Service Observations with MegaCam
Phase 1 Proposal Submission Instructions
Updated Feb 16, 2016
|Table of Contents|
A - Introduction
B - 2016B-specific information and news
C - NorthStar
D - Applicants
E - Justifications
F - Observing Requests
G - Target list
H - Additional issues
Z - Check list
A - Introduction [Back to Table of Content]
MegaCam and the QSO mode
MegaCam is CFHT's optical Wide-Field instrument, offered with a new set of broad-band and narrow-band filters:
For details about the filters (list and characteristics, information about the ETC, current status of the calibrations, etc.), please see the official announcement.
For details about that instrument, please see its webpage. For additional questions, please contact Simon Prunet (prunet -=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.]
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 - 2016B-specific information and news [Back to Table of Content]
Please note that during the semester 2016B, Large Programs are using the following RA ranges:
For information about the relative priority of current LPs and the 2 new LPs, please see the recommendation from the SAC (May 2014).
NEW PH1 mandatory field
The PH1 system has been changed to have users include the values of the exposure time calculators into their proposals. Proposals cannot be submitted if this field is not filled. This is not counted toward the page charge.
NEW filter set, 40 CCD mode
MegaCam now has a new set of broad-band and narrow-band filters. All filters cover the 40 CCD (4 more chips than previously). For more information about the new filters, please see the official announcement.
REMINDER about Snapshot programs
All agencies are invited to encourage their community to submit snapshot programs. These programs must be able to accept an Image Quality worse than 1.2" or significant levels of extinction. Snapshot programs are used not only during bad weather conditions but also to fill gaps in the queues when no A, B or C program are available or suitable. Snapshot programs are not counted toward an agency's allocation.
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).
The exposure time calculator for MegaCam and WIRCam, DIET, have been merged together and now use a different interface, and different options. The ETC was also updated to include a galaxy profile mode. Please read the updated information about the new modes for point sources and extended sources. Note that between the most convervative (large aperture) and most aggressive (PSF photometry) modes, the exposure times for the same SNR vary by more than a factor of 3. Be sure to know what type of SNR you are requesting! Please present in your Technical justification the details of your exposure time calculations.
The new galaxy profile mode was added to the previous point-source and extended source modes. This new mode corresponds to galaxies more extended than a point-source, but where the seeing still matters. The galaxy profile itself is based on Sersic profiles with indices varying from 1 (exponential disks) to 5 (4 corresponds to de Vaucouleurs. profiles, typical of elliptical galaxies). The width of this profile is settled by the half-light radius, given in arcsec. The galaxy profile is then convolved with the seeing profile to make the exposure time or signal-to-noise ratio computations. This new feature is intended to replace the .galaxy" choice in the previous ETC. For larger galaxies where the seeing does not matter, you can either use the galaxy mode with a large half-light radius, or the extended source mode if you plan to reach a given surface brightness in the outskirts of the galaxy.
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 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:
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:
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
|Image Quality (IQ)||Frequency|
|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.
|Lost to Weather||~20-30%|
|Usable Photometric Nights||~50%|
In queue mode, the time requested is in HOURS.
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:
Need More Information?
Contact the QSO Team at qsoteam -=at=- cfht.hawaii.edu