Queued Service Observations

Table of Content

Current News and Events Pre-semester information During Observations Post Observations Information
News (Phase1 and PH2) QSO Observations Reduction
2015A Instruments Night Reports DADS
TOO Phase 1 Statistics Proprietary time
Contact PH2 TOO Archived information

Current News and Events [ Return to top ]


PH2 for semester 2015B is now closed for most programs.

Sitelle has arrived at CFHT! The first on-sky tests were successfully performed July 6-7-8, starting with focus, pointing, and simple observations through all the filters.

You may request information at any time by emailing qsoteam -=at=- cfht.hawaii.edu .

To obtain information on the progress of your program, please consult the QSO Night Reports

2015B schedule and programs

List of 2015B QSO programs for MegaPrime, WIRCam, and ESPaDOnS.

2015A information

List of 2015A QSO programs for MegaPrime, WIRCam, and ESPaDOnS.

QrunID Instrument HST Dates Number of Nights Status Run Summary
15AQ01 WIRCam Feb 01 - 11 11 Done An unusual amount of time was lost to high winds. About 100 hours, or the equivalent of almost 10 nights, were affected by high winds, or high humidity. A little less than one third of the 15A nights have been used, but only 6% of the hours in A and B-ranked programs have been validated.
15AQ02 MegaCam Feb 12 - 25 15 Done The first MegaCam run of the semester went relatively well. Three full nights were lost to weather, and the total amount of time lost to high winds, high humidity, and clouds was 50h. About 8 hours of sky time were used to calibrate some the new filters and to continue engineering tests for the new TCS.
15AQ03 ESPaDOnS Feb 26 - Mar 15 18 (originally 12) Done The winter weather has prevented observing for the majority of the run. The equivalent of fewer than 2 nights was used to collect data until March 9. The winter weather prevented the staff from accessing the summit for a week and pushed the MegaCam exchange. Due to all the uncertainties regarding the weather, access, and condition of the summit facility, it was decided to keep ESPaDOnS until Mar 15/16. The summit facility became accessible Mar 14, and the observatory cleared for observing later that afternoon. A little under one and a half night of Espadons data were obtained, and a little more than half a night was dedicated to TCS engineering.
15AQ04 MegaCam Mar 16 - 23 8 Done Due to the severe winter weather, the exchange to MegaCam was postponed until the summit became accessible again (Mar 16).
15AQ05 ESPaDOnS Mar 24 - Apr 09 17 Done An excellent run, with only a handful of hours lost to clouds. Around 155h of observations were obtained, which is a little over 9 hours per night.
15AQ06 MegaCam Apr 10 - 27 18 Done The main loss of time for this run was due to weather (mostly just clouds), with about 31 hours lost. From a technical point of view, the run was relatively smooth. Some more engineering time was spent to tweak the new version of the Telescope Control System.
15AQ07 WIRCam Apr 28 - May 11 14 Done About 33h were lost to weather, and only a few minutes were lost to technical issues. Half the nights were photometric (mostly in the middle of the run), and the other half was affected by various degrees of cloudiness. With 25 nights behind us and 13 left, 65% of the hours for A-ranked programs have been validated, and 32% of B-ranked hours were validated.
15AQ08 MegaCam May 12 - 26 15 Done The weather was variable and sometimes poor at the beginning of the run, and until the last 6 nights. There were no major technical issues and most of the time list was due to bad weather (thin or thick clouds, some bouts of high humidity). The Image Quality has been excellent, and routinely below 0.8" in r, down to 0.5" at times.
15AQ09 WIRCam May 27 - Jun 08 13 Done Very little time was lost to weather (5.5h) or technical issues (<1.5h) during this 13-night run. The completion rate of programs is very good for this semester, with 96% of the A-ranked hours validated, and 56% of the B-ranked hours validated.
15AQ10 MegaCam Jun 09 - 22 14 Done A very good run with about 20h lost to weather, and no time lost to technical issues. When the sky was clear, the seeing was below 1", down to 0.45" in the r filter a handful of nights!
15AQ11 ESPaDOnS Jun 23 - Jul 04 13 Done The weather has been excellent during this run, with clear skies most of the nights, and seeing down to 0.5-0.6" on quite a few nights. A block of about 4 hours was used to test the new Telescope Control System on the first night of the run. A couple of hours was lost to technical issues, mostly during the first few nights.
15AQ12 Sitelle Jul 06 - 08 3 Done A very successful run, debugging hardware and software issues, doing focus sequences and pointing model, and taking some data.
15AQ13 MegaCam Jul 09 - 20 12 Done The last MegaCam run of the semester went relatively well. There were no technical issues. Time was only lost to bad weather (it snowed). About 90% of A-ranked hours for PI programs have been validated, and 70% for B-ranked hours.
15AQ13 ESPaDOnS Jul 21 - 31 11 Started


The QSO mode is well-adapted for target-of-opportunity (TOO) programs. If you want to submit unpredictable or time-critical TOO observations (e.g.: Gamma Ray Bursts, supernova) to be carried out in a queue mode with MegaCam, WIRCam or ESPaDOnS at any time during the current semester, you must use NorthStar and create a new proposal (see button at the bottom of the page after you've logged in) using "Director Discretionary" as the chosen community.

The CFHT Executive Director reviews each Discretionary Time proposal. If telescope time is allocated, the QSO Team will either ask the PI to fill in the required PH2 information, or extract the necessary information from the proposal and prepare the observations.


You need to contact the QSO Team? Please send an email to qsoteam -=at=- cfht.hawaii.edu. During a QSO run, communication between the investigators and the QSO Team will be done exclusively through the QSO Coordinator, not the QSO observer. For the status of your program, please refer first to the Web night reports (below).

Informations for Semester Preparation [ Return to top ]


The main concept behind the QSO mode is to execute programs only during the sky conditions (seeing, background, clouds, etc.) requested by Principals Investigators (PIs) in order to meet the programs' science goals. This is achieved by grouping all programs in a database and by selecting appropriate observations 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).


The QSO mode is offered with CFHT's 3 main instruments, the visible imager MegaCam, the infrared imager WIRCam, and the spectropolarimeter ESPaDOnS. Each instrument has a web page which offers technical details and help about observations:

Instruments offered in QSO mode
Exposure time calculators
DIET for MegaCam DIET for WIRCam ETC for ESPaDOnS

Phase 1 tool

The first step for applying for time in a queue mode is to submit a proposal to the Time Allocation Committee. For the Canadian, French, Taiwanese, Brazilian, Chinese, and Korean communities, this must be done through a Phase 1 tool.

CFHT is using the Northstar Phase 1 tool, adapted for CFHT. Please read the PH1 tutorials (MegaCam, WIRCam, ESPaDOnS) and NorthStar HelpFiles carefully!

It is STRONGLY recommended to carefully read the relevant document before starting your Phase 1.

Those documents are updated with new information before each semester. Investigators should spend some time to familiarize themselves with the QSO concept, the characteristics of the instruments, and the general procedures.

Quick checklist for Phase 1:
  • You have checked the PDF file for the proposal.
  • You have used the appropriate EXPOSURE TIME CALCULATOR.
  • You have requested time in HOURS (e.g. 14.7h).
  • Your requested time includes the appropriate OVERHEADS: readout time, telescope slews if appropriate.
    For the correct values to use, please see the instruments' tutorials.
  • If your program is a Snapshot program, it requests bad sky conditions (bad Image Quality or high extinction), is simple, and is made of short observations.
  • You have included on-sky calibrations if needed and if not already taken care of by the QSO Team (e.g.: photometric standard stars for narrow-band filters; spectroscopic standard stars).
  • You have contacted the QSO Team for any question or concern.

PLEASE REMEMBER YOUR PASSWORD! CFHT cannot retrieve NorthStar passwords, so if you have forgotten your login information, use the "Forgotten password?" option on the login page or register again.

CFHT Phase 1 tool MegaCam tutorial WIRCam tutorial ESPaDOnS tutorial
NorthStar access MegaCam WIRCam ESPaDOnS

For more information concerning the QSO Project and for any help during the preparation of your queue proposal, contact the QSO Team (qsoteam -=at=- cfht.hawaii.edu).


PH2 is a sophisticated Web based tool designed specifically for the Phase 2 submission of observations with MegaCam, WIRCam, and ESPaDOnS, and available from the CFHT Web site.

Accepted proposals can be entered in PH2 usually in June for the "B" semesters, and in November for the "A" semesters. The deadlines might vary from instrument to instrument.

  1. The telescope schedule is prepared after PIs have all entered their PH2; if not knowing the telescope schedule in advance causes problems for your PH2, please email qsoteam -=at=- cfht.hawaii.edu for further instructions.
  2. NEW since 09A: we now offer non-sidereal tracking with all 3 instruments. Please consult the Tutorials below for a few helpful tips (about guiding, maximum length of exposures, disabled options, etc.).
  3. NEW for WIRCam: users of the Staring Mode need to upload a Finding Chart (so we can make sure the target lands on a clean spot of the array!). The simple requirements for those charts are explained at the top of the Finding Chart page in PH2.
  4. If you have any question or comment, please email the QSO Team (qsoteam -=at=- cfht.hawaii.edu). Do NOT email individual members of the team, because this can delay answers depending on each member's schedule.

PH2 Documentation and Tutorials

The documentation has been re-organized and simplified. Two short documents present How QSO works at CFHT and the General Principals of Phase 2 (PH2). Each document starts with an Abstract and a set of keywords, to help users find topics of interest. All users are encouraged to read those documents at least once, which should take about 15 minutes.

The tutorials for each instruments have been simplified and updated. A short section at the top summarizes the basics of PH2. A Table of Content and links throughout the tutorials ease navigation. The tutorials are available within PH2 through the "Tutorial" button, or directly from the following links:

CFHT Phase 2 tool MegaCam tutorial WIRCam tutorial ESPaDOnS tutorial
Open PH2 PH2 Tutorial for MegaCam PH2 Tutorial for WIRCam PH2 Tutorial for ESPaDOnS
Exposure time calculators
DIET for MegaCam DIET for WIRCam ETC for ESPaDOnS

When ready, you may login to PH2:

If you get an error message that says "... can't establish a connection to the server at qso.cfht.hawaii.edu:2001...", please check the firewall on your machine and/or provider. Port 2001 is a non-traditional http port that might be blocked in the path to your internet.

MegaCam/WIRCam/ESPaDOnS If you are not already familiar with the MegaCam and WIRCam mosaic cameras or the spectropolarimeter ESPaDOnS, or for any news concerning these instruments, you should consult their respective Web pages:

Instruments offered in QSO mode

Informations useful during Observations [ Return to top ]


Each day during a QSO run, a CFHT astronomer prepares various queues suitable for the coming night, based on PI requests for Image Quality and sky conditions, and ranking of the programs. "A" programs are given priority, followed by "B", "C", and Snapshot programs. Queues are also made as much as possible to give each agency its share of the night; if an agency has 30% of the allocated time on a given instrument, it will be found on average in about 30% of each queue. At night, depending on the sky conditions, the CFHT Remote Observer selects and executes one or more queues. Each exposure receives a grade indicating the quality of the data (grades 1 and 2 are good for the science proposed), and most exposures also receive comments about sky conditions, technical issues, etc. The next morning, a CFHT astronomer reviews those grades and comments, and validates exposures which are good enough for the science goals proposed; only validated exposures are taken out of a PI's allocated time. Exposures which are not validated will be tried again if possible.

Night Reports

During a semester, night reports are available after the QSO Team has performed the data evaluation for the previous night. The night reports also allow the user to extract the current status of any QSO program. Therefore, it is not necessary to contact the QSO Team to know what's happening with an observing program. More information, notably regarding the weather conditions and data distribution, have also been added to these reports. Statistics on the QSO mode are also published during the current semester (see next section).


The current statistics on the QSO mode are available. This includes the time distribution for the different Agencies as well as some global numbers on the programs.


The QSO mode is well-adapted for target-of-opportunity (TOO) programs. If you want to submit unpredictable or time-critical TOO observations (e.g.: Gamma Ray Bursts, supernova) to be carried out in a queue mode with MegaCam, WIRCam or ESPaDOnS at any time during the current semester, you must use NorthStar and create a new proposal (see button at the bottom of the page after you've logged in) using "Director Discretionary" as the chosen community.

The CFHT Executive Director reviews each Discretionary Time proposal. If telescope time is allocated, the QSO Team will either ask the PI to fill in the required PH2 information, or extract the necessary information from the proposal and prepare the observations.

Information useful after Observations [ Return to top ]


Data are detrended after each run (MegaPrime and WIRCam) or reduced after each night (ESPaDOnS) by a team of astronomers and software engineers. PIs who request immediate (or quick) access to their data can receive raw data or detrended data as soon as available. When data are ready, PIs receive an email from CFHT with the location of their data; the data (detrended, and raw for some instruments), documentation, instructions, and metadata are downloadable from a private URL with a unique key sent to PIs.

Each instrument has its own data reduction pipeline, maintained by CFHT astronomers and software engineers:


The DADS Team distributed data to PIs. At the beginning of each semester or when data are available, PIs receive information on how to retrieve their data.

CFHT offers a tool called cfhtget, which can be used to efficiently retrieve ESPaDOnS data: MacOSX and Linux versions are available.

Proprietary period

The proprietary period of QSO data extends by default to 1 year + 1 month starting at the end of the QSO semester. For instance, data taken for the 2009B semester (August 1 - January 31) will have a default release date set to 02/28/2011. The extra month is allowed because of possible delays in the data reduction distribution of observations carried out near the end of a semester. If an extension is requested during the Phase 1 period and is approved by TAC, a new date will be set for this program through the QSO system. This release date for the QSO data is indicated in the fits headers by the keyword REL_DATE.

Note: Since data can be taken at almost any time during a semester in a queue mode, it will not be possible to change the release date after the beginning of a semester.

For snapshot programs, the proprietary period is three months following the end of the semester. The CFHTLS data have a different release date, regarding the proprietary period system supported by the Board of Directors.

Archived information