Down Time

The down time statistics are based on individual fault reports. In Table 1 I give the general down time statistics for period 34.

A total of 117 fault reports were submitted, with an average time lost of 7 min per fault, for a total down time of 0.7% (0.8% on scheduled observing nights). Of these, 82 reported no time lost, 35 reported $<$ 2 hrs lost, and none reported 2 or more hrs lost.

Table 1: Technical down time statistic period 34: 2006-10-01 to 2007-04-01
Night included Time lost Nights Percentage$^a$ Last period
All nights 850 min 182 0.7% 0.9%
Scheduled observing nights$^b$ 800 min 142.5 0.8% 1.2%
Technical nights 50 min 29.5 0.3% 0.4%
Service nights$^c$ 50 min 11.5 0.6% 0.3%
Visitor instruments 0 min 10 0.0% 0.2%
$^a$ 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

This compares to a down time of 0.9% over all nights (1.2% on scheduled observing nights) in period 33. For that period 95 faults reports were submitted with an average time lost of 10 min per fault. Of these, 66 reported no time lost, 23 reported $<$ 2 hr lost, and 2 reported 2 or more hrs lost.

The most important thing to note is the continuing low down time, with the down time basically the same as in the last two periods. Compared to period 33 there were less problems causing a large ($\ge$2 hr) amount of down time, but there were slightly more faults causing small amount ($<$2 hr) down time.

Thomas Augusteijn 2008-01-11