The 101st Science Advisory Council meeting was held in a hybrid format (Strasbourg and online) from May 11-13 2022. SAC members Stéphane Arnouts (vice-chair), Étienne Artigau, Anthony Boccaletti, Sylvie Cabrit, Eugene Magnier, Alan McConnachie, Laura Parker (chair), Mathias Schultheis, David Tholen and Tracy Webb attended the meeting. The CFHT interim Executive Director Andy Sheinis, interim Director of Engineering Kevin Ho and Director of Operations Daniel Devost gave presentations and participated in discussions together with several CFHT staff members. Jennifer Marshall gave a presentation about the status of MSE. SAC notes that this was our last meeting with Andy Sheinis in the role of interim Executive Director. We would like to thank Andy for his service and for always engaging with SAC in a productive and positive way. SAC also looks forward to working with the incoming Executive Director Jean-Gabriel Cuby. SAC Report, November 2021

100th Meeting of the Canada-France-Hawaii Telescope

Scientific Advisory Council

2 - 5 November, 2021, Virtual

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

Recommendation 1 Executives to emphasize MSE planning, sources of funding and international partnerships
Recommendation 2 Continued funding of MSE Project Office past 2022 including new associate partners
Recommendation 3 High priority on MSE design and development activities
Recommendation 4 VISION pursual including possible contributions from external collaborators
Recommendation 5 MegaCam Exchange Rate
Recommendation 6 New LP call for proposals to begin in 22B

The 100th Science Advisory Council meeting was held remotely on November 2 - 5 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 interim Executive Director Andy Sheinis, interim Director of Engineering Kevin Ho and Director of Operations Daniel Devost gave presentations and participated in discussions together with several CFHT staff members. Andreea Petric gave a presentation about the status of MSE.


The MSE Project Office presented updates of their ongoing scientific and technical studies. This includes improvements to the Exposure Time Calculators used by the science teams, and ongoing scientific trade studies relating to the performance and specifications of the medium and high resolution spectrographs. This work has occurred in tandem with significant redesigns of the medium and high resolution spectrograph systems, and SAC is pleased to see the designs advancing towards new review milestones. In addition, SAC heard of new studies examining the effects of ghosting from the wide field corrector, and is pleased to see the engagement of other CFHT staff in these important studies.

SAC welcomes new statements by MSE on both the Cultural Heritage of Maunakea and on Equity, Diversity and Inclusion.

SAC also heard from Andy Sheinis and the MSE Project Office on new initiatives for engagement of partners and identification of suitable funding pathways for MSE. SAC is pleased to see the active role the Interim Executive Director is taking in creating new opportunities for MSE, and SAC looks forward to seeing these initiatives continue and grow.

SAC was very concerned to hear of the impending funding issues relating to core Project Office activities, especially since the new initiatives discussed above are unlikely to provide support on the necessary timelines. SAC reiterates their support of MSE, and the related need for a fully funded Project Office.

MSE remains the future vision for CFHT and is well matched to the need for massively multiplexed optical spectroscopy identified in the Astro2020 process. This is a critical time to step-up the work in view of possible new funding opportunities, and of the anticipated Master Lease renewal.

RECOMMENDATION #1:SAC encourages the continuation of an active role from the Executives in planning for and seeking new sources of funding, pursuing agency engagement, and expanding the international partnership for MSE.

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RECOMMENDATION #2:SAC emphasises that continued funding for the core MSE Project Office is necessary for the successful development of MSE, and sources need to be identified beyond the currently funded period ending in 2022, including from new associated partners for CFHT.

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RECOMMENDATION #3: Essential design and development activities for MSE should be the highest priority development project for CFHT, and resourced accordingly.

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ESPaDOnS/SPIRou Co-mount

The Spirou/ESPADONS co-mounting project has significantly evolved since the summer with a new solution (named “VISION”) proposed by the French IRAP/OMP team which could ultimately allow simultaneous observations with these 2 instruments. The concerns with a prior alternative solution (“Spiroudons”), involving a sliding mechanism, resided in the induced loss of polarimetric efficiency and crosstalk, which prevented simultaneous observations, and more importantly the risk of degrading the RV stability of Spirou. The new design has smaller incidence angles to preserve polarimetric capabilities in the 2 instruments, and the moving parts are reduced to small components (dichroics or mirrors) in the Cassegrain unit. The concept is also beneficial for operations and scheduling (in particular for allowing transit observations), and for improving monitoring coverage for both instruments

The two standalone modes (either Spirou or Espadons alone) are relatively straightforward to implement and are regarded by CFHT as a more robust solution than Spiroudons, although the impact of the changing gravity environment on ESPaDOnS needs to be taken into account. If feasibility is confirmed, CFHT expects that the study can in principle start in March 2022 and could require 1.5 years of work with an investment of order of 3 FTE. The simultaneous mode remains to be studied in more detail since it involves a set of 3 specific dichroics but can be conceived as a goal for a second phase of the project provided resources are available. In all these efforts, CFHT could rely on the IRAP expertise (and possibly resources) to support the analysis and implementation of the three modes. SAC recognises that on these timescales CFHT might be undergoing changes that make it unclear, at this point, if the VISION project would provide sufficient return on the investment.

A science cases document for the simultaneous mode has been provided by the community highlighting the power of combining high spectral resolution at visible and near IR for exoplanetary science. If obtained simultaneously (or close in time) the dataset will provide a significant improvement for distinguishing a planet’s signal from stellar noise due to chromospheric activity or stellar spots. Such an instrument could also be used to characterize transiting planets, by detecting atomic and molecular lines probing different pressure levels in a planet’s atmosphere. SAC recognises the high quality of the science case and the strong potential scientific impact of the simultaneous observing mode.

RECOMMENDATION #4: SAC sees potential in VISION and recommends it be pursued, to the extent that it does not impact higher priority tasks, especially MSE. We encourage CFHT to explore the possibility of direct contributions from external collaborators who may have access to the necessary resources and expertise (in particular with IRAP/OMP).

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The Kealahou team has made good progress on improvements to K2, the Kealahou Phase 2 Tool, implementing a number of advanced scheduling features, including moving target options, while maintaining support for the operations of SPIRou under Kealahou. The effort to migrate ESPaDOnS to Kealahou K2 is nearly complete. The Kealahou team are now turning their attention to the K1 portions of Kealahou with an anticipated release of August 2022 in time for 23A, at which point NorthStar can be dropped.


SPIRou will be warmed and opened for maintenance to perform a number of improvements. These include the addition of an LED on the optical bench that allows the illumination of the array without going through the fibers and dispersive optics. The LED will permit better characterisation of the persistence. Flash-flooding of the array with the LED may allow removal of the persistence after the observation of bright stars. Also, fibers will be thermally anchored at their entry point in the cryostat to increase the thermal stability of the optical bench. Finally, the slicer will be upgraded. These changes may await the end of the SLS as it will create an inevitable glitch in the pRV time series, barring evidence for more urgent interventions. Upgrades within the Cassegrain unit (stabilization and cooling to minimize background) are also planned.


MegaCam has currently only one known remaining risk of failure due to the WorldFip interface: the instrument controller that communicates with the camera. The old VME hardware has become obsolete and although a new, equivalent, PCI card has been installed the software is still under development. It was reported that the software is now ~80% complete and the team anticipates it will be completed by early 2022

f/8 recoating

The f/8 secondary was successfully recoated in September. The secondary is typically recoated every five years but this process was delayed by two additional years due to COVID and the challenge of procuring a new mercury bag. The updated aluminizing chamber led to significant improvements in the recoating and resulted in a 55% increase in coating thickness. This improved thickness has led to better throughput for both SPIRou and SITELLE. SAC commends CFHT for this success

Hydraulics update

The hydraulic system was delivered in July 2020 and the transfer to this new system will happen by the end of the year after some finishing work on the GUI. Having this new system, with built-in redundancy, is a major accomplishment for the observatory and will retire a significant risk. The old system will remain in place for some time as a back-up.

Dome vents

The arrival of the new Nifty Lift allows the staff to access the dome vents. Inspection showed that 8 of the 12 vents could be used. For now, operation is limited to 2/3 of the full range, but they can be used as long as the weather permits. Water accumulation and freezing continues to be a concern, so further engineering work will be needed before the vents are fully operational.

Network issues

Two major network-related problems occurred and were addressed by the staff. In the first case, spurious or excess broadcast traffic on the summit network interfered with the operation of older equipment. Changes to the switch to block this variety of broadcast packet resolved the situation. In the second case, a security breach at CADC necessitated a change of the data transfer system between CFHT and CADC. A cooperative development process resulted in a more secure and more reliable replacement system. SAC commends the staff for quickly and effectively responding to these two difficulties.

Other technical activities

Some long running projects appear close to completion. The astrometric camera mounting bracket has been fabricated and deployment of the full system on the telescope is imminent. Effort on the cosine regulator project, which has been blocked by the astrometric camera, will then be resumed with completion planned in the Spring.

Time Allocations

For semester 21B, Spirou was the most frequently scheduled instrument, with just under 50 percent of the total allocation. MegaCam was a distant second, with just under 24 percent. ESPaDOnS and SITELLE were scheduled for 12 percent and 10 percent of the nights, respectively, with WIRCam being the least utilized instrument this semester at about 5 percent. However, instrument priority varies among the partners, with Spirou being the most frequently requested instrument by Canada and France, while UH uses the majority of its time with MegaCam, and NAOC+ASIAA utilizing WIRCam more than any other instrument. Among large programs, Spirou represents two-thirds of the allocated time, with the remaining third almost equally split between MegaCam and SITELLE. In 21A, only 1.4 percent of the observing time was lost to technical issues. Approximately 0.2 nights were used by high school students via the Hawaii Scholars program.


The QSO chain of operation is efficient and robust and is well adapted for time constrained programs. For 21A, MegaCam had 79 nights of allocation, WIRCam 15 nights, ESPaDOnS 13 nights, SITELLE 9 nights and SPIROU 54 nights. The completion of the A programs was high for MegaCam, WIRCam and SPIROU (>95%) but low for SITELLE with only 37% due to bad weather. MegaCam, WIRCam, ESPaDOnS and SPIROU lost less than 25% of the available time due to bad weather which is extremely good and only a very small amount of time due to technical issues. On the other hand, SITELLE was unlucky with the weather and lost nearly 65% of the available time. The SLS program took advantage of the excellent weather conditions in 21A, obtaining 15-20 hours of observations more than what requested. Canada had 5 distinct programs on MegaCam but some of them were asking the same conditions and RA ranges than the CFIS large program and could not be observed, similarly to one PI program from France. The PI agencies UH, NAOC and ASIAA performed very well.


SAC heard an update on GRACES and is pleased that it continues to be requested by the Gemini community. SAC also heard that a new Memorandum of Understanding is being discussed between Gemini and CFHT, and looks forward to a new agreement being signed. SAC notes that the previous agreement especially benefited the CFHT User Community by providing access to a northern 8m telescope, especially one equipped with high resolution spectroscopic capabilities.

Megacam exchange rate

For several semesters, evidence has been mounting that the time exchange rate of 5.5 h/night for Megacam might have been overestimated. SAC was presented with observing statistics going back several years concerning the number of Megacam hours of science on-sky time per night. The exchange rate is based on A+B+C+S observations (and is similarly calculated for other instruments) and for Megacam this is now found to be closer to 5 hours/night. It is crucial that proposers have accurate exchange rate numbers when designing observing programs.

RECOMMENDATION #5:The exchange rate for Megacam shall be 5.0 hours/night, starting from semester 22B when new LPs will start, and will apply to all programs and agencies.

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Large Programs:


CFIS has made a significant leap forward in 21A, thanks to good weather conditions and optimal scheduling by the CFHT QSO team. The overall completion rate is now 75.8%, and will reach above 80% by the end of the LP if progress continues at the same pace (with 32 extra nights allocated during the last SAC LP completion review). The Northern portion of Euclid DR1 (1/3 of the total DR1) is now covered at 50%, and will be completed at high priority in 21B and 22A. A large number of science projects are already in progress, with 12 papers published and 5 submitted, as well as a large effort to build a consistent ugriz catalog over several hundred square degrees using complementary data from other telescopes.


The SIGNALS large program is progressing well with a completion rate of 54.6%. While the semester 21A suffered bad weather conditions, 21B had no issues and the expectation is that at the end of 22A SIGNALS could achieve a completion rate above 80%. So far, 8 papers have been published and the SIGNALS team made efforts in improving their data reduction software and data analysis (e.g using machine learning techniques).


The SLS large program has now reached maturity from the point of view of the data analysis and scientific output. The validation rate is already of order 80% and with the extra 10 nights allocated previously, SAC expects that this LP will finish in 22A. This semester 21B, thanks to the very large time allocation, conditions were ideal for monitoring. SAC regrets that monitoring was unsatisfactory in the first few semesters. This was in part connected to the poor early validation rates and time losses. The subsequent improvement in monitoring rates was also largely due to SAC recommendations that have already attempted to favour the SLS, while affecting SPIRou PI transit program scheduling and the overall scheduling of observatory runs.

LP call for proposals

RECOMMENDATION #6:SAC recommends proceeding with the implementation of recommendation #1 of its September 2021 telecon report, enabling a new round of Large Programs to start in semester 22B, for a duration of 4 semesters (2 years). The amount of time offered shall be 300 nights from the C and F agencies, plus any agency or other partner contribution, offering all five CFHT instruments. At least an additional 40 nights of LP time are kept in reserve for implementation of the completion policy for the new LPs (and possibly for the current LPs, if needed).

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The approximate timeline for the selection process would be the following:

  • Jan 15, 2022: Large Program call opening
  • Feb 15, 2022: Required but non-binding letters of intent due
  • Mar 31, 2022: Large Program proposal deadline
  • May 1, 2022: LP ranking by national TACs
  • May 21, 2022: LP TAC meeting
  • June 1, 2022: SAC telecon for LP selection
  • Late June 2022: BoD time allocation

The implementation procedures will be soon available on the CFHT web site.

CFHT User's meetings 2022

The User’s Meeting is confirmed for the week of May 9th in Strasbourg. The SAC meeting will take place adjacent to the User’s meeting. For the first time, the User’s Meeting will be hybrid in format and the LOC has been meeting regularly to finalize the venue (hotel versus observatory) and discuss the technical requirements for a hybrid meeting. In addition, CFHT will soon survey the user community to gauge the interest in attending in person versus remotely. The SOC will have a meeting soon to discuss the science themes and topics and to identify invited speakers.

Operational and development Priorities:

  1. Normal operations
  2. K1
  3. MSE
  4. SPIRou upgrade and DRS support
  6. Dome vents

Next SAC Meeting

The next SAC meeting will take place May 9-13th, 2022 in Strasbourg (France), if international conditions permit safe traveling, and will be hosted by the Observatory of Strasbourg. A remote meeting will be held on the same dates, otherwise.