. Time lost to technical problems was only 1%, similar to the time used by engineering activities. Due to constraints in the scheduling, fewer nights than requested had to be scheduled for WIRCam and ESPaDOnS.

Completion of PI programs was overall high, with inevitable fluctuations among agencies. French programs were most successful (87%, followed by UH at 79%), while Canada was at 55%, connected with a single fairly large SITELLE PI program that could not be scheduled due to observational conflicts with SIGNALS, and also to persisting problems in scheduling PI transits for SPIRou. The average completion of LPs was at 91% this semester, quite satisfactorily on average but with differences among the difference projects: the completion was close to 100% for SLS, VESTIGE and SIGNALS, while CFIS was somewhat lower than 50% due to weather and to the efforts to complete VESTIGE.

Scheduling time-critical observations puts a significant burden on CFHT, and little progress was achieved so far on easing the observability of PI transit projects.

RECOMMENDATION #4: SAC recommends that full consideration of transit proposals require a standardized file that defines the exact time constraints at the time of Phase I (e.g., start/end of window including transit baseline) so that it can be readily merged by the TAC, ITAC and QCs, allowing the examination of possible conflicts.

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GRACES time continues to be requested steadily from the Gemini community, about 7% of their time requests in 21B. This ensures in return a stable flux of 3-4 nights of Gemini time accumulating per semester, to the benefit of CFHT partners. In 21B, 7 nights of Gemini time were offered by CFHT, following the previous 7 nights that were offered in 21A. While UH and Canada are banking this extra time in their Gemini queues, an open call for proposal was issued for the French community. Demand for this France-reserved Gemini time was stronger this semester than in the previous one. SAC expects that all available time should be allocated. SAC anticipates future offering of Gemini time to the CFHT partners through GRACES will happen again a few semesters ahead.

CFHT User's meeting 2022

The next CFHT User’s meeting will be held in France in May 2022, but will also be organized in a format that enables remote participation. We are hopeful that such a hybrid format will allow more people to participate than in previous meetings. Members of SAC along with CFHT staff and local French astronomers will participate in the SOC. The nominal dates for the User’s meeting and adjacent SAC meeting will be May 16 - 20, to be confirmed once all possible conflicts are investigated. SAC members are currently exploring possible host cities.

We note that many decisions including the host venue and hotel need to be made over the summer and confirmed in September. The first call for the conference will ideally go out in November.

SAC will be involved in discussing a theme for the meeting and organizing the scientific sessions and invited speakers.

Operational and Development Priorities

  1. Normal operations
  2. SPIRou, DRS, Upgrade and Kealahou
  3. MSE
  4. K1 Phase 1 tool
  5. Observatory Risk Assessment and Mitigation
  6. ESPaDOnS-SPIRou Co-mount

Next SAC Meeting

The next SAC meeting will take place at the CFHT Headquarters in Waimea (HI) on November 4 & 5, with a tour of the summit organized on November 3, if international conditions permit safe traveling. A remote meeting will be held on the same dates, otherwise.