Time Allocation and Accounting

The expected time allocations to each partner for the current and next semesters are listed in the relevant Call for Proposals.

Nominal Steady-state Time Allocation

A schematic of the steady-state time allocation is given at right (not drawn to scale).

After allowance of 10% of the semester for Observatory engineering and Director's Discretionary time, 10% of the remainder is allocated to the host (University of Hawaii or CONICYT/Chile). The allocation to staff is at the discretion of the Gemini Director and depends in part on the assessment of proposals by the staff TAC; this time is contributed proportionately by each partner country. The combined total of engineering, discretionary and staff time will normally not exceed 25%. The remainder of the available time, i.e. total time less actual engineering (which may be greater than 10%) plus host and staff times, is distributed amongst the partner countries according to their financial involvement in the Gemini Observatory.

The two examples that follow assume 10% and 14% actual engineering time, respectively, and 10% staff time. For computational convenience it is assumed that there are 10 hours available per night on average.

Partner	Allocated classical nights (or queue hours) per telescope (for 10% engineering time)	Allocated classical nights (or queue hours) per telescope (for 14% engineering time)
US	123 nights (1230 hours)	117 nights (1168 hours)
Host (UH or Chile)	33 nights (329 hours)	33 nights (329 hours)
UK	65 nights (650 hours)	62 nights (618 hours)
Canada	39 nights (390 hours)	37 nights (371 hours)
Australia	13 nights (130 hours)	12 nights (124 hours)
Chile	13 nights (130 hours)	12 nights (124 hours)
Argentina	7 nights (65 hours)	6 nights (62 hours)
Brazil	7 nights (65 hours)	6 nights (62 hours)
Gemini Staff	30 nights (296 hours)	28 nights (281 hours)
Engineering/DD	37 nights (365 hours)	51 nights (513 hours)

The figures given in Gemini Newsletter #20 were incorrect as they did not include the maximum allowance of 10% engineering time before host time is taken 'off-the-top'.

Time charging and balance

Classically-scheduled programs are counted as nights scheduled multiplied by a weather correction factor (currently 0.75). Queue-scheduled programs are counted as hours used including all overheads (acquisition, detector readout, data quality assessment etc.) and night-time calibration. Any calibrations taken during day-time (e.g. using the facility calibration unit) are not charged.

In the case of the queue-scheduled programs, it will be impossible to predict in detail ahead of time how many hours will go to each partner, because selection of the program to be executed will depend on the changing conditions. It is not necessary that the agreed fractional allocations be satisfied every semester, only that they approach these values over the longer term (i.e. 2-3 semesters). However, there is a given amount of observing time and if one partner exceeds its allotment another one will fall behind its allotment. Therefore, the queue will be adjusted to ensure that no partner seriously deviates from its allotment. This adjustment can be made during initial queue merging (by modifying the merging quanta) and periodically throughout the semester by adjustment of the execution weights.

Last update August 31, 2006; Rachel Mason and Bob Blum