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Policies Regarding Observing

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Telescope Time Charging

The Gemini Telescopes are operated both in queue and in classical mode. The time charged depends on the mode of operation. The top-level principles for determining the time charged are as follows.

  • Queue time is charged from start of slew to the target and until the start of the slew to the next target, or alternatively to the end of the observation sequence if this ends because of twilight, weather or other causes.
  • Queue time is not charged for observations that fail to meet the PI requirements. Quality assessment is done on all data taken in queue in band 1-3. Data set to "pass" result in program or partner charge, time spent on data set to "usable" or "fail" are not charged. Program time is charged for science and "program calibrations", and their acquisition observations. Partner calibrations and their acquisitions are charged to the partner(s) of the program, but not to the program time.
  • Queue time is charged only for executed observations. Planned, but unexecuted, observations have no influence on the total time charged.
  • For band 4 (poor weather programs) queue time is charged to the program, but not counted in the determination of the partner imbalances, i.e. the time is “free” to the partner.
  • Classical time is charged for the full night between nautical twilight and nautical twilight, independent of weather losses or losses due to equipment problems. The time is charged at a 75% rate. E.g., for a 10 hour night, the time charged is 7.5 hours, independent of the weather losses or losses due to equipment problems. Starting with semester 2007B, parts of classical nights may be used for queue observations if the conditions do not allow the classical program or its backup program to be executed. In this case, the charge towards the classical program is determined as the time between nautical twilight and nautical twilight, less any time charged to queue programs. The time is charged at the 75% rate.
  • At the end of each semester the partner imbalances are calculated using the partner shares (with deductions for any time off the top for engineering, commissioning, campaigns, system verification etc.). Gemini keeps track of the accrued partner imbalance and makes the information available to the Operations Working Group each semester at its semi-annual meeting. The Operations Working Group takes the imbalances into account when agreeing on the distribution of the telescope time available in the following semester.
  • See also the queue planning and execution description.

    Data Rights and Proprietary Periods

    All data taken with the Gemini telescopes is the property of Gemini Observatory. PIs of Gemini programs are allowed exclusive access to the pixel data for their programs for a default proprietary period as listed in the table below.  After the proprietary period the data are publicly available. All baseline calibration data (usually arcs, flats, and standard stars) are publicly available immediately. The proprietary period for system verification and demo science data is usually a few months but can vary, see the specific call for proposals for details.

    Metadata for programs, including the title, investigators, abstract, and FITS headers, is public. In special cases, such as for multi-year campaigns, the FITS headers may be made private until the end of the proprietary period.

    Changes to the proprietary period can be requested in the Experimental Design section of the proposal or by contacting the appropriate Head of Science Operations for existing programs.

    Program/Data Type Proprietary Period
    Baseline calibration None
    System Verification/Demo Science 2-3 months (see call)
    Fast Turnaround, Director's Time 6 months
    All other (e.g. Queue/Classical/LLP/Poor Weather) 12 months
    Competitive Target of Opportunity (Queue program) 12 months, data may be shared - See the Policy Page
    Competitive Target of Opportunity (DD program) May vary - See the Policy Page

    Data Distribution

    All Gemini raw data some processed data are distributed via the Gemini Observatory Archive. Raw data files from facility instruments usually appear in the archive within a few minutes of being taken. During the proprietary period PIs may access their data using the Gemini program key provided in the time acceptance email. A calibration association service is provided for identifying the appropriate calibration files. The archive also provides program abstracts, observing logs, and links to publications based on the data.

    More information on data assessment, the archive, and data reduction software can be found on the Data and Results page.

    Policies for Competitive ToOs

    Effective November 20, 2017, the policies described below will regulate the activation of Target of Opportunity (ToO) programs, the priorities for their execution as well as the data access rights for the acquired data. The policies apply when multiple teams activate ToOs on the same target and on the same or subsequent nights.

    Approval of ToO Triggers and DD Time

    1. To be activated, Queue ToOs must be scientifically aligned with the nature of the event for which the trigger is requested.  This is a general rule that applies to all ToO programs.
    2. DD proposals will not be accepted if they effectively duplicate, in their observational setup, an existing Queue ToO that has been activated to observe the same target. DD proposals that are accepted prior to the activation of an existing Queue ToO will be subject to the Prioritization and Data Sharing Policies discussed in II. and III. below.

    Prioritization for ToO Triggers and DD Time

    1. In case of multiple Queue ToO triggers on the same target and night, the Gemini Observatory will attempt to work with the PIs to prioritize the observations so that the science is maximized. If no consensus can be reached among the PIs, or if no coordination is possible, the Gemini Observatory reserves the right to prioritize the observations according to the following criteria: 1) how well the scientific justification of the proposal aligns with the nature of the target;  2) the ITAC ranking of the proposals, if available; 3) the temporal order in which the triggers are activated; 4) additional considerations to maximize science, such as whether the Gemini observations are coordinated with data from other observatories (e.g. Chandra, HST, other ground facilities).
    2. As a rule, all DD programs will be given lower priority than Queue ToO programs. However, DD programs that are awarded to extend a Queue ToO program that has used all of its allocation during the course of an observing campaign will have higher priority than other DD programs. 

    Policies on Data Access Rights for ToO and DD Programs 

    The following policies only apply when multiple ToOs (rapid or standard) are triggered on the same target and, for objects that vary significantly on timescales shorter than 24 hours, on the same night. A distinction is made between ToOs approved as part of the regular Queue, and ToO approved using DD time.

    1. Data taken as part of Queue ToOs have a standard 12-month proprietary period. However, for exceptional events, when multiple ToOs (rapid or standard) are triggered on the same target, Queue ToO data taken for a given PI will be shared with PIs of other programs who also trigger on the same target and ask for the same instrumental configuration (i.e., the same instrument and observing mode). For targets whose properties are known or expected to change appreciably within the course of one night, the data sharing policy is reset each night. For all other targets, in exceptional circumstances, data sharing might be extended to include requests submitted in subsequent nights, at the discretion of the Observatory. For the purpose of time accounting, the total time spent observing the source will be divided equally amongst all teams receiving the data. 
    2. All data acquired as part of an approved Gemini DD program hold a standard proprietary period of 6 months. However, the Observatory reserves the right to remove the proprietary period in exceptional circumstances. This right can be exercised before, during or after the execution of the program. Circumstances that might require to reduce or remove the proprietary period of DD data include, but are not limited to, follow-up of rare astronomical phenomena. The PI will be notified of any changes to the proprietary period of DD data.

    For DD requests to follow up on an embargoed target, DD data will be made public, at the discretion of the Observatory, only after the target is released to the community at large. Before that, however, DD data will be made accessible to all teams using Gemini to follow-up on the same object.