GeminiFocus 2019 Year in Review | Page 69

Semester 2018B Outcomes We’re now in the thick of Semester 2019A and taking stock of the outcome of 18B. Pre- liminary completion results for programs in the regular queue (in other words, ex- cluding Targets of Opportunity and block- scheduled instrument modes) are shown in Figure 8. Band 1 programs at both sites fared rather well, three quarters of them reaching 100% completion. In the North, Band 3, which typically takes the more re- laxed observing conditions, fared relatively worse — another reflection of the fact that 18B was better than either of the preceding B semesters in Hawai‘i. In the South, the completion rate was better than it has been for many semesters, thanks to a healthy percentage of stable, good conditions despite the loss of five nights to a major earthquake in January 2019. Note that in 18B we took data on the last of the traditional “rollover” programs; from now on, regular queue Band 1 programs (except Target of Opportunities, Fast Turnaround, Director’s Discretionary, and Large and Long Programs) have one semester of “persis- tence,” and so some of those will continue to accumulate data as we continue into 2019A. Gemini North Survives Wild Weather As we reported in our recent e-newscast, on February 10, 2019, a low-pressure system (Figure 9, next page) subjected Maunakea to some of the highest wind speeds ever recorded. While there’s reason to be skepti- Figure 8. For Gemini South (upper) and Gemini North (lower) the completion histogram for Semester 2018B. Horizontal axis shows the program completion in 10% bins, and vertically the colored bars show the fraction of programs in Bands 1, 2, and 3, which reached that completion percentage. Main features are described in the text. Credit: Andy Adamson January 2020 / 2019 Year in Review GeminiFocus 67