Canada France Hawaii Telescope
88th meeting of the Canada-France-Hawaii Telescope
Scientific Advisory Council
Waimea, 18-20 November, 2015
Note: The report presented below is the public version of the SAC report as amended by the CFHT Board of Directors in accordance with the CFHT Communications Policy.
After deliberation during its December 2015 meeting, the CFHT Board of Directors, in consultation with the Executive Director, took note of the following SAC’s recommendations:
| Recommendation 1 | Time accounting for instruments |
| Recommendation 2 | WIRCAM observing time accounting |
| Recommendation 3 | WIRCAM filters |
| Recommendation 4 | ESPaDOnS default mode |
| Recommendation 5 | Instrument status and report history |
| Recommendation 6 | Science verification for SITELLE |
| Recommendation 7 | Support astronomer for SITELLE |
| Recommendation 8 | SPIRou - Engineering-grade detector |
| Recommendation 9 | Progress reporting on SPIRou |
| Recommendation 10 | Observations at Gemini - allocation of time |
| Recommendation 11 | Operational and development priorities |
| Recommendation 12 | Future LP reports - front home page format |
| Recommendation 13 | LP proposal deadline |
| Recommendation 14 | LPs - Agency Time Allocation announcement |
| Recommendation 15 | Large Programs - Selection procedure |
Report of the 88th meeting of the CFHT Scientific Advisory Council,
November 2015
The 88th CFHT Scientific Advisory Council meeting was held in Waimea on 18-20 November 2015. SAC members Hervé Aussel (vice-chair), Stéphane Courteau, Magali Deleuil, Tristan Guillot, Andrew Howard, Rodrigo Ibata, JJ Kavelaars, Marcin Sawicki (chair), Kim Venn and Richard Wainscoat attended the meeting. Yen-Ting Lin from the Academia Sinica Institute of Astronomy and Astrophysics in Taiwan attended the meeting as invitee. The planned visit to the CFHT summit facility on the first day of the meeting was cancelled because of the ongoing confrontation on Mauna Kea. During the second and third days of the meeting CFHT Executive Director Doug Simons, Director of Science Operations Daniel Devost, Director of Engineering Derrick Salmon and a number of CFHT scientific and technical staff members made presentations and participated in discussions.
SAC was pleased to have presentations by the CFHT team members in accord with Recommendation 7 from the 86th SAC meeting. These presentations were either scientific, giving some examples of the researchers activities, or technical and related to the duties of the staff. On the latter, SAC notes that staff presentations provided a better overview of on-going daily work and gave concrete insights into results and possible issues. The format was greatly appreciated and SAC encourages the instrument scientists and other staff members to give technical and scientific reports during future SAC meetings in Hawaii.
During the meeting, SAC also heard a detailed update from the CFHT Executive Director on the ongoing confrontation on Mauna Kea related to the issue of future facility development and about the efforts that he, and CFHT staff, are undertaking to help resolve the situation. This crisis does not affect only TMT, but has potential negative implications for the future of all astronomy on Mauna Kea - including MSE - because of its potential impact on the upcoming master lease renewal. In the shorter term, it can affect ongoing operations at CFHT. We recognize that Doug Simons, as a long-term Hawaii resident, brings a well-balanced and well-informed perspective to the situation. His calm handling of the situation can continue to play a very important role at this critical time in this discussion. SAC is looking forward to the resolution of this crisis so that operations at CFHT can be assured to continue uninterrupted and the Executive Director can return fully to his normal duties.
1. Telescope use and scheduling report
SAC received reports on Time Allocation and Queued Service Observing (QSO). During 2015A the first three QSO runs experienced very large (nearly 80%) weather losses. The average loss over the semester was 27%. WIRCam was, again, the most affected (losing 35% of its time) followed by ESPaDOnS (27%) and MegaCam (24%). SAC congratulates CFHT on achieving a VERY low technical loss time in 2015A, 1.3%, which is very helpful at all times, and particularly during such poor weather. Completion rates for A programs were >85% for all three instruments. Completion rates for B programs varied: 83% for ESPaDOnS, and 63% for WIRCam and MegaCam. Overall, QSO achieved a completion rate of 71% for all programs, 91% for A and 72% for B and C.
In reviewing the telescope performance during the May 2015 meeting SAC noted that the WIRCam overheads were not compatible with the recorded exposure times in the CADC archive and requested an investigation of the discrepancy. SAC received a detailed report on WIRCam usage prepared by Pascal Fouqué. SAC found this report to be very helpful. The report showed that a significant amount of time during the night was unaccounted for. SAC continues to be concerned by these discrepancies as they directly impact the ability to correctly plan and allocate observing time for the Large Programs and for agency time balancing. SAC encourages CFHT to continue its detailed accounting of time usage during the night in order to unearth possible inefficiencies, with the goal of improving open shutter observing efficiency. SAC believes that this exercise would be useful for all instruments — not just WIRCam.
SAC examined the ratio of PH2 user charged time (exposure time plus read time) to allocated nights for WIRCAM for the 13B semester through to the latest run in the 15B semester, and found that 5.0 hours of chargeable time was being delivered per night. This is significantly less than the 6.0 hours/night ratio presently being used when scheduling the telescope.
SAC believes that it is important that realistic numbers of hours per night for all instruments are used, particularly in the context of the upcoming call for large proposals.
SAC also believes that it is urgent to establish a conservative (robust) estimate of delivered science hours per night for SITELLE, and that this should be done soon enough for it to be useful for teams submitting Large Program proposals; SAC hopes that a reasonable value can be established from the commissioning and science verification observing runs. This information should be communicated to the CFHT community as soon as reasonable (and prior to the LP proposal deadline) with a warning regarding the likely range of uncertainty associated to the estimate.
RECOMMENDATION 1: |
RECOMMENDATION 2: |
The above two Recommendations are critical for the upcoming LP call and need to be acted upon right away. Relevant points are addressed further in Section 6 and Recommendation 14.
2. Operation Status and upgrades
MegaPrime / MegaCam
SAC reviewed the calibration work that has been done with the new ultra-broad gri filter for MegaCam. While more flat-field testing could be done, SAC is convinced that the current characterizations are good and sufficient for the current and known science applications (fringe removal is <4%).
SAC reiterates Recommendation 5 from its May 2015 meeting that observing programs should use the new filter set unless a strong science case is made in the proposal for the need of the old filters. The old filters should be decommissioned by 2017A. Again, the CFHT user community needs to be informed of this policy during the 16A proposal and Large Programs calls.
WIRCam
WIRCam observations suffered significantly from poor weather this semester. Two new filters proved to work well. A detailed accounting of the actual number of hours available per night to each instrument showed that WIRCam is significantly lower than the currently-assumed 6h per night (see discussion above).
RECOMMENDATION 3: |
ESPaDOnS
ESPaDOnS is working well, and the new software pipeline OPERA shows improvements in flat fielding, normalization, and wavelength calibration in most cases. Several modes of operation have not yet been tested with OPERA, e.g., polarization studies. CFHT staff are currently providing both OPERA and Libre-Esprit data to PIs for comparisons, and requesting comments and feedback. The two-amp mode is now ready, which reduces the data readout time by half. Currently, the two-amp mode can only be reduced with OPERA. If users demand Libre-Esprit in the future, a software wrapper may be necessary for observing with the two-amp mode.
RECOMMENDATION 4: |
TCS Upgrade
The new TCS hardware was released for operation in March and all four instruments have working pointing models. The archaic RBUSS, a communication bus system that the previous TCS used to access remote devices on the telescope, is currently being replaced.
Instrument status and history reporting
SAC is pleased to hear that instrument status and history are now being recorded on dedicated pages in the CFHT website.
RECOMMENDATION 5: |
3. Development status report
SITELLE
SAC was very pleased to learn of the good progress in the commissioning of SITELLE. This instrument appears to be very promising and may contribute significantly to the scientific output of CFHT over the coming years. CFHT has received letters of intent to submit proposals to use this new instrument in the coming round of Large Programs. However, unless the results of science verification are available sufficiently well in advance, SITELLE proposers will be disadvantaged with respect to proposers of programs on other instruments.
RECOMMENDATION 6: |
SAC is concerned that support for a major scientific instrument relies on an external non-staff member.
MegaCam upgrades
Work is proceeding to attempt to increase the readout speed of MegaCam, and some small gains of approximately 4 seconds per exposure have been shown to be possible using engineering chips. We encourage CFHT to continue exploring this upgrade for its flagship imaging instrument. Based on historical usage, a reduction of 1 second in MegaCam readout equates to 0.5 nights of dark time per year.
SPIRou
SAC congratulates CFHT for finding an innovative solution to supply an engineering-grade detector for SPIRou construction, a solution that will also allow an upgrade to a science-grade detector when these become available. SAC notes that while the SPIRou progress report envisions a delivery date for the engineering-grade detector at the end of 2015, a later delivery, around late March 2016, was envisioned by CFHT Director of Engineering Derrick Salmon. While we understand that delays can arise, we stress that it is essential to do the most to keep SPIRou’s progress on track. We are looking forward to seeing the engineering-grade array arrive as soon as possible for instrument tests and then to the science-grade array being ordered and delivered in a timely manner for science operations.
RECOMMENDATION 9: |
GRACES
SAC was informed that six nights of Gemini Telescope exchange time have now accumulated. This time is compensation for the access to ESPaDOnS that Gemini users have enjoyed thanks to the GRACES facility.
MSE
Unfortunately, there was no time to hear about MSE progress during the meeting. However, SAC is looking forward to hearing a full progress report on the MSE project at its next meeting.
4. Operational and development priorities:
In addition to the above work priorities SAC also notes the importance of the MSE project. This project runs in parallel to CFHT operations and development work and care must be taken to not let it affect this work.
5. Ongoing Large Programs
SAC received and discussed progress reports from OSSOS, BinaMIcS, HMS, Luau, MATLAS, and MaTYSSE.
SAC feels that OSSOS, MaTYSSE, and HMS programs are making good progress and has no concerns going forward. There are no serious issues with observing, scheduling, data reductions, or other aspects of these programs.
The newly-begun Luau project is also making good progress now (2015B), although it had low completion in 2015A due to RA pressure. This situation needs to be monitored and -- if needed -- adjustments made to the program objectives and schedule priorities.The Matlas LP has concluded observing, with a lower-than-hoped-for validation rate of 54%. This low validation rate is due to the challenging nature of the program: the program requires photometric conditions and particularly dark skies, with conditions guaranteed to be stable for a sequence of at least 7 exposures.
BinaMIcS observations are proceeding efficiently but SAC notes that the detection efficiency of magnetic fields in the Survey Component is lower than expected. SAC wonders how this lower SC detection efficiency affects the Targeted Component follow-up observing program. The BinaMIcS team should assess and report to SAC how this impacts the time needed for the LP as soon as possible.
Finally, SAC thanks all LP teams for providing progress reports as requested. SAC notes that to simplify reporting in the future, certain information (such as validation rates etc.) should be reported in a format that is standard for all LPs.
RECOMMENDATION 12: |
6. Future Large Programs
CFHT has received 10 letters of intent led by researchers from the Canada, France, and Hawaii Agencies. Time on all four CFHT instruments is being requested, and a rough estimate on the pressure is about a factor 3. This number is subject to change since the letters were neither mandatory nor binding, and some letters did not specify the planned time request.
SITELLE is among the requested instruments but, despite promising results, this instrument’s commissioning was not yet fully complete at the time of the SAC meeting. At the completion of the commissioning, CFHT will communicate the instrument’s measured sensitivity. A short science verification run will follow commissioning, with data released immediately to the community in early January 2016. SAC feels that teams aiming for a SITELLE Large Program should have some time to assess the feasibility of their proposals in light of these data and a modest delay in the LP proposal deadline is therefore advisable.
RECOMMENDATION 13: |
Experience with CFHT shows that the effective observing efficiency of a new instrument, i.e. the average number of hours of open shutter science plus readout time per night, is not known until a few semesters of observing have elapsed. Hence, SITELLE observing efficiency can only be estimated at the time the LP proposals are due. CFHT should provide this estimate and proposers should be made aware of its value prior to the LP deadline. SITELLE proposals should contain provisions if the observing efficiency (hrs/night of open shutter time) of SITELLE is noticeably different from the ab-initio value.
SAC heard the concern that the selection process of the Large Program should be free of conflict of interest. However, SAC notes that due to the legacy nature of the Large Programs, each proposal is expected to have support from a large group of interested researchers, as demonstrated by the letters of intent, so that a fully non-conflicted Time Allocation Committee would have to be recruited from outside the CFH community; while desirable from one standpoint, a non-CFH TAC would not be able to properly weigh the benefits of the Programs to the CFH communities. SAC also notes that the CFH Agencies’ time allocation committees constitute a body of specialists in all areas of CFH science and comprise users of the facility who already follow procedures to select the best science without conflict of interest. To address these issues, SAC recommends the following procedure for the selection of Large Programs:
7. CFHT Users’ Meeting
SAC heard a report on the planning for the next CFHT Users’ Meeting to be held at the St Paul Hotel in Nice on 2015 May 2-4, with a SAC meeting on May 5-6. A conference webpage is being finalized by the CFHT staff to be ready for the end of November. The meeting will include registration fees to cover the cost of lunches (included).
The LOC is composed of Doug Simons (chair), Ferdinand Babas, Tristan Guillot, Vanessa Hill, Alyssa Jensen, Lison Malo, Sophie Maurogordato, and Mercédes Stevens. The SOC is composed of the SAC members.
The deadlines for Abstract submission and Registration will be set to 1 February 2016 and 1 March 2016. An issue was raised about the time necessary to prepare and print a book of abstracts; however the SAC feels that a book of abstracts is no longer required as all the information will be available online.
SAC is also informed that the SPIRou team wishes to hold a meeting coincident with the CFHT Users’ Meeting and probably on 5-6 May. Because May 5 is a holiday, this would be done at the St Paul hotel as well (rather than, e.g., at the Observatoire de Nice), where the SAC meeting will also be held.
8. Adaptive optics instrument proposal
SAC reviewed an unsolicited proposal titled ‘Development of the First High-Performance Portable Adaptive Optics for CFHT’ from D. Ren et al. from Nanjing Institute of Astronomical Optics & Technology. SAC thanks the proposers for their interesting and scientifically well motivated vision for adaptive optics (AO) instrumentation at CFHT. The proposal laid out plans for a possible AO system for CFHT focusing on a natural guide star (NGS) operations and correction of non-common path errors. While the proposal was scientifically interesting, it does not fit into the current CFHT priorities that are driven by our communities.
9. Next SAC Meetings
The next SAC meeting will be held on 2016 May 5-6 in Nice, France, immediately following the CFHT Users’ Meeting.