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Historical statistics

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The reports in this Section originate from specific requests from committees or from internal analysis of operations questions. This information will only be updated as time allows or as the need for updated analysis arises.

The Effect of Program Length

An investigation was carried out to better understand how the requested program length affects the probability of a program getting the requested data. Only semesters 2005A-2009B were included in this investigation since these semesters closely reflect the current queue planning principles and methods, while this is not the case for the earlier semesters.


Comparison of the distribution of program lengths for scheduled programs (gray) and programs that got at least 75% of the requested data (orange). For band 1 and 2 the distributions are identical. Thus, the program length for these two ranking bands has no influence on whether the program gets data. For band 3 there is a tendency that more of the shorter programs get executed. This is as expected since the queue planning focuses on selecting programs from band 3 that have a fair chance of getting a significant faction of the requested data. The median program length in band 3 for scheduled programs is 9 hours, while the median program length for those that got at least 75% of the requested data is 6 hours.

Non-Sidereal Observations

The Figure shows the fraction of time allocated to non-sidereal programs, from 2010A to 2011B. On average, Gemini North has about 9% of its time allocated to non-sidereal programs, with an even higher fraction in 2011B. Gemini South currently features less non-sidereal programs. The reason for this discrepancy is currently not well understood, although it should be noted that Gemini North's host, the University of Hawaii, is involved in many non-sidereal programs.


The fraction of time allocated to non-sidereal programs.

User Demand for Target-of-Opportunity Programs

The Figure shows the percentage charged for Gemini's Target of Opportunity (ToO) programs, sorted by band. It is readily apparent that we are using 20-25% of band 1 time on ToOs. ToOs come in two varieties:

  • Rapid ToOs: response times vary from a few minutes up to 24 hours. In 2010A, there were 10 triggers per month per site.
  • Standard ToOs: response times greater than 24 hours. in 2010A, there were 20 triggers per month per site.


Fraction of time charged for Target of Opportunity programs, by band.

New Users

The Table presents the number of new Gemini users, where a "new" user is defined as a PI name with no programs on Gemini in any prior semester (starting with 2000). The numbers are relatively stable, with on average 50 new PIs each semester, representing 21.9% of all Gemini PIs. 


The number of new Gemini PIs over the past few semesters.

Historical statistics | Gemini Observatory


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