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
2015B 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 2016A is now closed for most PIs. PH1 for 2016B will open around Feb 21.

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

2016A programs

List of 2016A QSO programs for MegaPrime, WIRCam, ESPaDOnS, and SITELLE.

QrunID Instrument HST Dates # Nights Status Run Summary
16AQ01 MegaCam Feb 1 - 15 15 Started  
16AQ02 ESPaDOnS Feb 16 - Mar 2 16 Not Started  
16AQ03 Sitelle Mar 3 - 7 5 Not Started  
16AQ04 MegaCam Mar 8 - 16 9 Not Started  
16AQ05 WIRCam Mar 17 - 21 5 Not Started  
16AQ06 ESPaDOnS Mar 22 - 28 7 Not Started  
16AQ07 MegaCam Mar 29 - Apr 13 16 Not Started  
16AQ08 WIRCam Apr 14 - 26 13 Not Started  
16AQ09 MegaCam Apr 27 - May 12 16 Not Started  
16AQ10 ESPaDOnS May 13 - 26 14 Not Started  
16AQ11 MegaCam Mar 27 - Jun 7 12 Not Started  
16AQ12 ESPaDOnS Jun 8 - 23 16 Not Started  
16AQ13 MegaCam Jun 24 - Jul 7 14 Not Started  
16AQ14 Sitelle Jul 8 - 11 4 Not Started  
16AQ15 WIRCam Jul 12 - 24 13 Not Started  
16AQ16 MegaCam Jul 25 - 31 7 Not Started  

2015B schedule and programs

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

QrunID Instrument HST Dates # Nights Status Run Summary
15BQ01 ESPaDOnS Aug 1 - 4 4 Done Despite the threat of storm Guillermo and about one night and a half lost to fog and high humidity, these first four nights of the semester were relatively productive. There were no technical issues.
15BQ02 Sitelle Aug 4 - 9 6 Done This second Sitelle run, dedicated to engineering tests, characterization, and scientific observations was very successful.
15BQ03 MegaCam Aug 10 - 19 10 Done This was a poor MegaCam run, with high humidity, fog, and overcast skies. Only 18h of scientific observations were obtained.
15BQ04 WIRCam Aug 20 - 25 6 Done This short run was severely affected by bad weather, with almost 50h lost to high humidity and fog. Only 8h of observations were validated.
15BQ05 ESPaDOnS Aug 26 - Sep 3 9 Done Despite the threat of hurricanes Kilo and Ignacio, this run was overall successful. Some time was lost to high humidity, but less than expected.
15BQ06 MegaCam Sep 4 - 17 14 Done The two main sources of lost time this run were high humidity (32h) and the time needed to recover from 2 power outages at the summit (12h). The Image Quality was generally excellent, with measurements frequently below 0.5" (in r).
15BQ07 ESPaDOnS Sep 18 - Oct 1 14 Done Almost 55 hours were lost to weather, but there were no technical difficulties otherwise. Good progress was made on a lot of programs.
15BQ08 MegaCam Oct 2 - 19 18 Done This long MegaCam run was relatively productive, despite almost 60 hours lost to weather. Seven or 8 nights had photometric skies, with thick clouds, high humidity, or fog affecting the rest of the time.
15BQ09 WIRCam Oct 20 - 26 7 Done The majority of the nights were photometric during this short WIRCam run, which helped catch up since the first run of the semester had been severely affected by bad weather. We are halfway through the allocation of WIRCam nights, and about a third of all observations have been obtained.
15BQ10 MegaCam Oct 27 1 Done This is a bright-time engineering night to test a new filter exchange mechanism for MegaCam.
15BQ11 ESPaDOnS Oct 28 - Nov 3 7 Done The run was lengthened by 1 night to allow the technical staff some more time with the MegaCam filter exchange mechanism. With the exception of about 1h lost to fog and a couple of hours lost to technical issues, observations were taken every night from twilight to twilight. The Image Quality was well below 1 arcsec except on the last night; one night even had seeing between 0.3 and 0.5 arcsec!
15BQ12 MegaCam Nov 4 - 16 13 Done The weather was generally poor during this run, except at the beginning and at the very end of the run. Fewer than about 3h were lost to technical issues, the majority due to a power outage in Waimea; 60h were lost to weather (precipitation, clouds).
15BQ13 ESPaDOnS Nov 17 - Dec 2 16 Done The exchange to MegaCam initially scheduled for Dec 3 indeed happened that day. The ESPaDOnS run was not extended.
For this ESPaDOnS run, two full nights were lost to weather, and a few more hours to high humidity. The time lost to technical issues was minimal.
15BQ14 MegaCam Dec 3 - 16 13 Done The exchange to MegaCam initially scheduled for Dec 3 indeed happened that day, despite a major issue with MegaCam's electronics. For the first 4 nights, half of the mosaic has unresponsive or misbehaving chips, and exhibits a higher level of noise that is also changing with time. The issue was addressed and fixed Monday Dec 7.
15BQ15 WIRCam Dec 17 - 27 11 Done A poor WIRCam run with 60 hours lost to weather.
15BQ16 Sitelle Dec 28 & 29 2 Done Sitelle engineering for the pointing model, focus model, and other basic tests.
15BQ17 MegaCam Dec 30 - Jan 07 9 Done The run was cut short to insert the Sitelle Science Verification run.
15BQ18 Sitelle Jan 8 - 12 5 Done The Sitelle Science Verification run was very successful. Thanks to the excellent weather, and to the dedication of the technical staff and the Sitelle science team, almost all the time was dedicated to science. About 5 hours were dedicated to some engineering tests right at the beginning of the first night, and only 4 hours were lost to high winds. The Science team is reducing data and checking the performance of CFHT's newest instrument.
15BQ19 ESPaDOnS Jan 13 - 28 16 Done An excellent long run with only 5 hours lost to weather (high winds), about 4 hours of engineering time to test the Olapa 2amp mode, and 5 mornings of daytime Venus observations. The outstanding conditions allowed us to get a head start on 2016A program and obtain on average 10h05 of validated observations per night.
15BQ20 MegaCam Jan 29 - 31 3 Done This run is used for a mix of 15B and 16A programs. MegaCam observations continue into February.

2015A information

The run summaries and list of accepted programs have been archived.


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
MegaCam WIRCam ESPaDOnS Sitelle
Exposure time calculators
DIET for MegaCam DIET for WIRCam ETC for ESPaDOnS ETC for Sitelle

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, Sitelle) 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 Sitelle tutorial
NorthStar access MegaCam WIRCam ESPaDOnS Sitelle

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 SITELLE tutorial
Open PH2 PH2 Tutorial for MegaCam PH2 Tutorial for WIRCam PH2 Tutorial for ESPaDOnS PH2 Tutorial for SITELLE
Exposure time calculators

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