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Over-Subscription Rates

Over-Subscription of Gemini Telescope Time

The figure below show the average (weighted by partner share) over-subscription of the Gemini telescopes between semesters 2005B and 2014A. The over-subscription shown on the left axis is calculated as the ratio of the total Gemini time requested to the total advertised available science time. Requests for Exchange time are not included. The available Gemini science time includes all three science bands 1, 2 and 3, and the requested time does not include program calibrations. Starting in 2013A, the UK is no longer a Gemini partner, increasing the amount of time available to the other partners by about 20%.

Typically the Observatory executes about 65% of the advertised science time in the Call for Proposals, the remaining time going primarily to weather loss. Currently, the available time advertised in the Call for Proposals is filled to the 80% level with classical and queue bands 1, 2 and 3 programs, to avoid overfilling the queue and disappointing band 3 investigators. Poor weather programs are designed to use any remaining very poor but useable telescope time.

Telescope time used in program calibration varies by instrument. For GMOS, calibrations add about 5% to the program time, for NIRI 10%. for GNIRS and NIFS 23%. The standard, baseline, calibrations are described on the GMOS Baseline Calibrations webpage, the NIR Baseline Calibrations webpage, and the Mid-IR Baseline Calibrations webpage. The Observing Overheads page summarises all overheads associated with Gemini observations.

Allowing for the 80% queue filling factor and adding a 9% overhead for calibrations at Gemini North, and 5% for Gemini South, for the typical instrument distributions, the effective over-subscription rate is 1.4 times the values shown in the plots below for Gemini North, and 1.3 times the value for Gemini South. The values along the right axis show the effective over-subscription rate allowing for calibration overheads and the 80% queue filling factor; currently Gemini North is over-subscribed by about a factor of three and Gemini South about a factor of two.

The Demand for Gemini Telescope Time page shows the demand in number of hours, without the division by available time. The over-subscription for each partner, calculated as described above, is also available. Note that the y-axis scales differ - the upper limit is 5 for partners Australia, UK and US, and 3.5 for partners Argentina, Brazil and Canada, and for the host institutions and Gemini staff.

 

 

[Average oversubscription]
Figure 1: Average over-subscription of Gemini North and South telescope time between semesters 2005B and 2014A, calculated as described above. The drop in subscription rates for the South in 07B can be attributed to the loss of GNIRS. The effective over-subscription rate is 1.4∗ the values shown for Gemini North, and 1.3∗ the values shown for Gemini South, as the queue is filled to 80% to reflect typical semester loss rates and calibration overheads are not included. Values along the right axis show the effective oversubscription rate, 1.35∗ the values on the left axis.


 

Argentina

[AR oversubscription]
Figure 2: Over-subscription of Gemini North and South telescope time between semesters 2005B and 2014B, for partner Argentina. The over-subscription is the ratio of the total requested time to the total available science time in classical and bands 1, 2 and 3 for the partner, as advertised in each semester's Call for Proposals. The effective over-subscription rate is 1.4∗ the values shown for Gemini North, and 1.3∗ the values shown for Gemini South, as the queue is filled to 80% to reflect typical semester loss rates and calibration overheads are not included.


 

Australia

[AU oversubscription]
Figure 3: Over-subscription of Gemini North and South telescope time between semesters 2005B and 2014A, for partner Australia. The over-subscription is the ratio of the total requested time to the total available science time in classical and bands 1, 2 and 3 for the partner, as advertised in each semester's Call for Proposals. The effective over-subscription rate is 1.4∗ the values shown for Gemini North, and 1.3∗ the values shown for Gemini South, as the queue is filled to 80% to reflect typical semester loss rates and calibration overheads are not included.


 

Brazil

[BR oversubscription]
Figure 4: Over-subscription of Gemini North and South telescope time between semesters 2005B and 2014A, for partner Brazil. The over-subscription is the ratio of the total requested time to the total available science time in classical and bands 1, 2 and 3 for the partner, as advertised in each semester's Call for Proposals. The effective over-subscription rate is 1.4∗ the values shown for Gemini North, and 1.3∗ the values shown for Gemini South, as the queue is filled to 80% to reflect typical semester loss rates and calibration overheads are not included.


 

Canada

[CA oversubscription]
Figure 5: Over-subscription of Gemini North and South telescope time between semesters 2005B and 2014A, for partner Canada. The over-subscription is the ratio of the total requested time to the total available science time in classical and bands 1, 2 and 3 for the partner, as advertised in each semester's Call for Proposals. The effective over-subscription rate is 1.4∗ the values shown for Gemini North, and 1.3∗ the values shown for Gemini South, as the queue is filled to 80% to reflect typical semester loss rates and calibration overheads are not included.


 

Gemini Staff

[Staff oversubscription]
Figure 6: Over-subscription of Gemini North and South telescope time between semesters 2005B and 2014A, for Gemini Staff. The over-subscription is the ratio of the total requested time to the total available science time in classical and bands 1, 2 and 3 for the staff, as advertised in each semester's Call for Proposals. The effective over-subscription rate is 1.4∗ the values shown for Gemini North, and 1.3∗ the values shown for Gemini South, as the queue is filled to 80% to reflect typical semester loss rates and calibration overheads are not included.


 

Hosts: Chile and the University of Hawaii

[Host oversubscription]
Figure 7: Over-subscription of Gemini North and South telescope time between semesters 2005B and 2014A, for the Gemini South host Chile and the Gemini North host University of Hawaii. The over-subscription is the ratio of the total requested time to the total available science time in classical and bands 1, 2 and 3 for the host, as advertised in each semester's Call for Proposals. The effective over-subscription rate is 1.4∗ the values shown for Gemini North, and 1.3∗ the values shown for Gemini South, as the queue is filled to 80% to reflect typical semester loss rates and calibration overheads are not included.


 

UK

[UK oversubscription]
Figure 8: Over-subscription of Gemini North and South telescope time between semesters 2005B and 2012B, for partner UK. The UK is no longer a partner in 2013A. The over-subscription is the ratio of the total requested time to the total available science time in classical and bands 1, 2 and 3 for the partner, as advertised in each semester's Call for Proposals.The effective over-subscription rate is 1.4∗ the values shown for Gemini North, and 1.3∗ the values shown for Gemini South, as the queue is filled to 80% to reflect typical semester loss rates and calibration overheads are not included.


 

US

[US oversubscription]
Figure 9: Over-subscription of Gemini North and South telescope time between semesters 2005B and 2014A, for partner US. The over-subscription is the ratio of the total requested time to the total available science time in classical and bands 1, 2 and 3 for the partner, as advertised in each semester's Call for Proposals. The effective over-subscription rate is 1.4∗ the values shown for Gemini North, and 1.3∗ the values shown for Gemini South, as the queue is filled to 80% to reflect typical semester loss rates and calibration overheads are not included.