Down Time

The down time statistics are based on individual fault reports. In Table 1 I give the general down time statistics for period 39. A total of 93 fault reports were submitted, with an average time lost of 8 min per fault, for a total down time of 0.7% (0.9% on scheduled observing nights). Of these, 63 reported no time lost, 30 reported $<$ 2 hrs lost, and none reported 2 or more hrs lost.

This compares to a down time of 0.2% over all nights (0.2% on scheduled observing nights) in period 38, and 1.8% over all nights (0.1% on scheduled observing nights) in period 37. Of the 88 fault reports reported in period 38, 66 reported no time lost, 22 reported $<$ 2 hrs lost, and none reported 2 or more hrs lost. Of the 95 fault report in period 37, 63 reported no time lost, 38 reported $<$ 2 hrs lost, and 4 reported 2 or more hrs lost.

Table 1: Technical down time statistic period 39: 2009-04-01 to 2009-10-01

Night included	Time lost	Nights	Percentage$^a$	Last semester	Last summer
All nights	730 min	183	0.7%	0.2%	1.8%
Scheduled observing nights$^b$	545 min	116	0.9%	0.2%	0.1%
Technical nights	165 min	28.5	1.1%	0.2%	0.1%
Service nights$^c$	180 min	38.5	0.9%	0.2%	0.1%
Visitor instruments	20 min	19	0.2%	0.0%	6.8%
$^a$ Taking the average length of time within nautical twilight. Exact numbers for each night
are used when looking at ``All nights''
$^b$ Excluding technical nights and visitor instruments
$^c$ Excluding service nights with SOFIN

Although higher then the all time low in downtime last semester, the reported downtime remained low with no major problems occurring during period 39. The downtime over the one year covered by period 38 and 39 is 0.4%.