QSO Phase1 MegaCam

u*, g', r', i', z' (Sloan set with a better and wider u)
the CFH12K filters H alpha ON, H alpha OFF, CN, TiO, O III. Note that those filters only cover the central 7x2 chips, with some vignetting on the edges of the field on the E and W edges of the mosaic.

For details about that instrument, please see its webpage. For additional questions, please contact Jean-Charles Cuillandre (jcc -=at=- cfht.hawaii.edu).

MegaCam is offered under the Queued Service Observing (QSO) mode only. The main concept behind the QSO scheme is to perform observing programs only during sky conditions or time constraints required to meet their science goals, as defined by the investigators. This can only be achieved if the programs are all grouped together in a database and are selected appropriately according to a set of constraints, rules and sky conditions. Programs are then carried out by a well trained, local team of observers in a service mode (i.e. investigators are not present at the observatory).

Before submitting a CFHT proposal, please read the short tutorial How QSO works at CFHT. [Keywords: QSO, Regular/TOO/Snapshot programs, Deadlines, NorthStar, Exposure Time Calculators, Technical Evaluations, TAC, Ranking, QSO grade, C programs, Snapshot programs, PH2, Observations, Sky conditions, Calibrations, Night Reports, Data reduction and distribution, Proprietary period, QSO rules, Contact information.]

Starting with 2010B, CFHT is using the NorthStar Phase 1 tool. NorthStar is used by Principal Investigators (PIs) to submit their proposal(s). All PIs must register as new NorthStar users; the registration page offers a Help file if assistance is needed. To make things easier, you may use your current PH2 login information as your NorthStar login information. The login information from NorthStar is NOT transferred to PH2. After login in, Help on how to use NorthStar is available on each page.

For technical information regarding MegaCam, please see the MegaCam page.

B - 2013B-specific information and news [Back to Table of Content]

Please note that during the semester 2013B, Large Programs are using the following RA ranges:

OSSOS on MegaCam : 70hrs for RA=0-4h
Matlas on MegaCam: 4hrs for RA=20-24h, 8hrs for RA=0-4h, 1hr for RA=4-8h, and 18hrs for RA=8-12h
Matysse on ESPaDOnS: 94hrs for RA=4-8h
Binamics on ESPaDOnS: 12.5hrs for RA=0-4h, 1h for RA=8-12h, 27h for RA=16-20h, 40h for RA=20-24h

For information about the relative priority of PI programs and Large programs, please see the recommendation from the SAC (Nov. 2009).

Note on non-sidereal tracking
The non sidereal tracking option (i.e., following a target with non-sidereal rates, but without guiding on stars) is offered, but the telescope shows drifts on exposures of 2-3min or longer. If you have questions or concerns related to this option for your proposal, please do not hesitate to contact the QSO Team (qsoteam -=at=- cfht.hawaii.edu).

Note on IQ measurement.
Image quality (IQ) on MegaCam images is measured in real-time during the observing by Elixir using the isophotal full width at half maximum (FWHM) using the SExtractor tool. This method provides a robust estimate over hundreds of stars across the field of view. This is the IQ metric used by the QSO team to evaluate and validate (or not) the exposures. Moffat profile fitting is not used for the validation since it is a slower algorithm, hence prone to larger errors due to the low numbers of stars used in the computation under the constraint of the real-time evaluation at the telescope. The isophotal FWHM metric typically delivers a conservative measurement of the IQ vs the Moffat fit (i.e. PIs measuring the IQ with a Moffat fit will obtain an apparent better IQ, 0.1" or so under median seeing conditions).

For Canadian proposals: the Science justification is now limited to 2 pages, and the Technical justification to 1 page. For all other agencies, the page limits are 3 pages and 2 pages respectively.

For more information about the submission of your QSO proposal(s), contact the QSO Team qsoteam -=at=- cfht.hawaii.edu.

C - NorthStar [Back to Table of Content]

NorthStar is the new Phase 1 tool to submit proposals. This tool is not Latex-based. The scientific and technical justifications, along with references and figures, are uploaded as PDF files, which may be prepared by the PIs on any software they may wish to use. Figures and references may be included with the Scientific and/or the Technical justifications.

Also note the following regarding the list of targets:

the list cannot be reordered by the user
the list is automatically reordered after each Save, based on a criteria other than name, RA, or DEC; moreover, CFHT does not have control over the final order of the targets
targets in excess of 15 are presented at the end of the proposal

D - Applicants [Back to Table of Content]

For each proposal, there can only be one submitter. However, co-I may be invited to view and edit the proposal too. The PI may also be different than the proposer (contact author). Note that if a proposal is accepted, it will get registered in PH2 under the PI's name, not the name of the contact author or the submitter! Each program belongs to its PI and requires the PI's login information in PH2.

E - Justifications [Back to Table of Content]

The Scientific and Technical justifications must be uploaded as PDF files, and have a limit of 2 and 1 page respectively for Canadian proposals, and 3 and 2 pages respectively for all other agencies.

Please use the MegaCam Direct Imaging Exposure Time Calculator (DIET) to calculate the exposure time for each of your target and justify the total integration time requested.

F - Observing Requests [Back to Table of Content]

For MegaCam, you may select QSO Regular programs or QSO Snapshot program. QSO Regular programs include all of the normal QSO programs, with fixed or Solar System objects. Target-of-opportunity (TOO) programs submitted at the same time as all other CFHT proposals may simply be submitted as a QSO regular program. Snapshot Programs must request bad sky conditions and accept a low completion level.

The definition of a snapshot program for MegaCam is the following:

A snapshot program describes valuable science to be obtained on targets observed only in the worse sky conditions (seeing larger than 1.2" in r band, and preferably during non-photometric conditions)
A snapshot program will be scientifically useful even of the completion is low
A snapshot program requests simple observations, preferably with the standard ugriz filters (narrow-band filters are possible too but are not always available), sidereal tracking, no monitoring
A snapshot program should preferably include short blocks of observations
The time allocated for such programs is not accounted for in the statistics of time spent for the different Agencies
The proprietary time for the data is 3 months following the end of the semester.

Note that the chance of such programs to be executed, even partially, during a semester can be quite high.

The probability of observing a specific program depends strongly on the image quality requested versus the statistics of the site. The chance that your program is performed is less if you request an IQ of 0.55" than if 0.8" is required. Of course, science should be the priority in your selection of IQ but beware that it cannot be the only criterion in your choice. So, do not request a better image quality than what is really needed for your program. For guidance, the table below describes the seeing statistics on Mauna Kea. These data are for the R-band and were taken with FOCAM at CFHT between 1993-1995 (more recent statistics confirm these values). Note that with MegaPrime we globally achieve about the same IQ distribution than with CFH12K, but not much better.

Image Quality (IQ)	Frequency
IQ 0.55"	5%
0.55" < IQ 0.65"	25%
0.65" < IQ 0.80"	30%
0.80" < IQ 1.0"	25%
1.0" < IQ 1.2"	15%
IQ > 1.2"	5%

For your information, the table below gives the average weather statistics for Mauna Kea. Note that the "A" semester is usually more affected by bad weather; time lost during the first few months of the winter can be as high as 50% and even more.

Sky Conditions	Frequency
Usable Nights	~70%
Lost to Weather	~20-30%
Usable Photometric Nights	~50%

In queue mode, the time requested is in HOURS.

If the total time of your program is fractional (e.g. 32.4 hr.), please indicate so (.4 hr in a queue mode is possible).
In your calculation of integration time, only add 40s of overheads for each exposure (for readout).
Slewing and acquisition of a guide star SHOULD NOT be accounted for in your calculations.
CFHT provides instrumental calibrations (e.g. flats) and photometric standard stars for the broad band filters only. Photometric standard stars for narrow-band filters, and any other on-sky calibration MUST be included in the proposal and in the time requested. The "Calibration Requirements" box may be used to present those calibrations.

Any time constraint or scheduling constraint must be indicated in the proposal: the need for a certain number of consecutive nights, the need for long blocks of time (for example, 8 hours) per night, the need to coordinate CFHT observations with observations taken by another telescope, etc.

By default, the proprietary period of QSO data extends to 1 year + 1 month starting at the end of the QSO semester. If an extension is requested and approved by TAC, a new date will be set for this program through the QSO system. The release date for the data is indicated in the fits headers by the keyword REL_DATE. For snapshot programs, the proprietary time is 3 months following the end of the semester.

G - Target list [Back to Table of Content]

Besides a list of targets with coordinates, MegaCam proposals may include the Magnitude of each target or the diameter of the field. This information will be used to evaluate the technical feasibility of each proposal.

H - Additional issues [Back to Table of Content]

The Additional issues tab is used to link various proposals together, if need be.

Z - Check list [Back to Table of Content]

Before submitting your proposal, please make sure that:

You have requested time in HOURS.
Your requested time includes the appropriate OVERHEADS: 40s for all exposures.
If your program is a Snapshot program, it requests bad sky conditions (bad Image Quality or extinction), is simple, and is made of short OGs.
You have included on-sky calibrations if needed and if not already taken care of by the QSO Team.
You have indicated the magnitude or diameter of your targets.
You have contacted the QSO Team for any question or concern.

Need More Information?
Contact the QSO Team at qsoteam -=at=- cfht.hawaii.edu