103rd Meeting of the Canada-France-Hawaii Telescope

Scientific Advisory Council

23-25 May, 2023, held remotely

After deliberation during its Quarterly Report-II 2023 teleconference, the CFHT Board of Directors, in consultation with the Executive Director, endorse the following SAC recommendations:

Recommendation 1 Support for Implementing VISION
Recommendation 2 Decommissioning Instruments - One Dark Time and One Bright Time Instrument in the Future
Recommendation 3 Develop Science Case for Wide-Format IFU
Recommendation 4 Explore Funding for Wide Format IFU
Recommendation 5 Community Consultation
Recommendation 6 Switching between ESPaDoNS, SPIRou, and Future IFU Within One Night
Recommendation 7 VISION Integration a Top Priority/Pipeline Maintenance
Recommendation 8 LP vs PI Publications Comparison

Report of the 103rd meeting of the CFHT Scientific Advisory Council, May 2023

The 103rd Science Advisory Council meeting was held remotely from May 23-25 2023. SAC members Stéphane Arnouts (vice-chair), Étienne Artigau, Isabelle Boisse, Ken Chambers, Ting Li, Philippe Mathias, Alan McConnachie, Laura Parker (chair), Mathias Schultheis, and David Tholen attended the meeting. The CFHT Executive Director Jean-Gabriel Cuby, Director of Maunakea Spectroscopic Explorer Programs Andy Sheinis, Astronomy Group Manager Nadine Manset, Director of Science Operations Daniel Devost, and Gregory Barrick gave presentations and participated in discussions together with other CFHT staff members. SAC appreciated having so many staff present during the open sessions who could describe ongoing work and answer our questions.

SAC would especially like to acknowledge and thank Daniel Devost for his many years of service as the Director of Science Operations. We have enjoyed working closely with Daniel on many operations issues and look forward to working with Nadine Manset when she takes over this role later this year.

Community Engagement

SAC commends the observatory for its ongoing and sustained commitment to community engagement. In particular SAC thanks Mary Beth Laychak for her report updating us on the many activities in which CFHT is engaged. In addition, we support the plan to provide resources to CFHT users so they can acknowledge Maunakea when presenting their CFHT-related results. SAC further supports the creation of a DEI committee and their plans to strengthen links with the local community.

As noted in the Executive Director’s report, any possibility for a future of CFHT as MSE rests in doing things differently; in engaging the local community in authentic and meaningful ways. SAC looks forward to meeting in person in Waimea in late 2023 and would happily participate in a community engagement event.

Future of CFHT

At our November 2022 meeting SAC endorsed the observatory’s plan for the next decade, with an instrumentation suite including VISION (co-mount of ESPaDOnS and SPIRou), a wide-format IFU, and a multi-object spectroscopic survey instrument. This plan will ensure scientifically interesting capabilities for CFHT while planning for a future with MSE. Since that time there has been a call for letters of interest in collaborating on MSE and the MSE Pathfinder Project (see further discussion in next section). In addition, there was an unsuccessful NSF MSRI proposal and there are two pending NSF proposals (MRI and ATI).

The plan presented at this meeting remains much the same: to operate CFHT for another ~10 years with some operational and instrumentation updates, develop the Pathfinder as resources allow, and transition to MSE eventually. With the change in the management structure of Maunakea and the delays to any possible new projects, the CFHT Board sees this as a critical time to do further consultation to understand what the CFHT user community wants in the coming years. They have asked the SAC to help in this consultation (see further comments below). In addition, it is worth noting that Canada is about to undertake a major review of all optical and near-IR ground-based facilities they have access to or could have access to. The resulting report from this review is due in 2024. At the same time the next French “Prospective“ exercise will also soon be launched. In order to contribute to these processes the CFHT consultation should complete by the end of 2023 and ideally be part of SAC discussion at our next meeting.

It is clear that CFHT is operating within a constrained-budget environment. The short-term plan needs to work within the current budget while providing a scientifically exciting near-term to keep all partners engaged. SAC discussed at length what the next five years at CFHT could look like. We note that there are two instruments that are much less in demand and that reducing the number of instruments has a number of advantages: slight operation savings, easier to schedule, in particular LPs that benefit from having the same instrument on the telescope for extended periods, and it is easier to respond to ToOs if the most popular ToO instruments are available. This combination of operational and scientific advantages lead SAC to recommend considering retiring WIRCAM and SITELLE in the near future, while giving communities advance notice and time to plan. In particular we suggest phasing out access to WIRCAM on the timescale of the end of the current associate partnerships (by ~2025). One instrument exchange between dark and bright time, alternating between MegaCam (dark time) and the co-mount of SPIRou, ESPaDOnS and an IFU within VISION (bright time) would minimize the complexity of daytime operations at the summit. One bright time (as a co-mount of multiple instruments) and one dark time instrument also may allow for more ambitious individual LPs. SAC acknowledges the unique and powerful capabilities of SITELLE and there may be other observatories interested in hosting this instrument.

RECOMMENDATION #1: SAC reaffirms its support for implementing VISION, the co-mount of ESPaDOns and SPIRou, as soon as possible, while making sure that a future integration of a wide-format IFU remains possible.

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MSE (and Pathfinder)

SAC heard a report from Director of Maunakea Spectroscopic Explorer Programs Andy Sheinis. SAC is pleased that Peter Frinchaboy is the new MSE Project Scientist and looks forward to working with Peter at future SAC meetings in his new role. Given the new timeline that has become apparent for MSE, SAC appreciates that near-term MSE activities should focus on partnership building and developing spectroscopic initiatives at CFHT. In this respect the Pathfinder activities take on particular importance, and its potential for tying the near-term future of CFHT into the long-term future of MSE, including for its current and potentially new user communities.

As discussed, SAC is especially excited about the potential of a renewed instrument suite at CFHT in the near term that includes MegaCam as the sole dark time instrument, and that includes VISION - with SPIROU and ESPaDOnS, and incorporating the wide-format IFU from the Pathfinder - as the bright time suite (with easy interchange of bright-time instruments during the night). In this way, SAC believes CFHT can present a compelling unified science vision, and stresses that their excitement for the Pathfinder IFU is as a result of what the integrated suite of capabilities will enable, not just the science provided solely by the IFU. Once an IFU is deployed, possible development of a MOS capability to feed the same spectrograph becomes more feasible and is a scientifically compelling possibility.

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RECOMMENDATION #2: SAC recommends decommissioning instruments in the near future to focus on one dark time instrument (MegaCam) and one bright time instrument package (VISION co-mount of ESPaDOnS and SPIRou plus a wide-format IFU) in the coming ~5 years. This instrument suite represents a scientifically compelling combination well suited to future LPs and rapid response to targets of opportunity.

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RECOMMENDATION #3: SAC recommends that the MSE Project Scientist, Pathfinder Science Team, in consultation with CFHT stakeholder communities, develop the science case and design characteristics for a wide-format IFU that when combined with MegaCam and VISION can help link the near-term future of CFHT to the long-term vision of MSE.

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In parallel with this initiative, SAC agrees with the Executive and MSE Director that MSE should focus on becoming a model for community-wide engagement and development, and encourages CFHT to continue to amplify their activities in this direction. On the technical side, it must be recognized that the limited financial resources available mean that development should focus on those areas that best emphasize the scientific utility of the facility in a continually changing landscape, with the benefit that this development can be used by international audiences to engage their respective scientific communities and funding organizations. In this respect, the SAC congratulates the MSE Director on the initial engagement of potential partner communities and possible funding agencies, and looks forward to seeing this level of engagement grow.

RECOMMENDATION #4: SAC recommends that the Executive prioritize exploring all possible routes for funding the wide-format IFU, including national funding agencies, philanthropic donations, and in-kind contributions, as the first step in enabling the full Pathfinder instrument, and ultimately MSE.

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Community Consultation

SAC discussed the best way to engage and consult the community on the future of CFHT. This consultation is particularly timely as the Canadian community will soon discuss their engagement in various ground-based observatories, and the French community will do its 5-yr prospective next year.

SAC does not feel that a Users’ Meeting so soon after the last one is the best way to carry out this consultation. We do note that the future of CFHT should be a more substantial component of the next Users’ Meeting.

We propose that a survey could be sent to the community. In order to be efficient and most useful, the questions should be quite targeted. We propose presenting a small number of possible models for the future of CFHT and ask the user community to provide yes/no or rankings of these options. Although there is power in an anonymous survey SAC recommends encouraging respondents to identify themselves so we can understand the relative priorities of different member communities and also to track whether we are getting feedback from a broad user base.

In order to optimize the utility of the survey it is important that respondents have the background knowledge and context to be able to understand the possibilities. To help with this SAC suggests creating a background document and hosting a webinar in advance of the survey being released. The purpose of the webinar will be to present the different options described in the survey and also to provide an opportunity for users to ask questions.

SAC discussed the various options (instrument suite, LP options, Pathfinder options) that could be proposed to the community and is happy to discuss these in detail with the Board and Executive, but recommends a focused survey with a small number of options.

RECOMMENDATION #5: SAC supports the Board’s plan to engage in community consultation regarding the near-term future of CFHT. We recommend a focused survey with a background document and webinar to provide information so users can understand the options.

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We received an update on the response to the request for a formal collaboration with IRAP. A funding proposal was submitted and feedback should be received very soon. The experience from the SPIP/NARVAL co-mounting will be key in developing VISION. It was noted that SPIP has a major detector issue that may require shipping its science array to Teledyne. This should not directly impact VISION but may affect staff availability at IRAP.

Exchange within a single night between any of the 2 or 3 spectrographs would be a significant advantage. It would extend the capability to obtain spectroscopic ToO to bright time with the IFU.

The observatory is in good position for mode 1 and 2 to be included in Kealahou by Q2 2024 and of mode 3 in the second half of 2024.

It was noted that the proper calibration of each spectrograph in VISION may be non-trivial and outside the current calibration scheme. This is linked to both the challenge of including dual calibrations in Kealahou and differences that may arise in maintaining m/s pRV performances.

Peripheral to the co-mounting, ongoing work is being done on SPIRou to improve the thermal background of the instrument from the cassegrain unit.

RECOMMENDATION #6: SAC recommends making the possibility to change between, ESPaDoNS, SPIRou, and a future wide-format IFU within a night an operations requirement.

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SAC congratulates the Kealahou team for the ongoing successful development efforts on the new proposal review tool (PRT) and the migration of the Sybase database on a virtual machine to improve performance. The PRT, with more functionalities and upgradability, replaces NorthStar and was successfully used by the French TAC during its evaluation process and should be envisioned for other agencies.

The observatory proposed changing the priority for the deployment of the instruments on the Kealahou 2 platform. The migration of MegaCam is considered more urgent than SITELLE. A rapid ToO capability (see later section) is now planned on K2. This new observing mode is expected to be used primarily with MegaCam. SAC supports the plan to transition MegaCam before SITELLE with an expected availability at the end of 2024.

The Kealahou team will develop the VISION integration for mode 1 and 2 in parallel with the MegaCam effort but do not anticipate any conflict, with an expected delivery at the end of 2024. Mode 3 should follow six months later. SAC encourages the Kealahou and VISION teams to closely interact for a seamless development effort.

Science-Operations Review

SAC applauds the observatory for undertaking a thorough review of operations activities and identifying possible efficiencies. The observatory presented a list of recommended priorities as follows:

  1. Implementatoin of a rapid ToO capability
  2. VISION integration and software development
  3. Development of semi-autonomous exposure grading and validation system
  4. Development of a new computer assisted queue preparation tool
  5. Kealahou K1 and K2 development
  6. Pipeline maintenance and development

SAC is generally supportive of the order suggested but had a few comments to share. First, placing pipelines at the bottom of this list concerns us. The science utilization of CFHT data requires working pipelines, and a low level of activity to maintain and keep things working is critical. There may not be the capacity to build new pipelines within CFHT but maintenance needs to be a high priority. We appreciate the observatory's preference to outsource pipeline development but it is important to have a model where the external partner has an incentive to continue to maintain the pipeline (small ongoing contract for example).

Our second main concern is placing a rToO capability as the top priority. We strongly encourage developing this new and timely capability, and we recognize that much of this effort is to integrate MegaCam into Kealahou. However, for the ranking we recommend keeping VISION as the top priority. We also note that VISION can also take advantage of the new ToO framework.

As a final note on this list, SAC was happy to see that there are planned efforts to make data grading and validation more streamlined. In the near future there will hopefully be data from multiple instruments taken in a single night (VISION) and grading these data will be challenging. A more efficient system will be particularly important going forward.

RECOMMENDATION #7: SAC endorses the list of recommended priorities but places VISION integration at the top of the list and recommends that pipeline maintenance at a low level remains a required activity.

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Operations Updates

Data were provided showing the MegaCam zero points have been remarkably stable over the 10 months since the primary mirror was recoated. This is attributed to the improved mirror coating procedure and the implementation of a dry air system under the mirror covers to decrease the humidity the mirror is exposed to when not observing. This is very good news and SAC commends the team for these important developments.

SAC notes the end of the Gemini Remote Access to the CFHT ESPaDOnS Spectrograph (GRACES) program. It was very successful, but neither partner has shown strong interest in continuing this program.

SAC supports both the decision to operate the dome vents at ⅔ the normal open position as this has a very small effect on observing and prevents the trapping of water that does cause problems and the plan to retrofit and test one vent. In the ongoing efforts to understand changes in seeing at the observatory it would be useful to have a quantitative analysis of the impact of dome vent opening fraction on seeing.

The preparations for updating the cosine regulator for the primary mirror support system seem well in hand. SAC encourages the effort to reduce the draw on the already stressed dry air system.

SAC notes and commends the staff on the updated electrical system for the computer room. In addition SAC was pleased to hear of the substantial efforts to increase network security and collaboration and endorses efforts to work with the other observatories to improve network security on the summit.

SAC applauds the staff on the many efforts to improve fluid containment features. SAC notes that other observatories (Pan-STARRS, IRTF) have switched to food quality glycol for a coolant that has very nearly equivalent cooling properties and mitigates the risk of any glycol spill.

Large Programs

The current round of LPs are now almost one year into their two year duration. Like all programs at CFHT they have been affected by the terrible weather on Maunakea in recent months.


UNIONS integrates the past CFHT LP LUAU and CFIS; it is a joint effort with the Pan-STARRS, WISHES and WHIGS teams. The UNIONS completion rate lags behind the required original allocation since it is a heavy A semester target and weather is heavily biased to be poor in A semester. It is unlikely to be finished in the next 2 semesters and may need a 3rd A semester to complete the survey.

SAC emphasizes that UNIONS has a large legacy value in the LSST and Euclid era due to its northern sky coverage, u-band sensitivity and image quality (1yr LSST depth); SAC also congratulates the UNIONS team for many significant science outcomes (and CFIS, its predecessor) with 15 publications submitted or published in 2022 and 2023 so far.


CLASSY is a new LP with MegaCam to survey the outer solar system. It had a very successful run in the first semester in 2022B; however, in 2023A they have been severely affected by poor weather and their completion rate has suffered. Since CLASSY also uses MegaCam, it directly competes with UNIONS, making it even harder to schedule in the A semester. Since CLASSY has a lower TAC ranking than UNIONS, it also has lower priority than UNIONS.


SPICE is a new LP for 2022B with SPIRou, aimed at detecting and characterizing Earth-like exoplanets around nearby M dwarfs. With a 26% completion, it is a bit behind schedule, but should be able to complete if weather is cooperative in the coming semesters.

The SPICE team notes that the monitoring rate is not at the level they would like it to be. The reasons for this are multiple but the observatory notes that it is hard to schedule since 1) the scheduling directly competes with MegaCam runs, 2) SPIRou is in high demand, and 3) many targets are pushing the declination limit. Future VISION 1&2 mode will help and improve the monitoring rate. QSO also suggests that SPICE should give priority on their targets.

SAC continues to support the 2019 recommendation that the QSO team should make efforts to ensure that the ratio of validated to allocated time for Large Programs is at least equal to that of all PI programs.

Given the extremely poor weather in recent months there is a very real possibility that the current round of LPs will not complete within the planned two-year window. SAC will revisit the completion statistics at our next meeting but wants to signal that we recommend extending the LPs if needed, given the compelling science of these programs, and in the case of UNIONS the need to contribute data from particular areas to a multi-observatory international effort.

Furthermore, LPs remain an integral and high impact part of CFHT operations. SAC sees compelling cases for future LPs for both VISION and MegaCam (in particular the u-band capability). As the future of CFHT is discussed in the coming months SAC notes their continued support of using a large fraction of CFHT time to support LPs.

Before the current round of LPs finish and a possible next call is developed it would be useful to understand the impact of LPs at CFHT versus PI programs.

RECOMMENDATION #8: SAC recommends collecting publication information to compare the number and impact of LP and PI programs (per night of observing time).

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Time Allocation Report

There were significant weather losses in 2022B continuing into semester 2023A. The November 27 to December 12 eruption of Mauna Loa also caused a loss of a little more than 55 hours of observing time due to concerns over volcanic dust. Technical losses amounted to just 2.11 percent. The instrument schedule was adjusted to account for weather losses that occurred early in the semester.

PI proposals in semester 2023A received, in descending order of allocated time, Megacam (33 percent), ESPaDOnS (19 percent), SPIRou (14 percent), WIRCam (9 percent), and SITELLE (6 percent), but instrument time allocation priorities continue to vary from partner to partner. For 2023B, the PI instrument demand order is ESPaDOnS, SPIRou, SITELLE, MegaCam, and WIRCam, however the actual time allocations per instrument may not reflect the demand depending on the ITAC rankings. Note that neither Canada nor France requested WIRCam in 2023B. Two of the three large programs utilize MegaCam while the other utilizes SPIRou.

Telescope time oversubscription continues to be around 2 for NRC, CNRS, and ASIAA, while closer to 1 for UH and NAOC.

Although Gemini did not renew the MOU to operate GRACES, there is some time remaining in the exchange program that will need to be used by semester 2024A.


QSO continues to be an effective and efficient observing mode for all 5 instruments and is well adapted for time-constrained programs.

In the 22B semester, time lost due to weather was 27% while very little was lost to technical problems (~1%). Global completion for PI programs is above 80% and 99% for the LPs. ESPaDOnS and SPIRou were more impacted by the bad weather and by the Mauna Loa eruption (56h lost, during a SPIRou run). As a consequence, the program completion for the French and Canadian agencies, the main users of these instruments, is low (65 and 53% resp.), while it is above 78% for the other agencies. Due to the SPIRou repairs, the special call for MegaCam with 5 nights led to the observations of 5 PI programs, with a final completion above 80%. We note that high completion rates are particularly challenging for monitoring programs in a semester with bad weather.

In the ongoing 23A semester, bad weather continued with more than 50% of time lost. This will definitely impact the completion of the PI programs and the progress of the LPs, ending in 24A. The QSO team will have to manage the work overload during the replacement period of two Resident Astronomers.

Seeing Analysis

SAC thanks the observatory for ongoing efforts to study the evolution of the seeing on Maunakea. DIMM data, taken close to zenith, shows no or very mild evolution over the last five years, contrasting with the evolution observed on the MegaCam images. A coeval (time matching) comparison between DIMM and MegaCam measurements confirms that the increasing trend seen in MegaCam is more pronounced than the one from the DIMM, and both appear to have returned to nominal values in the last three semesters. While complex phenomena may be involved in the seeing measurements in MegaCam images, SAC encourages the observatory to pursue this investigation and to include seeing corrected-to-zenith for the MegaCam images. SAC also encourages the observatory to communicate with other observatories (e.g. Subaru) to check if similar trends are observed over time.

Operational and Development Priorities

  1. Normal Operations
  3. Wide-format IFU development
  4. Kealahou

Next SAC Meeting

The next SAC meeting will be in late fall 2023 in-person, in Waimea. Our preference to enable as much in-person participation as possible is the week of December 4th.