CFHT Community Survey

Call for Proposals

Key Steps and Dates:

  • Submission of optional, but encouraged, non-binding Letters of Intent (LOIs):
    • Deadline: December 1, 2025, 23:59 UT
    • Send an email to cswg-info@cfht.hawaii.edu
  • Proposal submission:
    • Deadline: April 30, 2026, 23:59 UT
    • Submit your proposal on Kealahou

As outlined in its 10-year plan, the Canada-France-Hawai'i Telescope (CFHT) is opening 800-1400 nights, nominally over a 6-year period (2027B-2033A) for a Community Survey (CS); the starting semester and length of the CS may be adjusted to optimize its scientific return. The CS will not be carried on beyond 2033B. This survey is designed to serve the entire CFHT community and to generate datasets of lasting scientific legacy value.

The National Research Council of Canada (NRC) and the Centre National de la Recherche Scientifique (CNRS, France) are contributing up to 85% of their agency time for the Community Survey. The University of Hawai'i (UH) may participate on a proposal-by-proposal basis. For more details regarding UH's participation, please refer to this page.

The definition and organization of the Community Survey is coordinated by the Community Survey Working Group (CSWG), based on community input provided in response to this call. A full member list of CSWG is included in the menu at left. Interested teams are encouraged to reach out to any CSWG members or to contact cswg-info@cfht.hawaii.edu with questions.

The purpose of the LOIs is twofold. Firstly, LOIs will help foster synergies between teams with overlapping goals, while final proposals will undergo external peer review and may be consolidated into CS teams coordinated by the CSWG. Secondly, any update available (e.g., the number of nights available) before the deadline will be communicated to the people listed in the LOIs.

To support teams during the proposal preparation stage, a FAQ page (also see menu at left) has been created and will be maintained throughout the submission process, as well as news for this proposal process. Teams that submit LOIs will be notified whenever new entries are added to the FAQ page.

Table of Content

  1. Community Survey Definition
  2. Optional Non-binding Letters of Intent
  3. Time Available
  4. Instruments Offered
  5. Content of a Community Proposal
  6. QSO Mode and QSO SNR Mode
  7. The Completion of Community Survey
  8. Proprietary Period and Data Access
  9. Data and Project Management Plan
  10. Support Offered to the QSO Team by CS Teams
  11. Additional Technical Details
  12. Submission Deadline April 30, 2026
  13. Selection Process and Rubrics
  14. Timeline
  15. Community Survey Working Group

1. Community Survey Definition [Back to Table of Content]

CFHT is allocating 800 nights (minimum) up to 1400 nights (maximum) over a 6-year period (2027B-2033A) to conduct a Community Survey.

The CS is expected to consist of two ambitious observing programs, one for each instrument:

  • A high-resolution spectroscopic or spectropolarimetric program using Wenaokeao that allows for simultaneous - or independent - observations using ESPaDOnS and SPIRou. This program will be allocated 400 - 700 nights (7 hrs/night) and use predominantly bright/grey time in ~2-week blocks per month that spans all RAs and a broad range of observing conditions.
  • An imaging program using MegaCam. This program will be allocated 400 - 700 nights of time (5 hrs/night) and use predominantly dark/grey time in ~2-week blocks per month that span all RAs and a broad range of observing conditions.

SITELLE and WIRCam are not offered.

Teams proposing new MegaCam filters or additional instrumental functionality must contact the Director of Science Operations (manset@cfht.hawaii.edu) prior to submission.

To maximize the scientific return of the Community Survey, proposals are expected to integrate multiple work packages with diverse science goals. Although interested teams may request a fraction of the maximum nights available, and synergy between multiple proposals for MegaCam or Wenaokeao may occur after the review stage, we strongly recommend that teams proposing for the same instrument engage in early conversations and explore possible synergies before submission (see Section 2 for more details). This approach will help ensure that the proposed program makes full use of the available nights and reflects the breadth of scientific interests within the CFHT community.

Following the review of submitted proposals in Spring-Summer 2026, one or multiple proposals per instrument may be selected and/or consolidated. The resulting Community Survey teams (one for MegaCam and one for Wenaokeao) based on the proposals received will then be formed under the coordination of the CSWG, which will oversee this process in consultation with the community. Each CS team will establish a steering group, which will be responsible for the 6-yr survey operation and coordination. Membership in the CS teams will be open to all Canadian and French community members at any time via application to the steering group.

2. Optional Non-binding Letters of Intent Due December 1st, 2025 [Back to Table of Content]

To promote coordination and synergy, the CSWG will organize town hall meetings in December 2025 or January 2026. These will connect groups with overlapping scientific goals and help consolidate strong, unified Community Survey proposals.

To support this process, teams are strongly encouraged to submit a Letter of Intent (LOI) by December 1, 2025 (23:59 UT) to cswg-info@cfht.hawaii.edu.

LOIs should be concise (~100-200 words, in an email or as PDF attachment) and include:

  • Brief science goals
  • Instrument(s) and setting (e.g., filters for MegaCam, polarimetry or spectroscopy for Wenaokeao)
  • Estimated hours and acceptable Moon illumination in % (dark nights have an illumination <50%, bright nights have an illumination >50%)
  • Keywords (using one or more keywords from K1: High Z universe, ISM CSM PNe and star formation, low z universe, Solar system and exoplanets, stars and stellar populations, time domain astronomy)

The LOI is not required but highly recommended if you wish to coordinate your proposed program as part of a large, synergized program for the CS. Their purpose is to inform CSWG of potential participants and facilitate collaboration through the town hall events. An acknowledgment of receipt will be sent within 2 business days. Information submitted in LOIs will be shared with other teams; the WG will put all MegaCam teams in contact with one another, and all Wenaokeao teams in contact with one another. Furthermore, any update before the deadline will be communicated to the people listed in the LOIs.

3. Time Available [Back to Table of Content]

Up to 800 nights (400 nights for each instrument) over 6 years are available, with a possibility of expansion to 1400 nights (700 nights for each instrument).

As the total number of nights to be allocated is not yet finalized, proposals must present science goals and survey plans that would be met with ~400 nights (or fewer), and additional results that would be enabled by utilizing an additional ~300 nights (700 nights maximum per instrument).

Teams should note that MegaCam will primarily be scheduled during dark time (Moon illumination <50%), with a maximum of approximately 90 nights per semester. Wenaokeao (ESPaDOnS + SPIRou) will typically be scheduled during bright time (Moon illumination >50%), also up to approximately 90 nights per semester. To minimize workload for CFHT operations, instruments are expected to be swapped about every two weeks: roughly two weeks of MegaCam in dark time, followed by two weeks of Wenaokeao in bright time, and then back to MegaCam. If a program requires a different cadence or specific Moon phases, a clear justification for such special arrangements must be provided in the proposal.

Proposals have to use the following conversion for the number of hours per night for each instrument (including both the open shutter time plus overheads). For more details on weather, image quality, and variations over time, please consult the Weather and Sky page.

  • MegaCam: 5.0 hours/night
  • Wenaokeao (ESPaDOnS+SPIRou): 7.0 hours/night

These numbers are based on historical values over the last several years. These numbers correspond to averages over the full range of usable observing conditions and right ascension and assume that MegaCam observations typically start and end at the 12-degree twilights, while Wenaokeao observations typically start and end at the 8-degree twilights. The time requested in a proposal shall be in hours, and the final allocation of an accepted CS will be in nights using the conversion above.

4. Instruments Offered [Back to Table of Content]

Teams are encouraged to read the documentation related to the instrument(s) they plan to use. Exposure Time Calculators are also available and must be used to calculate the number of hours requested.

Instrument Webpage ETC Instrument Scientist
MegaCam MegaCam DIET Heather Flewelling flewelling@cfht.hawaii.edu
ESPaDOnS ESPaDOnS ETC Nadine Manset manset@cfht.hawaii.edu
SPIRou SPIRou ETC Luc Arnold arnold@cfht.hawaii.edu
Wenaokeao Wenaokeao Nadine Manset manset@cfht.hawaii.edu
Luc Arnold arnold@cfht.hawaii.edu

Wenaokeao (previously known as VISION) is an optomechanical interface that enables simultaneous use of SPIRou and ESPaDOnS at the Cassegrain focus. The Community Survey will be designed to use Mode 3 (simultaneous SPIRou + ESPaDOnS observations). Modes 1 (SPIRou only) and 2 (ESPaDOnS only) may be available if Mode 3 is not suitable due to technical limitations and should be justified in the proposal.

Wenaokeao requirements state that the maximum acceptable level of polarimetric contamination / crosstalk induced by the optics shall be:

  • from Stokes I (unpolarized) to Stokes Q, U and V (linearly and circularly polarized light) spectra: 0.01%
  • from Stokes Q and U to Stokes V spectra (and vice versa): 1% (as typical Stokes QUV signatures in spectral lines very rarely exceed amplitudes of 1%)
  • from Stokes Q to U (or vice versa), crosstalks are not an issue if within 10%, and can be compensated for by a small rotation of the instrument and / or through the observation of standard stars.

If a team proposing an ESPaDOnS program has concerns regarding the performance of Wenaokeao in Mode 3, they shall provide details of those concerns and the appropriate levels of contamination or crosstalk acceptable.

5. Content of a Community Proposal [Back to Table of Content]

The proposals must contain:

  • A Scientific Justification: up to 5 pages + 3 pages of figures. References are included in a separate section and do not count toward the 5 + 3 pages limit. The Scientific Justification must include:
    • A description of the primary science goal(s) that correspond to the minimum number of nights requested (up to 400 nights),
    • A description of the secondary (and tertiary) goal(s) that correspond to the additional science that could be performed if the allocation reaches the maximum number of nights requested (up to 700 nights) and/or auxiliary science goal(s) achieved with the twilight time (see details in Section 3),
    • A description of the potential legacy value of the proposed observation,
    • For Wenaokeao: the scientific impact of simultaneous ESPaDOnS+SPIRou observations.
  • A Technical Justification: up to 8 pages. The detailed requirement for the Technical Justification can be found at this link.

6. QSO Mode and QSO SNR Mode [Back to Table of Content]

The CS will be executed under the QSO mode. In addition, it is assumed that the CS will take advantage of the QSO SNR mode. If the QSO SNR mode is not suitable, the team must justify it in their proposal.

7. The Completion of Community Survey [Back to Table of Content]

If the primary science goals of the proposed Community Survey are not achieved within the six-year period, a finite number of nights in semester 2033B may be allocated to the CS team, subject to approval by the CFHT SAC and Board, to support the survey's completion. Beyond 2033B, no further extensions will be granted, given the current uncertainties regarding the future of the CFHT site.

8. Proprietary Period and Data Access [Back to Table of Content]

Members of the Community Survey (CS) teams will have immediate access to both the raw data and the nightly processed data through the CADC. Membership in the CS teams will be open to all individuals from the Canadian and French institutes, who may join at any time by submitting an application to the steering group (once it is formed after the review process). Importantly, there will be no possibility of rejection for such applications. For members of the University of Hawai'i observing community, access will be limited to those who have received CFHT time on an accepted UH Community Survey contribution dedicated to supplementing UH time in one or more of the CS programs.

The nightly processed data are detrended to remove instrumental signatures using biases or dark, and flat exposures. For MegaCam exposures, an approximate astrometric and photometric solutions are computed. The images are not stacked. For ESPaDOnS and SPIRou exposures, the pipelines perform the wavelength calibration and polarization calculations as well as first-level telluric correction. Spectra are not co-added.

The plan for accessing high-level, value-added data products will be determined by each CS team and described in detail in the Data and Project Management Plan. In keeping with the spirit of a community survey, it is expected that value-added products will be shared within the CS teams at a frequency of one to two times per year. These high-level data products should then be released to the international community no later than one year after the completion of the survey.

For the metadata information (e.g., target name and coordinates), the default is for the metadata to be public and available immediately via the CADC. The PI may request, with justification, a delay in exposing the exposure metadata at CADC.

Proposals must explicitly state the desired duration of data protection (proprietary period). This duration may vary during the execution of CS (e.g., a longer proprietary period for the first years of the survey) and, if desired, depending on whether the data are raw and corrected for instrumental signatures or advanced data products. Specific situations requiring immediate release (e.g., transient objects requiring follow-up observations with other facilities) should be described in the proposal. This will inform the policy for making data publicly available, which will be approved by CFHT's Board.

9. Data and Project Management Plan [Back to Table of Content]

The proposal shall include a Data and Project Management Plan as part of the Technical Justification of the proposal. The Plan shall include information or requirements affecting CFHT (see FAQ), work to be performed by the CS team, and availability of value-added data products.

Details of the work to be undertaken by the CS team shall include a clear data-analysis plan, a description of the available resources, and evidence of the team's capability to carry out data reduction. The plan should also specify proposed proprietary periods for raw data and metadata, as well as any other considerations relevant to the handling or use of the data and targets. Examples include the development of a publicly accessible and queryable database, identification of the hosting data center, provision of documentation and visualization tools, and the inclusion of potential education and public outreach components within the CS.

The CSWG will look favorably upon proposals that commit to the timely public release of value-added products, such as carefully calibrated processed data, catalogs, and databases. These products should be made available to the CS community on a regular schedule and released to the broader community within the timelines outlined in Section 8.

Teams are strongly encouraged to contact JJ Kavelaars (JJ.Kavelaars@nrc-cnrc.gc.ca) to discuss opportunities for collaboration with CADC and CANFAR. Any planned collaboration with CADC, CANFAR, or other data centers must be explicitly described in the proposal.

10. Support Offered to the QSO Team by CS Teams [Back to Table of Content]

CFHT requires Community Survey (CS) teams to indicate how they intend to provide support for CFHT's operations and observations, and to specify the level of resources they are prepared to commit. Such support can take many forms, including but not limited to the following possibilities, in order of priority from high to low for CFHT:

  1. CS teams are highly encouraged to provide on-site scientific personnel, either part-time or full-time, to assist in survey execution and/or CFHT scientific operations such as queue coordination (highest need) or data reduction. Limited CFHT funds are available to help cover travel expenses (plane tickets, visa costs) and to provide lodging assistance for students or visitors who are able to stay on site for 6-12 months. Graduate students or post-docs in particular may take advantage of this opportunity to acquire hands-on operational skills. Contributors who excel and are committed to maintaining Hawaii hours may be allowed to work remotely from their home institute after an initial on-site training.
  2. CS teams will be required to provide, frequently during scheduled CS runs and/or at a time agreed with CFHT staff, a list of observation groups to be inserted directly into the QSO queues, complete with priorities, by updating the program information in Kealahou. This support is especially important for CS programs that involve long-term monitoring of targets.
  3. CS teams will be required to maintain an up-to-date record of CS execution in a format agreed upon with CFHT staff (e.g., a website or private wiki with tracking tables).

11. Additional Technical Details [Back to Table of Content]

The total time requested for either instrument must include the open shutter time calculated using the appropriate ETC and the overheads listed below.

For MegaCam, the overheads are 40s per exposure.

For Wenaokeao and for each target, the proposal must include the open shutter time and overheads for each instrument, and indicate which observation (ESPaDOnS or SPIRou) will take the longest time. When exposures time differ, only the longest observation will be charged and needs to be included in the requested time.

  • For ESPaDOnS, the overheads depend on the readout speed selected for each exposure: fast (20 sec), normal (20 sec), slow (33 sec).
  • For SPIRou, the overheads are 28s per exposure in spectroscopic mode, or 35s per exposure in polarimetric mode.

In addition, the total requested time must include any calibration not already taken by the QSO Team. For all instruments, appropriate instrumental calibrations are obtained (biases, darks, twilight flats, lamp exposures, fringe frames). Broad-band photometric standard stars and astrometric standard fields are also taken for MegaCam; no spectrophotometric standards are taken with ESPaDOnS or SPIRou. Narrow-band calibrations (for the imagers) must be included in the CS proposal.

Please take into account the following operational constraints:

ParameterLimit or constraintNote
MegaCam observationsbetween 12deg twilightsplease mention if observations need to wait for the 18deg twilight
ESPaDOnS and SPIRou observationsbetween 8deg twilightsplease mention if observations need to wait for the 12 or 18deg twilight
Hour angle limits+/- 5h30
Airmass limit for MegaCam 2.6722deg elevation limit
Airmass limit for SPIRou2.5recommended limit to ensure the Image Quality and quality of the guiding remain good, especially with SPIRou. The airmass constraint is less restrictive for ESPaDOnS.

12. Submission Deadline April 30, 2026 [Back to Table of Content]

Proposals must be submitted using Kealahou K1 after selecting the agency "Large Program". A tutorial for Kealahou is available online.

13. Selection Process and Rubrics [Back to Table of Content]

CFHT will provide the CSWG with the technical evaluation reviews of all submitted proposals, including feasibility assessments under normal observing conditions. The CSWG will then distribute the proposals for external peer review. Using both the technical reviews and the external peer review reports, the CSWG will rank all proposals according to the following criteria:

  • Scientific Justification (50%)
    • The scientific merit of the proposals, including the primary science goals as well as secondary, tertiary, and auxiliary objectives.
    • The risks associated with incomplete data collection.
    • The potential legacy value of the acquired data, including its utility beyond the main science goals of the CS.
  • Technical Justification (30%)
    • The completeness and quality of the required information for the technical justification (see list at this link), including (but not limited to): feasibility of the observations at CFHT, right ascension pressure, maximum usable Image Quality, acceptable extinction levels, airmass constraints, deviations from standard observing procedures (e.g., twilight usage, LSB mode), and monitoring cadence.
    • The quality of the data and project management plans (see Section 9).
    • The level of resources and support the team proposes to provide to assist CFHT operations (see Section 10).
    • Alignment with the technical details described above.
      Other Considerations (20%)
      • The willingness and ability of the CS team to synergize multiple science goals into a single, large, community-wide program — with preference given to proposals that demonstrate synergy or consolidation prior to submission.
      • The CS team's proposed plan to provide timely data access to the participating communities or to the full CFHT community.
      • The CS team's proposed plan to deliver value-added products in a timely manner via CADC or another recognized data center.

    In addition to ranking proposals, the CSWG reserves the right to adjust allocations by reducing or shifting nights from one semester to another if this optimizes telescope operations while still meeting the science goals. During the review and reconciliation phase, the CSWG may also consolidate and synergize multiple proposals into a single large program. Principal Investigators of affected proposals may be contacted as part of this process.

    The final recommendations from the CSWG will require approval by both the SAC and the CFHT Board before the Community Survey can begin.

    14. Timeline [Back to Table of Content]

    WhenWhat
    December 1st, 2025LOI deadline
    April 30, 2026Proposal Submission deadline
    April - August 2026External Peer Review process
    September 2026 - March 2027Reconciliation phase led by CSWG in collaboration with survey teams(s) to rationalize the outcome of the process with observatory/community constraints to ensure efficient and scientifically productive use of CFHT observing time
    April 2027Board final approval of the Community Survey
    May 2027Phase 2 (K2) opens for semester 2027B, for PI programs and the Community Survey
    Start of 2027BStart of the Community Survey

    15. Community Survey Working Group [Back to Table of Content]

    The Community Survey is organized and coordinated by the CSWG, composed of CFHT SAC members, CFHT staff representatives, and community representatives.

    If you have any questions, please send your inquiries to cswg-info@cfht.hawaii.edu . Alternatively, feel free to reach out to any CSWG members below:

    • Isabelle Boisse Isabelle.Boisse@lam.fr
    • Kenneth Chambers kchamber@hawaii.edu
    • Ryan Cloutier ryan.cloutier@mcmaster.ca
    • Jean-Charles Cuillandre jc.cuillandre@cea.fr
    • Stephen Gwyn stephen.gwyn@nrc-cnrc.gc.ca
    • Ting Li ting.li@astro.utoronto.ca
    • Nadine Manset manset@cfht.hawaii.edu
    • Mathias Schultheis mathias.schultheis@oca.eu
    • Antoine Strugarek antoine.strugarek@cea.fr
    • Gregg Wade gregg.wade@rmc.ca