GeminiFocus April 2016 | Page 18

Figure 2. In 10% bins, the fraction of programs ending the semester at a given completeness level. Top: an unusually good semester (Gemini South 2012A). Bottom: an unusually bad semester (Gemini North 2014A). 16 The two charts in Figure 2 show histograms of queue program completion at Gemini South 2012A and Gemini North 2014A. The very sparse tail of programs below the 100%-complete bin in the “exceptional” semester compares with large numbers of programs ending at 90% and below in the “bad” semester. Numerous programs were not started at all in 2014A at Gemini North. Note that the queue preferentially protects Band 1 observations in a “bad” semester, as it should. In the “exceptional” semester at Gemini South the Band 1 completion exceeded that of Band 2, which in turn exceed- GeminiFocus ed that of Band 3. In a “normal” semester (neither exceptional nor terrible) results lie somewhere between these extremes, with Band 1 completion higher than that in the other two bands. While Band 2 completion usually exceeds that in Band 3 during a “normal” semester, it is a signature of bad weather that in some semesters Band 3, in which programs can typically take poorer conditions, does better. As you can see in Figure 1, in recent semesters, Band 3 has done well rel ]]