Down Time

The down time statistics are based on individual fault reports. In Table 1 I give the general down time statistics for period 33.

A total of 95 fault reports were submitted, with an average time lost of 10 min per fault, for a total down time of 1.1% (1.3% on scheduled observing nights). Of these, 66 reported no time lost, 23 reported $<$ 2 hrs lost, and 2 reported 2 or more hrs lost.

Table 1: Technical down time statistic period 33: 2006-04-01 to 2006-10-01

Night included	Time lost	Nights	Percentage$^a$	Last period
All nights	935 min	183	1.1%	0.7%
Scheduled observing nights$^b$	860 min	137	1.3%	0.6%
Technical nights	55 min	23	0.5%	1.2%
Service nights$^c$	20 min	14	0.3%	0.3%
Visitor instruments	20 min	23	0.2%	0.6%
$^a$ Assuming an average of 8 hr per night
$^b$ Excluding technical nights and visitor instruments
$^c$ Excluding service nights with SOFIN

This compares to a down time of 0.7% over all nights (0.6% on scheduled observing nights) in period 32. For that period 83 faults reports were submitted with an average time lost of 9 min per fault. Of these, 60 reported no time lost, 21 reported $<$ 2 hr lost, and 2 reported 2 or more hrs lost.

The most important thing to note is the continuing low down time. The down time is slightly higher than the all time low that was recorded in period 32, but the overall numbers for the fault reports (in particular the number of fault reports with significant amount of down time) are very similar indicating that this is a relatively stable situation.