Report of the 76th meeting

of the Canada-France-Hawaii Telescope

Scientific Advisory Council

Waimea, Hawaii, 12 – 14 November 2009


Recommendation 1 FITS header DIMM information
Recommendation 2 continuation of IQ studies
Recommendation 3 dome ventilation
Recommendation 4 declination pointing problem
Recommendation 5 alternatives to SPIRou
Recommendation 6 Science cases with spectropolarimeters
Recommendation 7 science with `IMAKA
Recommendation 8 support to SITELLE
Recommendation 9 hours - night factor
Recommendation 10 Elixir-LSB
Recommendation 11 accessibility of CFHT LS data
Recommendation 12 LP vs PI competition


SAC members Mark Chun, Pierre-Alain Duc (chair), Laura Ferrarese, Brett Gladman (vice-chair), Cecile Gry, Robert Jedicke, Denis Mourard, Coralie Neiner, Gregg Wade and Jon Willis attended the meeting. Hiro Takami, from the Academia Sinica Institute of Astronomy and Astrophysics in Taiwan, attended the meeting as an invitee. The CFHT director Christian Veillet, Derrick Salmon, Daniel Devost, Jean-Charles Cuillandre (for CFHTLS), Sarah Gajadhar, Kevin Ho, Olivier Lai and Nadine Manset participated in presentations and discussions.

1. Science talk

Following the decision of the SAC to include in its yearly meetings in Waimea a scientific talk to the CFHT staff and the SAC members, Gregg Wade presented a study on the magnetism in massive stars. He also reported on the preliminary results of MiMeS Large Program.

2. Technical activities

Derrick Salmon reported on the technical activities for the period May 2009 - November 2009. Following discussions with CFHT staff, SAC recommends the following development priorities for the coming months

  1. Operational Priorities
  2. Observatory Automation
  3. Development of SPIRou
  4. Dome venting and IQ studies
  5. Development of `Imaka
  6. Investigation of the telescope declination problem
  7. Development of Sitelle
MegaCam operation

MegaCam has suffered minor problems during the last semester: they are related to the sensors in the filter jukebox, to the PLC control of the shutter and to the guide star acquisition at high airmass. They caused small losses in telescope time.

A routine maintenance operation was performed in July. Two persons from CEA-Saclay were invited to assist and participate in these operations. The close inspection did not reveal any serious issues. CEA engineers noted that the filters' sliding along the rails had deteriorated since last visit, though no signs of an excessive wear were found. This was tackled by lubricating the system.

WIRCam operation

No problem was reported for WIRCam. A new mode of observations allowing steering/fast readout has been implemented.

Loic Albert, who until now was in charge of WIRCam (on the software side), is about to leave CFHT. CFHT is currently seeking his replacement.

ESPaDOns operation

Following the recommendation of SAC, a new red-sensitive EEV CCD with two amplifier readout was ordered and delivered to CFHT. Nadine Manset informed SAC that the Libre Esprit environment will be updated to cope with this change of CCD. It is planed to initially function with the one amplifier option.

Given the requirement of the community to have access to an alternative pipeline, SAC retains its recommendation to develop a new open-source code which will be compatible to the two amplifier readout mode. SAC was informed that the code developed at IfA by Dave Harrington may be used for that purpose. A formal agreement with the associate director of IfA, Jeffrey Kuhn, is in progress.

The new CryoTiger cooling system, which will replace the liquid nitrogen cooling, has been received and will soon be installed. A breakthrough has occurred in understanding the long-standing issue of the polarization crosstalk. The ADC prisms have been discovered to be a source of strong, variable crosstalk - in fact the dominant source of the problem. On the other hand, the optical triplet, which was the main original source of crosstalk, no longer appears to contribute significantly, thanks to its replacement. The ADC crosstalk may be due to stress caused by the glue joints used to mount the prisms into their aluminium cells. New prisms have been purchased and a new holding mechanism implemented. Preliminary lab tests are very encouraging. Further tests are planned on the telescope during the coming runs. It will be up to the ESPaDOns users to claim success.

SAC thanks the CFHT team for all the major efforts made over the last months to understand and work out solutions.


Unfortunately the `Ohana science run at Keck failed due to a failure of the adaptive optic system. No other observing run is yet planned due to the difficulties in obtaining telescope time.

On the other hand, the `Ohana-iki project has made progress. The first `Ohana-iki telescope has been built and fiber injection tested. The measurements show that the system will work with stars brighter than J=0. The second telescope has been ordered and first interferometric observations are planned for early 2010.

CFHT environmental, seeing and image quality studies

SAC was given several very detailed documents pertaining the seeing and image quality at CFHT. They attest the renewed priority given by CFHT on the IQ issue and the tremendous efforts made during the six last months. These studies were made possible by the richness of the MegaCam image database, the availability of new instruments and tools such as the CFHT in-dome DIMM and Mauna Kea Atmospheric Monitor (MKAM), and above all the dedication of several CFHT staff and external researchers, including among others René Racine, Derrick Salmon, Olivier Lai and Mark Chun.

SAC congratulates the team for this achievement which should have a significant impact on the future of CFHT.

The MKAM was successfully completed thanks to the collaborative efforts of four Mauna Kea observatories. A new arm and pedestal resp. holding the wind sensors and rain gauge had to be installed as well. The seeing at 7-m elevation and turbulence structure parameter Cn2 at 6 different altitudes are measured every 90 seconds by a Differential Image Motion Monitor (DIMM) and a Multi-Aperture Scintillation Sensor (MASS), archived and made publicly available through a dedicated web server.

Recommendation 1: FITS header DIMM information

SAC recommends that the MKAM DIMM information is included in the fits header of the images produced at CFHT, once CFHT feels that the information is stable and reliable. The data from the slit DIMM could also be included if CFHT judges this appropriate

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The correlations of the data from the out-door, in-dome DIMM and MegaCam IQ measurements with time, temperature, direction and speed of wind, etc., leads the Racine et al report to conclude that the observatory itself is the dominant cause of degradation of natural image quality at CFHT, and not the ground layer turbulence at the site. The 'Imaka studies favor a stronger contribution from the ground layer. Continued study will determine the strengths of the two contributions. Dome/telescope effects may account for some unexpected trends found during this monitoring campaign: in particular the IQ degrades during the night and is the poorest at zenith.

Recommendation 2: continuation of IQ studies

SAC recommends CFHT continue the campaign of ongoing coordinated outside-DIMM/MASS/MegaCam measurements, complementing it by optical turbulence measurements.

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The optical turbulence measurements should be made up to an elevation of at least 20-m above grade at the DIMM site, as suggested in the report of René Racine. SAC was informed that lunar scintillation studies (performed by PhD student T. Pfrommer, working under Paul Hickson) will also provide valuable information.

Racine's report regarding the atmospheric and telescopic contributions to the seeing concludes that the IQ delivered to the telescope could be significantly improved by dome ventilation. The heat source management which also helps with the IQ has already been optimized.

Although the post-ventilation IQ delivered on the instruments cannot be precisely predicted, SAC estimates that there are already enough pieces of evidence that the probability of improved IQ is very high and may reach a median improvement of 0.1-0.2 arcsec (with the most likely improvement later in the night once the dome air has been flushed, as opposed to the current state where the IQ mildly degrades through the night). Although it is clear that dome ventilation would eventually benefit `Imaka (if it is built), SAC feels that the sooner this improvement can be implemented, the more the current instrumentation, in particular MegaCam, would benefit.

Recommendation 3: dome ventilation

SAC finds the prospects of dome ventilation exciting and scientifically compelling. CFHT should proceed with dome ventilation as soon as possible with an emphasis on minimizing down time.

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SAC considers this to be a rather high priority and would like a report on the progress in May 2010. This report should include cost and scheduling estimates. Since an early implementation of dome ventilation is recommended, solutions that limit the scientific operations down time should be preferred, even if they mean a longer completion time.

Serious work to improve the primary mirror was presented in the Racine et al report as a second priority for improving delivered IQ. Although it is arguable that dome ventilation to 20% porosity (p=0.2) might in principle result in the same IQ improvement as a re-configured mirror, the telescope would have to be down for at least the 6 months required to ship the mirror away for reconfiguration. The scientific cost would thus be much greater than that of the dome engineering (for which scenarios with negligible down time are plausible).

Therefore, SAC does not think mirror improvement to be feasible until at least 2013 (after the current Large Programs finish), and even then the advisability of this will have to depend on the decisions related to other instrumentation (like `Imaka) taken before then. Indeed the current mirror imperfections may not be relevant to `Imaka's performance.


The progress on the All Sky Infrared Visible Analyzer (ASIVA) has been rather slow. The first acceptance tests at the vendor's lab have failed. A delivery is nevertheless still foreseen for spring 2010.

Observatory automation

The observatory automation project has made considerable progress and its completion should occur according to schedule, i.e. by the end of 2010. Several systems are in fact already available for remote observation. One major challenge will be the training of the personnel. It has in fact already started. Technical overheads during the 2010 Queue Service Observing are to be expected and are to be charged to engineering nights.

Declination pointing problem

The issue on the sometimes very poor declination pointing (up to 50 arcseconds off) remains. The replacement of several bolts in the dec gear box did not improve the pointing.

SAC finds such a situation very uncomfortable as it leads to observing overheads during the night (especially for ESPaDOns) and above all may be the forerunner of a serious problem with the telescope.

Recommendation 4: declination pointing problem

SAC recommends that CFHT resources be directed toward understanding  and correcting the declination pointing error.

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SAC was informed that the detailed analysis of the WIRCam acquisition frames may provide some clues on the origin of the problem.

AO activities

The collaboration on modeless laser studies with the Laboratoire de Spectroscopie Physique (LSP) will continue. The LSP has indeed decided to pursue these activities despite the rejection of a funding proposal by the Agence Nationale de la Recherche. Two CFHT staff (Olivier Lai and Christian Veillet) are currently involved in this project. The laser experiment (outside the CFHT dome) will be done in coordination with the Mauna Kea telescopes equipped with traditional Laser Guide Stars. SAC did not receive any detailed document on the scientific objectives of this project and has therefore not discussed its scientific impact.

Christian Veillet informed SAC that the AOB / Flyeyes activities will be suspended in 2010 for lack of manpower and prioritization for this project. In particular no engineering AOB night is planned. SAC agrees with this decision.

3. New instrumentation

Christian Veillet updated SAC with the various developments on the CFHT new instruments that had been recommended during the November 2009 meeting. Pierre-Alain Duc presented SAC a new possible wide field of view spectrometer that has recently emerged: Gyes.


Since SPIRou was accepted a year ago for a phase A financed by CFHT, SAC judges the technical developments on the instrument to have been very limited. Almost all the efforts have been devoted to discussions with the different partners and the setting up of the management plan. The latter was not even finalized at the time of the Nov. 2009 SAC meeting. The formal contract for the phase A study will be signed between CFHT and INSU, in France. The completion of the phase A study will not be ready before the May 2010 SAC meeting.

The lack of manpower is the main serious issue. The laboratory of the PI, the LATT, is currently deeply involved in the development of one second-generation VLT instrument, MUSE. Local resources should become available in 2010, as indicated in a support letter sent to SAC by the directors of LATT and Observatoire de Midi-Pyrénées. An optical engineer (who later may act as a system engineer) should soon be hired. Discussions about the involvement of the LAOG (Observatoire de Grenoble) have not yet succeeded. On the other hand, new Canadian partners have expressed their strong interest in joining the project. Taiwan should be involved as well for the detector development. Finally, SPIRou has recently been discussed during the prospective exercise of French astronomy organized by INSU. The group working on the future facilities ranked SPIRou as first priority in its cost range.

SAC states its strong worry about the lack of progress in the last year and the resulting further delay it implies for the installation of the instrument.

At the same time, the scientific interest of a SPIRou-like instrument on the CFHT remains very high, and might have even increased since competing instruments with similar global scientific objectives might not be financed. Christian Veillet informed SAC about the status of two such instruments: the UKIRT Planet Finder (UPF) and the Calar-Alto high-Resolution search for M dwarfs with Exo-earths with a Near-Infrared Echelle spectrograph (CARMENES). The UPF concept is based on the phase A study of the now abandoned Gemini Precision Radial Velocity Spectrometer (PVRS). The UK funding of UPF seems unlikely. Compared to SPIRou, CARMENES has a lower spectral resolution. Its funding will rely on the (uncertain and currently discussed) future of the Calar Alto observatory. Note that none of these instruments have a polarimetric mode. The studies already made for these instruments might be of use for SPIRou.

SAC feels that should SPIRou continue to face serious manpower problems, the above-mentioned options should be explored to ensure that a SPIRou-like instrument will be available at CFHT within a reasonable time scale.

Recommendation 5: alternatives to SPIRou

SAC recommends that CFHT explores alternative options to SPIRou to obtain an IR spectropolarimeter for CFHT. In particular CFHT is encouraged to communicate with the UPF team.

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SAC took note of the fact that the completion of the phase A study of SPIRou has now been postponed for examination during the November 2010 SAC meeting. SAC needs to have all documents ready by October 1 to allow enough time for an external review. Meanwhile, given the possible competition/complementarity/merging option with similar instruments, SAC wishes to have some rapid clarification on the scientific goals of a CFHT spectro(polari)meter, depending on its capabilities (spectral resolution, near-IR coverage up to the K band, polarimetric option).

Recommendation 6: Science cases with spectropolarimeters

SAC recommends that documents clearly describing the science drivers of SPIrou and alternate IR spectro(polari)meters be ready for the SAC meeting to be held in Spring 2010. A comparative study summary sheet of the various IR spectro(polari)meter options should be presented to SAC which make it clear which science cases require which capabilities.

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The `Imaka team provided SAC a comprehensive interim feasibility report, which included the following key elements: an exploration of various optical designs, a study of the local optical turbulence at CFHT and performance simulations taking into account the major error terms. Most of the efforts of the team focused so far on the two latter aspects, while the preliminary study of the optical designs has been entrusted to external optical designers. Several possible designs were already received and briefly presented in the interim feasibility report. Some of them propose solutions without an adaptive secondary mirror - an expensive option as noted in previous reports. Alternative designs based on collimator/pupil imager plus refractive cameras at either the Cassegrain or prime focus seem possible. Furthermore one of the major targets of `Imaka - a 1.0 degree diameter field - now appears feasible, whereas doubts about it had raised at the time of the last spring SAC meeting.

The turbulence within the dome has been measured during ESPaDOns QSO nights with an optical turbulence profiler (OTP) deployed at the bent-Cassegrain port. A series of wavefront sensor images of a bright star over a 15 minute period were obtained. These observations confirmed the high level of dome-induced turbulence that is also put forward in the papers by Salmon et al. and Racine et al.

The OTP campaign and updated performance simulations allowed to compute, among other key elements, the probability distribution of `IMAKA image quality. With the GLAO-only system (i.e. without considering the gain by the OTCCD correction), the gain is of around 0.3 arcsec "whatever" the external seeing. The goal of 0.3 arcsec seems to be reachable at the reddest wavelengths at least 20% of the time. The sky coverage, driven by the requirement of guide stars for the OTCCD correction, is estimated around 40% at the NGP. The document lists many more error budgets. One challenge will be to transfer all these numbers in a comprehensive though practical way to the science team. This has not yet been done. Meanwhile the OTP campaign will continue and the installation of a "true" profiler (SLODAR instrument) able to directly determine the turbulence altitude is planned for 2010.

SAC is impressed by the work done so far on the technical side and congratulates the `Imaka team and CFHT for this achievement and for having been able in a few months to increase the community engagement. The re-assessment of the science cases complying with the updated instrument performance is now a priority.

Recommendation 7: science with `IMAKA

SAC recommends that the 'IMAKA team presents a reassessment of the science case based on updated expectations of the instrument performance; in particular the evaluation of which science goals require a given field of view, IQ distribution across the field of view, and for what fraction of the on-sky time given IQs would be available.

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Both the science and technical documents should be sent by SAC 2 months in advance of one of its future meetings (May 2010 or Nov 2010) so that it may be sent to an external reviewer. The cover letter of the interim feasibility report states that the complete feasibility study should be completed by the 2010 spring meeting. At this stage and given the lack of urgency, SAC does not however require any firm deadline. Having solid scientific and technical studies should be the main priority.


SAC received from the SITELLE team a letter summarizing the current financial status of the project. A grant of $2.2M (Canadian) was allocated from the Fonds canadien de l'innovation (FCI, or CFI in English) to build an imaging Fourier transform spectrometer. Compared to the estimate of the total cost of the instrument there are still funds that are not yet identified. A proposal has been submitted to the French agency INSU, requesting a contribution toward the unidentified funds.. The SITELLE team has contacted CFHT for an additional monetary contribution.

The phase A study of SITELLE will start as soon as the FCI money has been received. If everything goes according to schedule, the instrument could start operations in 2013A.

Since the approval by the board of SITELLE as a possible guest instrument, contacts have been taken with the French community. Discussions have started to explore the capabilities of SITELLE to contribute to the ground based spectroscopic follow-up of Gaia.

SAC acknowledges the interest of expanding the scientific goals of SITELLE (so far considered as a niche instrument for studies of the ISM in the Galaxy and nearby galaxies) and notes that the instrument may exploit a favorable slot in the telescope scheduling.

Recommendation 8: CFHT support to SITELLE

SAC recommends CFHT be allowed to put limited manpower and financial support into SITELLE, with the goal of the instrument being ready in 2013.

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SAC received from GEPI (Observatoire de Paris) a preliminary feasibility study for a wide field of view spectrograph with high spectral resolution (15,000-30,000) and multiplex capabilities (of order 500 fibers), called Gyes. The main global objective is to ensure the scientific throughput of the astrometric space mission Gaia. Gyes would conduct a survey of about one million stars, for which Gaia would have already obtained proper motions. It would provide radial velocity measurements at 1 km/s for stars down to magnitude 18 (instead of 13 for the RVS spectrograph on board Gaia) and detailed elemental abundances for stars brighter than magnitude 14 (instead of 12 for the RVS). The scientific aims would be the same as that of Gaia: the understanding of the structure, origin and history of our galaxy.

A similar high spectral-resolution instrument planned for the AAT, HERMES, may contribute to the ground-based follow-up of Gaia. However, HERMES data will not be directly available to the French Gaia community, meaning that some major science from Gaia cannot be exploited.

In the northern hemisphere, wide field of view and extreme multiplex spectrographs are also planned, such as Big Boss at the KPNO 4-m telescope or XMS for the Calar Alto 3.5m telescope; the latter instrument is based on the MegaMOS concept examined by SAC in 2009. Their low spectral resolution (which complies with the cosmological objectives of these instruments) would not allow the precise chemical measurements needed by (part of) the Gaia community.

The need for a Gaia follow-up instrument accessible to the French community has arisen very recently, and was extensively discussed during the INSU prospective days. A team with a PI at GEPI quickly gathered and built up an already-solid preliminary feasibility study for a fiber-fed spectrograph. The instrumental concept is claimed to use only proven technology, either already developed at GEPI or in the lab of a partner for the challenging fiber positioner. A proper phase A study will tell whether this is really the case and whether the installation of the instrument in 2015, at the time of the first Gaia data release, is realistic. A proposal to finance this phase A study has been sent to INSU. If accepted in early 2010, the study may be completed before the November 2010 SAC meeting. The science team will meanwhile contact Canadian scientists who may be interested in the project.

At this stage, and given the lack of precise information on the scientific objectives of Gyes, SAC finds it to be too premature to state a formal recommendation on this instrument. However SAC will be ready to examine a phase A study (funded by INSU) which should include a detailed scientific rationale. All documents should be sent by October 1/2010 to allow enough time for an external review. SAC strongly encourages CFHT to provide the Gyes team all information required to carry out the phase A study.

4. Telescope use and scheduling

Trends in telescope/instrumental use

Despite the end of the CFHTLS and the fact that the current LPs currently occupy less than 40% of the available time, the pressure on PI time has been relatively high for the 2010A call for proposals. The Canadian agency had a pressure slightly above 3 for 2010A proposals. For the French agency, after having significantly dropped during the previous semesters, it reached in 2010A a level of 1.9.

The national TAC members at SAC still feel that only high quality programs are scheduled at the telescope, and that there are good proposals that are not getting allocated.

A noteworthy trend is the higher request for WIRCam. This is partly due to the need to now carry out near-infrared follow-up of MegaCam optical surveys. In addition, the opening of the steering/fast-readout observing mode has opened an avenue for new scientific programs (which however do not usually require the large field of view of WIRCam). This mode has been requested by several proposals in 2010A.

Queue Service Observing

Daniel Devost presented SAC the traditional QSO report for the period 2009A. MegaCam and WIRCam programs were badly affected by poor weather conditions. The B completion rate was only 46% for MegaCam and 43% for WIRCam (and was 93% and 94% for A programs, respectively). Although more tolerant to bad sky conditions, ESPaDOnS was affected as well. Only 2 of the 14 started programs could be fully completed.

Following the Nov 2009 meeting, SAC investigated these low completion-rates for 2009A ESPaDOnS programs. Of these, only one in the A/B category is a monitoring program where the science may have been dramatically affected. While the system merits continued vigilance, at this stage SAC feels no action need be taken.

Hours/night estimation

Given the poor weather statistics in the last winter semesters, the number of hours / night conversion factors, which have not been changed for a while, might have to be revised to more reflect the reality.

Recommendation 9: hours - night factor

SAC recommends that CFHT continues to monitor the average number of  hours per night typically available to each instrument and update  their hours per night calculation accordingly.

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To fulfill the need of one MegaCam Large Programme, the NGVS, Jean-Charles Cuillandre, as a NGVS CoI, developed a new processing pipeline, known as Elixir-LSB. The pipeline was thoroughly tested by the NGVS team and has already been adopted by one regular PI program. This processing pipeline handles a proper sky subtraction on the optical images (with an observing/reduction technique similar to the one traditionally used for IR observations) and allows the detection of Low Surface Brightness features which with a classical Elixir processing would be hidden by the scattered light of MegaCam. Elixir-LSB would be most valuable to any PI whose programs use an NGVS-like observing strategy. Jean-Charles Cuillandre and Christian Veillet propose to offer this service to the community.

Recommendation 10: Elixir-LSB

SAC recommends that CFHT proceed with the plan to make Elixir-LSB available to PI programs whose observing policy   benefit from the real-time background determination that Elixir-LSB provides.

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Rough stacks of Elixir-LSB images will be made locally at CFHT to control the quality of the data processing. Science quality stacks will still be made by Terapix or MegaPipe.

Discretionary time in 2009

SAC was presented the list of proposals that obtained Director Discretionary Time in 2009. Christian Veillet indicated that only about half of the allowed D-time has been used. The unallocated nights were given back to QSO.

Engineering time in 2010A

As noted before, no engineering nights will be devoted to AOB activities in 2010A. The 11 scheduled engineering nights will mainly be used for the training of the staff with remote observations, instrument setups, CCD upgrade of ESPaDOnS and the seeing measurement campaign. The decision to re-aluminize the CFHT mirror in 2010 is pending.


As chair of the CFHTLS Steering Group, Jean-Charles Cuillandre presented SAC with the report of the Legacy Survey, which completed observations one year ago. The official release of the T0006 data, which includes all the Deep + Wide data, has been announced a few days before the meeting of SAC. It was accompanied by a comprehensive technical document on the content of the release. T0006 consists of 5 Tb of data and includes an impressive set of 2100 images and 2200 catalogues.

The "final" T0007 release planned next year will in principle include a revised photometric calibration (after a re-processing of all images with Elixir to take into account new calibration recipes) plus the Very Wide data, which have not yet been officially released by Terapix.

Since the T0006 and T0007 releases will basically include the same set of images, SAC encourages the SG to communicate to the community about the expected differences between the two releases. Indeed some scientific goals might benefit from the increased photometric accuracy provided by T0007 while others might not need it.

Pierre-Alain Duc reported to SAC complaints received from some French CFHTLS users on the slow data access to the CFHTLS products hosted at CADC. A general poll to the CFHTLS users community made just before the SAC meeting received a few answers, mainly from France, and indicated transfer rates strongly varying from one institute to the other but that were indeed generally poor: from 0.5 to 5 Mb/s. In some institutes, transfer rates from CADC appear to be poorer than to other data servers (although no detailed information on where these other servers were was presented to SAC). On its side, CADC has already started to study these putative connection problems and a network specialist is pursing the issue. An initial investigation presented in a recent NGVS consortium meeting and to SAC showed that the fastest connections (with transfer speeds exceeding 50 Mb/s) were obtained from a bunch of about ten Canadian institutes, suspected to have very good connection to the national backbone, while many other Canadian institutions report rates similar as the French institutes. The problem appears to be network connectivity between CADC and the destination, rather than CADC's ability to push data out onto the backbone. The transatlantic connection, or local connectivity of the institutions to their national backbone, is the likely weak point.

SAC discussed the situation. It was pointed out that, while downloading terabytes of data with connection rates of a few Mb/s may be painful, the F+C users aware of the content of the CFHTLS products and really interested in obtaining the full CFHTLS dataset may find alternative solutions than network transfer: for instance, having the data burnt on disks and sent by regular mail may take less time! SAC is more worried about the possible discouragement of new or occasional CFHTLS users that would like to have a first look at the data without having to wait too long to mine them. Ensuring a decent data access to CFHTLS products at the time of the world release will contribute to the success of the survey.

Data access problems are usually dealt with by creating mirror sites. One natural institute to host such a mirror in France is the Centre de Données de Strasbourg (CDS). Christian Veillet reminded SAC that the MoU between CFHT, Terapix and CADC which set CADC as the “primary” responsibility for distributing the CFHTLS products does not prevent the existence of secondary servers. As a matter of fact, CDS attended the initial CFHTLS meetings at the beginning of the survey. It recently expressed its desire to at least be able to distribute the catalogs. Technical solutions should probably exist to keep at CADC the control and census of the data access, while the data may physically be located elsewhere.

Recommendation 11: accessibility of CFHT LS data.

SAC recommends that CFHT, CADC and CDS work together to investigate  the merits and practicality of providing a French mirror site to  improve the accessibility of CFHT-LS data.

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Reports from on-going Large Program

SAC received progress reports for each of the four new CFHT Large Programmes. In general, they are progressing well. Data of high quality are being obtained. The help provided by the CFHT QSO team is greatly appreciated by the PIs. Information within the collaborations circulate via dedicated web pages and regular meetings. First publications showing results of the LPs have already appeared. In details, each LP has its own characteristics and requests to CFHT and SAC.

MaPP has generally benefited from rather collaborative weather conditions; the monitoring campaign of one target planned during an ESPaDOnS run especially scheduled to comply with the MAPP needs had to be abandoned due to poor weather. A request to CFHT to compensate for the “lost” time by scheduling an alternative star was discussed at SAC.

MiMeS already achieved the detection of magnetic field in 5 new OB stars, i.e. more than anticipated. As a result, the time dedicated to the follow-up monitoring of these stars has already been used. Whether because of this success, part of the program should be de-scoped or whether additional PI time should be requested through national TACs was discussed by SAC.

PAndAS can for various reasons already claim success. Due to good weather conditions in B semesters and the absence of competing PI programs at its RA, the observations are ahead of schedule: part of the time allocated for 2010B will already be used in 2009B. Two papers were already accepted. One published in Nature revealing the past collision between Andromeda and M33 received considerable attention.

NGVS reports obtaining data of superb quality. Thanks to an updated observing strategy and the development made for the data reduction (Elixir-LSB), surface brightness levels fainter than anticipated (29 mag/arcsec2 in the g band) have been obtained. Unfortunately this LP was much less lucky than the others with the weather and the NGVS report claims some penalty due to competition with PI programs. The net completion rate for the 2009A observations was only 61.1% (for the A+B time). As a consequence, the project was forced to de-scope the survey and chose to entirely drop the r-band coverage of the cluster. While the resulting negative impact on the Virgo science is acceptable, the lack of r-band coverage severely compromises the high-redshift component of the survey.

Discussion of LP vs PI competition

SAC was presented with several proposals by the NGVS PI in the progress report, aimed at maximizing the completion of this single-RA large program. SAC also extensively discussed a letter from the Canadian TAC asking for clarification on LP vs PI competition which under specific circumstances might disfavor the latter. During the discussion of LP vs PI programs, the four SAC members involved in LPs left the room. Likewise, the two SAC members involved in the NGVS recused themselves when the SAC discussed the NGVS-specific requests.

SAC considered these two requests to re-evaluate the balance of LP vs PI programs. The low completion rate (especially the low 41% figure for B-class OGs of NGVS) was agreed to be dominantly due to poor weather in 2009A, especially during the dark runs optimal for the NGVS large program. The issue of how PI programs might compete against large programs was discussed, and it is confirmed that Agency balancing is the primary mechanism by which CFHT determines priorities within the queue system. Based on discussion of a letter from CTAC to SAC, SAC proposes a mechanism whereby the national TACs can choose to set priorities between existing LPs and PI proposals that conflict with the observing conditions of LP OGs. This puts the responsibility for managing these conflicts directly on the national TACs, along with the obligation of dealing with conflicts of interest of TAC members who are on the LPs.

Recommendation 12: LP vs PI competition

Beginning with the proposals submitted in the March 2010 round, when CFHT performs its technical evaluation (which is then communicated to the TACs), CFHT will flag any proposal which has conflicts in RA and observing conditions with an existing LP.  During their ranking process, the national TACs which are participating in both the conflicting PI programs and LP(s) will provide information to CFHT on the relation and priority of each of those, although agency balancing will continue to be the first decision point for CFHT.
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The future calls for regular/LP proposals should inform the community about these changes in procedure .

Next call for Large Programs

The answer to the call for letters of intents for new Large Programs was a success. CFHT received 10 LoIs whereas with the current maximum 40% cap, at most 3 (likely 1 or 2) new LPs may be scheduled. Most (7) of the programs asked for WIRCam, 2 for MegaCam and only 1 for ESPaDOnS. All LoIs respected the scheduling restrictions stated in the call and therefore none of them were excluded for the coming formal call for LP proposals which should be issued by the end of November. As intended, SAC did not discuss the scientific aspects of the LOIs.

Given the high number of proposals to be reviewed, SAC re-discussed the procedures for the time allocation. SAC recommends that the LP-TAC consist of 3+3 members that are currently serving or have recently served in the French / Canadian TACs. The LP-TAC members should be proposed by the chairs of the national TACs among those that declare not to have any conflict of interest with the programs proposed in the LoIs. The two chairs should interact with each other to ensure that the fields of science covered by the new LPs have experts in the committee. Names should then be approved by each national agency. The LPTAC will then meet between the deadline (February 1st) and the Spring SAC meeting.

The responsibility of the LPTAC will be to:

  • rank the 10 proposals
  • comment on the time share  between Canada/France. The CFHT TAC will take the final decision.
  • evaluate the scientific quality of the top proposals which may be scheduled relative to the quality of recent highly ranked PI proposals. This information will be used by SAC in its evaluation of the need to keep a 40% limit to LPs.

SAC will then be responsible for setting the cutoff line at 0 or more proposals. If needed, SAC may recommend an expansion of the 40% figure, to be approved by the Board in June 2010 in time for the start of the observations in August 2010.

Since several SAC members are coIs of the LoIs received by CFHT and have had therefore access to the full list of proposals, SAC suggests that the titles and abstracts of all proposals are sent to all LoI PIs, after having asked their authorization.

5. Future of CFHT

Christian Veillet provided a brief update on the Golden Age plan, presented SAC with the recommendations of the INSU prospective exercise regarding the future of CFHT, and evoked the likely future of Mauna Kea if the TMT is installed in Hawaii.

6. Next SAC and Users' meeting

Next SAC meeting is scheduled to take place 10-11 May 2009 in Vancouver. The user’s meeting will take place in Taiwan 15-17 Nov 2010 and will be followed by the SAC meeting. As a consequence no visit of SAC to Hawaii is planned in 2010. The program of the Users Meeting will be discussed through email exchanges in the coming months.