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Telescope Time Charging

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Top level principles for how telescope time is charged

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.