1 - WHT OPERATIONS DURING 2011A ------------------------------- 1.7% of the observing time was lost to technical problems. This is well below the target level of 5%. The numbers of nights allocated to each common-user instrument in 2011A were approximately: ISIS 58; LIRIS 31; AF2 13; prime-focus imaging 0; ACAM 19; OASIS 1; INGRID 6. (Where an observer requested two instruments, e.g. LIRIS + ACAM, the credit has been split between the two.) ISIS and LIRIS remain our most popular instruments, with a 58% share of all nights, and 70% of nights allocated to common-user instruments. These fractions are similar to the average during the last 3 years. The WHT hosted 4 visiting instruments this semester: GHAFAS, PNS and SAURON. GLAS was not offered in 2011A following its failure in 2009A to deliver sufficient power. 39 user feedbacks were received for runs during 2010B. All rated the run 'good' or 'excellent', with many positive comments about the support. Comments on the Residencia: five feedbacks included favourable comments on the newly-refurbished rooms; three commented negatively about the quality of the food; two commented on problems with noise. 2 - TIME-LOSS STATISTICS FOR 2011A ---------------------------------- 47 technical faults, 31 hours lost, mean 0.7 hours per fault. The faults arise in a broad range of sub-systems. Two faults caused more than 3 hours to be lost: 6 h lost in Mune to a CCD shutter failure. 4 h lost in July due to data disk filling up. NB these statistics (as in previous reports) refer to *all* nights, including S/D/commissioning, and nights when visitor instruments were used. 3 - ACTUAL USE OF S/D/STANDDOWN IN 2011A ---------------------------------------- Service Observed 14.8 Bad weather 4.7 Technical problems 1.2 D/comm Tel. quality control 0.5 Instr. quality control 2.6 Commissioning 1.1 Aluminising 0.0 Bad weather 1.3 Technical problems 0.4 ---- 26.6 Total S = 20.7 = 14.8 + 5.9 associated bad weather + technical problems. Total D = 5.9 = 4.2 + 1.7 associated bad weather + technical problems. 4 - WEATHER AND TECHNICAL DOWNTIME IN 2011A ------------------------------------------- The last three columns below give for each month the numbers of observing hours lost to bad weather and to technical problems, and the number of nights considered when compiling these statisics (= all those which were not S/D/commissioning or own-instrument). Mon Yr weath tech nights hrs hrs 2 11 60 1 22 3 11 60 0 17 4 11 64 0 19 5 11 29 4 23 6 11 10 9 21 7 11 9 3 20 Chris Benn 3 October 2011, 15 May 2012