Canada France Hawaii Telescope
98th Meeting of the Canada-France-Hawaii Telescope
Scientific Advisory Council
4 - 6 November, 2020 Remotely due to COVID-19
After deliberation during its November 2020 quarterly meeting, the CFHT Board of Directors, in consultation with the Executive Director, endorse the following SAC recommendations:
| Recommendation 1 | Request for SPIRou report on Upgrade benefits and risk analysis |
| Recommendation 2 | Prioritizing of SPIRou/ESPaDOnS co-mounting option |
| Recommendation 3 | Dynamic scheduling tool for transits and RV monitoring |
| Recommendation 4 | Flagging conflicting transit programs ahead of TAC and ITAC meetings |
The 98th Science Advisory Council meeting was held remotely on November 4 - 6 2020. SAC members Anthony Boccaletti, Sylvie Cabrit, Stéphane Courteau, Emanuele Daddi (chair), David Lafrenière (vice-chair), Eugene Magnier, Nicolas Martin, Roberto Mendez, Laura Parker, and Tracy Webb attended the meeting. The CFHT Executive Director Doug Simons, Director of Engineering Andy Sheinis and Director of (Science) Operations Daniel Devost gave presentations and participated in discussions together with several CFHT staff members. Jennifer Marshall, Kei Szeto and Alan McConnachie provided updates on MSE.
Following the CFHT Executive Director’s report, SAC joins in commending the tremendous achievements by the observatory staff during the difficult times of the COVID-19 pandemic.
SITELLE:
SAC was pleased to hear that issues with the image quality across the field and the anomalous alpha particle ray counts in the instrument have been resolved. SAC applauds CFHT for installing a new set of field lenses made with the highest purity fused silica. Thanks to this implementation, the image quality of the instrument now meets the expected specifications.
MegaCam:
The main development effort for MegaCam is the design of a new set of data transfer cards to replace the aging SLINK system. While still operational, SLINK is old technology and CFHT has limited spare boards. SAC heard about the new GigE system that will replace the SLINKs and support MegaCam for future operations. The new noise pickup issue has been resolved through effective isolation of the boards. This upgrade will not be undertaken until required, that is, until the last spare SLINK board fails and cannot be repaired.
SAC was pleased to see that MegaCam continues to experience a healthy PI subscription rate.
SPIRou:
SPIRou has seen a number of improvements/activities this last semester.
The new rhombs manufactured by Winlight in ZnSe provide a much higher transmission, especially in the blue (x2.5 gain) and even in the H band (x1.4 gain). These have significantly reduced image wobble, and no further gain is expected for these components.
Agitators are now operated with a more robust and faster control system.
Cooling of the Cassegrain unit to about 0°C is meant to reduce the SPIRou background. For this to work, a design with 8 cold plates of copper glued to the side of the unit has been explored. Isolation from the telescope will be realized with a 3mm spacer. A test to confirm the simulations is being planned. However, prior to that modification, the stabilization of the field lens into the Cassegrain unit must be solved.
The Fabry-Pérot acting as a reference for RV measurements is now thermally stabilized to 1-2mK. The LFC is only used for calibration and some work is still required before the LFC can be used during observations.
The absolute drift in RV measurements at the level of 7-8m/s is expected to be correlated with Coudé room temperature variations, though tests did not allow to demonstrate such a correlation yet.
SAC is pleased to see that CFHT is now running the same version (v0.6) of the DRS as at the Université de Montréal, while historical data are being reprocessed. However, at the moment, the reduction of polarimetric data is done outside of the DRS, thus causing delays in data transfer to the CADC.
The upgrade of SPIRou being prepared by IRAP and CFHT will require that the cryostat be opened. It will mainly consist in replacing the slicer and its octogonal fiber to improve the scrambling of the fiber modes, and hence increase the RV stability. Moreover, an investigation of the origin of the RV shifts based on interferometric measurements is being planned. And, last, an LED will be installed in the cryostat as a flat-field source in order to reduce persistence which impacts RV precision. Some equipment is being procured for the alignment of the optical system. Initially planned early next semester, the decision to go should likely take place following several conditions required by CFHT are met, namely: that Winlight and IRAP provide (1) a performance report for the spare slicer and a test report for scrambling, (2) an identification of all major risks together with mitigation; (3) a plan for the interferometric tests, and (4) an assessment regarding whether or not the detector should be moved to allow the access to the slicer, while possibly affecting focus and wavelength solution.
SPIRou+ESPaDOnS co-mount:
The idea of mounting ESPaDOnS and SPIRou in parallel and feeding both simultaneously through a beam splitter is continuing to be evaluated by the CFHT engineering staff, with the collaboration of an internship student at the Institut d’Optique in Paris. The preliminary conclusion was that this simultaneous mode of operation would likely lead to the loss of polarimetric capability. The study is thus shifting to the less ambitious goal of mounting both instruments in a way that will allow quick exchanges, from one night to the next, without involving personnel at the summit. This would allow, for example, to spend one night with SPIRou studying exoplanet transit events and then go back to ESPaDOnS. Or vice versa, to briefly interrupt a long SPIRou run to intercalate some urgent ESPaDOnS observations. SAC considered this quick exchange approach to have great interest and merit, leading to a sometimes-needed increase in the flexibility of scheduling. A few examples of science that would have been enabled by the SPIRou+ESPaDOnS quick-exchange system in previous semesters were mentioned. This would also help to alleviate issues with SPIRou scheduling and thus increase the efficiency of monitoring programs. The experience gained with this mode of operation could eventually lead to developing the capability of exchanging these two instruments during the night.
It was estimated that this project could be developed within the timescale of one year, assuming no worsening complications related to COVID-19.
Dome vents and machine learning:
SAC was delighted to learn that the re-coating of the mirror could be scheduled in late October 2020, despite all challenges caused by the COVID-19 pandemic, and that the procedure was very successful. The characteristics of the mirror after recoating are very good — with a significant increase in reflectivity over all wavelengths — and reveal a uniform and thick coating that is the consequence of further upgrades to the aluminizing chamber. This is the thickest coating ever measured over at least the last 13 years. SAC commends the team that led this effort, especially under the strenuous COVID-19 conditions.
To further efforts to extend the duration of the mirror coating, a mirror-condensation system was designed with a camera at the edge of the mirror to more reliably track the onset of condensation. Combined with a recently installed dry-air system, this device should limit the amount of condensation forming on the mirror and decrease the degradation of the mirror coating over time.
CFHT has made good progress on the new hydraulics system that will replace the faulty system that led to a significant downtime in 2020A. The new system was manufactured in Sept 2020 and is ready to be installed once the limitations from the COVID-19 situation subside. Additional repairs and upgrades to the current bridge crane were performed and it was recertified.
Operation of the dome vents at 2/3 heights has proved unreliable, especially during bad weather. The vents remain closed as of Oct 2020 and will remain so until an appropriate boom-lift can be acquired to ensure the vents can be freed should problems occur when they are opened. CFHT has purchased the boom-lift replacement and is awaiting delivery. The new lift will have a higher weight capacity and will allow two staff to access the crane and dome vents for regular operations. The boom-lift replacement should be available in the coming months, ensuring the dome vents can be used again.
During shutdown, the engineering team made extensive progress on the Dec wrap modifications to better hold and handle the large amount of cables in the wrap. CFHT has also made progress on the design and manufacturing of the mount for the new astrometric camera so it can be installed in a more beneficial location on the telescope, with no vignetting. The final integration of the camera is anticipated to resume shortly.
The Technical Observing Support team to keep track of emerging issues is now in place and should ensure a reliable tracking of difficulties and repairs. Software activities have focused on the new work-from-home status at CFHT, which required significant attention over the last semester. The software team is to be commended for the smooth transition.
Risk assessment and mitigation:
SAC was impressed by the detailed and thorough risk assessment spreadsheet assembled by CFHT. The level of detail is sufficient to define the critical elements of the observatory without getting too far into the weeds. The choices for the levels of risk and the evaluation of the impact on science, personnel safety, etc., have been thoughtfully selected, though some fine-tuning is still proceeding. This tool will provide excellent guidance to the staff on the areas of most concern and pressing need. The CFHT team is now using the risk register to guide priorities for the engineering tasks throughout the observatory. SAC looks forward to updates to the risk register as the risk definitions are finalized and eventually as top risks are retired.
Large Programs
VESTIGE:
The May 2020 SAC report for this LP still largely applies. SAC and CFHT are keenly aware of the current predicament that VESTIGE is facing and continue to make every reasonable effort to bring the completeness rate to a competitive level (at least 80%). SAC is confident that the overall requirements of the VESTIGE team should soon be met, modulo unforeseen technical complications or bad weather.
CFIS:
Though the overall completion rate of CFIS is becoming healthier, the survey is lagging behind in the 12-14 hr RA range. SAC noted the request to focus on longer (2 week) observing runs, particularly in the spring and summer, but reflected that this must be balanced against observing conflicts with VESTIGE and other PI programs. Tension remains between the observatory and CFIS-team data validation rates and we invite CFIS to approach CFHT to resolve discrepancies. SAC was pleased with the scientific output of CFIS thus far and congratulates the team on their work.
SIGNALS:
The SIGNALS program had high completion rates in early semesters but has suffered in 19B and 20A due to the crane malfunction, bad weather, and the COVID-19 shutdown. With the COVID-19 reduced modes of operation, SITELLE was not on the telescope for many months and SIGNALS has now fallen behind. The SIGNALS team is publishing papers and has created an attractive website with all survey information, including links to publications and survey status, consolidated in one place. The SIGNALS report was too brief once again, and did not provide an update on plans to provide the fully-calibrated spectral-line fitting software available to the entire SITELLE community. SAC would prefer to see a more substantial report from this team.
SLS:
SAC was pleased to see good progression of the SLS over the two most recent semesters, during which both the validation and completion rates have reached healthy levels. This is a significant improvement over the previous period. In addition, the ratio of validated-to-requested number of visits per target increased significantly in 2020B, likely because of changes in the allocation planning that were adopted by CFHT following discussions at the last SAC meeting. This increased monitoring rate of targets will greatly help achieving denser phase coverage and better stellar activity filtering, leading to improved sensitivity for planet detection and stellar magnetism studies. Still, despite the good news, it remains likely that the SLS will not reach at least 80% completion by the end of their current allocation; this will be discussed further at the upcoming midterm review of this LP.
SAC was also pleased to learn about the significant improvements made to the data reduction software by the team and the latest results achieved in terms of radial velocity (RV) precision. SPIRou can now deliver RV precision of 1-1.5 m/s over short timescales or 2-2.5 m/s over a timescale of months, making it the most precise infrared RV instrument currently in operation. SAC also notes the good progress the team has made on the modelling and removal of detector persistence effects and on the analysis methods for low SNR targets.
SAC noted the concerns expressed by the SLS team about some aspects of the schedule that are not optimal for their target monitoring, namely that the length of some SPIRou runs are too short and that SLS observations sometimes suffer interruptions due to transit observations. At the same time, SAC is aware of the many constraints faced by CFHT in making the overall schedule and ensuring fairness across all programs. Under the circumstances, SAC believes that CFHT is doing a good job in responding to demands while ensuring fairness. Going forward, SAC encourages cordial interaction and consultation between CFHT and the SLS team in developing the schedule.
Many interesting scientific results were obtained recently by the SLS team, including the discovery of a brown dwarf companion around the low-mass star TOI-1278, the measurement of the spin-orbit alignment of the planet AU Mic b, and the characterization of magnetic activity for the pre-main sequence star DoAr44, to name a few. Several papers have been published or are in preparation on these and other discoveries. These results are very encouraging and SAC congratulates the team.
SAC thanks the SLS team for their detailed and informative report.
Future rounds of LPs and completion reviews:
Despite all the acquired delays and past problems, LPs are now progressing at a reasonable pace, so that their completion could be forthcoming. SAC anticipates that, in the case of favorable circumstances, a new round of Large Programs at CFHT may possibly start, optimistically, as early as 2022B. It is expected that CFHT will be still operating in its current incarnation at the horizon of 2025-2026. This new round of LPs should thus be able to complete before the advent of MSE. Depending on progress, weather, unexpected technical problems, and upon the decisions of the completion reviews sub-committee, the start of new LPs might be postponed by one or two semesters, thus in 2023. Future SAC reports will provide more details on the expected schedule. Nevertheless, SAC encourages the CFHT community to start the planning of proposals for the next generation of LPs.
SAC expects that completion reviews, possibly of all LPs, will be triggered at the next SAC meeting in May 2021. Accordingly, LP PIs should submit appropriate detailed reports in time for the next SAC meeting to inform the work of the completion review sub-committee. LP PIs should be aware that the completion reviews will use as a reference the validation rates provided by the observatory and are encouraged to approach CFHT in case of discrepancies. Following the May 2020 SAC recommendation, CFHT is now providing a table on their website, updated at least monthly, with validation rates for all LPs.
Time Allocations:
Time losses in 2020A: Unlike previous semesters, the time lost to technical problems in 2020A was remarkably small, with only 1.5 nights (due to cables being caught on bolt heads of the DEC bearing). Weather losses were usually at the average level of 25-30%, but two runs were badly hit at 50-80% in Feb and March. The main loss in 2020A was 43.5 nights between March 24 and May 6 due to the Covid-19 stay-at-home order. During this period, a few SPIRou zenith spectra could still be taken for telluric modeling and MSE, which the SAC appreciates.
Time allocation for 2020B following ITAC and LP allocations was distributed amounting to 69 nights on SPIRou, 39 on MegaCam, 22 on SITELLE, 21 on ESPaDOnS, and 19 on WIRCam.
The DDT time allocations amounted to 1.3 nights in 2020A, half of which went to high school programs. The engineering (E) time use was also very small, 0.4 hours in 2020A. Similar numbers are currently foreseen in 2020B with 0.9 nights of DDT so far and 1.2 hours of E.
Overall, the time pressure in 2021A is maintained at a healthy level, reaching 2.5 on average for NRC and CNRS+Opticon, and shows a trend for a slight increase since 2013. The trend of high demand for high resolution spectroscopy from normal programs continues. SPIRou was again the most popular instrument with more than 313 hours requested, followed by MegaCam (214h) and ESPaDOnS (211h), WIRCam (145h) and SITELLE (100h). “Bright time” requests thus amounted to 669 hours and dark time to 314 hours for PI programs.
QSO:
The QSO system is continuing to demonstrate its high efficiency and robustness, allowing CFHT to deal with the many and diverse observational constraints coming from the different instruments and projects, optimizing the use of observing time.
Semester 2020A was challenging, due to the 43-night shutdown from March 24 to May 5 following the stay-at-home directive from Gov. Ige in response to the COVID-19 pandemic. The observing schedule had to be revised, and some instrument runs had to be removed. The observatory took initiative to limit the damage for MegaCam (13% loss) and SPIRou (3% loss) observing to limit overall impact on the ongoing LPs. SITELLE (54% loss) and WIRCam (68% loss) runs were instead most affected, thus including the SIGNALS LP. ESPaDOnS losses were intermediate (29%). SAC is pleased that a large fraction (>80%) of observing time was validated for MegaCam, WIRCam and ESPaDOnS, numbers are not yet available for SPIRou and SITELLE. The overall completion rate for many instruments and agencies was obviously negatively affected by the shutdown, with variations across them inevitable given the situation.
A transit visualization tool has been developed by CFHT to help scheduling of transit programs. In fact, several accepted PI programs requiring transits observations, including highly rated programs, got only a few or no-data at all, because requesting scheduling on adjacent nights of transits with similar RAs. Following a recommendation from the May 2020 meeting, SAC has requested to avoid such observations when possible, to enhance the monitoring efficiency of the SLS Large Program. This measure has proved effective, with an increase of the monitoring efficiency of SLS from 50% before to 80% after the SAC Recommendation was implemented. However, the completion rate (the ratio of validated to allocated time) of A- and B-ranked PI normal programs on SPIRou was modest, at the 46% on average, and as low as 38% for Canada (who had the largest time request in absolute terms and also in terms of number of transits), while the completion rate of SLS was at 95%. SAC realizes that this is putting extra pressure on PI programs requesting transit observations, but thinks that this could be mitigated at the ITAC meeting stage and through optimized scheduling. SAC will continue to monitor the situation.
Semester 2020B has started strong, without noticeable observing problems so far. A one-week shutdown for mirror re-aluminizing that had to be postponed from previous semesters took place in October. Departure of two Resident Astronomers is putting some pressure on the team, discussion for hiring of replacements is underway.
Phase 2 for SPIRou is being successfully handled by the new kealahou software tool. Work is ongoing to add more functionalities to the tool and move the next instrument over
GRACES:
The demand for GRACES is declining among Gemini PIs, although the instrument is now being used by two LPs. SAC wishes to receive an update on the status of the Gemini LPs using GRACES and the remaining commitments to these programs.
A CFHT-Gemini call for proposals for French PIs was open from September 1 to October 1 2020 and only one proposal was submitted, requesting 3 hours of telescope time on NIRI at Gemini North. This is less than the 18 hours of available Gemini time and so there is now “banked” time for French PIs for future semesters. CFHT should make sure this time is properly tracked and remains tagged as French time rather than going into the general pool of time available. SAC encourages wide advertisement of this available time for all instruments on Gemini North and Gemini South to French PIs. We anticipate that about 33 hours of Gemini time will be offered to French scientists through the 2021B CFHT call for proposals.
PH1 tool:
The Northstar web application has been used for 10 years by PIs and agencies to submit and collect proposals and by the FTAC to perform evaluations. Several problems can arise with this application, and in particular in the last call for proposals, the science justification of 1 proposal as well as the technical justifications of 2 proposals were deleted and had to be recovered from PIs. A solution must be found to avoid these critical issues (and some less critical) permanently. One would be to obtain the source code of Northstar to fix problems in a transparent way at the benefit of PIs and FTAC. Alternative solutions should be considered like using other existing tools, or implementing Ph1 into Kealahou. Contacts have been taken with developers of similar applications like those used at AAO and EAO, although those tools would need adaptations (the recent Ph1 ESO tools is to be considered too).
MSE:
The MSE science team currently includes more than 422 members from 39 countries, most of them from the 8 MSE full members (now also including Kyung Hee University in South Korea) and 2 observer members. The breadth of the science covered by the Working Groups is impressive. The team, under guidance from the Project Office (PO) and the Project Scientist, is currently focusing on creating the Design Reference Survey that helps guide and update the MSE requirements, conceptual design, and identify the software infrastructure requirements. This DRS is designed to produce a detailed observing plan with large, key surveys (Milky Way halo star metallicities, "cosmic noon" survey of galaxies, AGN reverberation mapping, cosmology).
The PO is currently focusing on the Preliminary Design Phase Readiness Review, scheduled for the end of 2021. This work updates the design to take care of the outcome of the conceptual design review; details the redevelopment of the telescope; describes the updated design of the most challenging aspects of the spectrographs (HR that now has an echelle design, possible because of relaxed requirements, and LR that now splits the visible and IR spectrographs); and puts together the documents that describe the updated state of the project.
The PO further refined the design of the complex Program Execution System Architecture (PESA) that needs to handle all aspects of data handling, from the survey preparation, to the calibration, science pipeline, and definition to the science archive and platform. SAC is pleased to see that experts from the MSE partners are now directly involved in the development of PESA, which should help further progress.
The MSE Project Office has continued to participate in various community reviews over the last year: Astro2020 and Snowmass 2020 in the US, the Canadian Long-Range Plan 2020, the French CNRS/INSU “prospectives” for astronomy and astrophysics, and the Australian mid-term review. Sam Barden joined the PO in Feb 2020, bringing substantial experience on multi-object spectrograph design. The PO is also in the process of hiring a new system scientist and a project administrator. Finally, despite the COVID-19 situation, the MSE community met online through a series of telecons for an All-Hands Meeting spread out over the month of October 2020; all talks are available online and provide a good overview of the project status.
The next MSE Science Team in-person meeting could happen in Nice in 2021, at a date that depends on the evolution of the pandemic situation.
SAC was pleased with the overall work from the Project Office and Science Team that paves the way for the Preliminary Design Survey and Readiness Review.
Operational and Development Priorities:
- Normal operations
- SPIRou, DRS, Upgrade and Kealahou
- MSE
- Risk assessment and mitigation
- SPIRou and ESPaDOnS co-mount
CFHT agrees with these priorities and anticipates being able to make progress in all of these areas over the course of 2020.
Next SAC Meeting
The next SAC meeting will take place May 5-7, 2021. It will be hosted by Laura Parker in Hamilton, Ontario, Canada, if international conditions permit safe traveling. A remote meeting will be held on the same dates, otherwise.