Down Time

The down time statistics are based on individual fault reports. In Table 1 I give the general down time statistics for period 30.

A total of 84 fault reports were submitted, with an average time lost of 16 min per fault, for a total down time of 1.2% (0.9% on scheduled observing nights). Of these, 58 reported no time lost, 24 reported $<$ 2 hrs lost, and 2 reported 2 or more hrs lost.

Table 1: Technical down time statistic period 30: 2004-10-01 to 2005-04-01

Night included	Time lost	Nights	Percentage$^a$	Last period
All nights	1340 min	182	1.2%	1.3%
Scheduled observing nights$^b$	735 min	141	0.9%	1.6%
Technical nights	560 min	23	4.1%	0.3%
Service nights$^c$	225 min	11	3.4%	1.0%
Visitor instruments	45 min	20	0.4%	0.6%
$^a$ Assuming an average of 10 hr per night
$^b$ Excluding technical nights and visitor instruments
$^c$ Excluding service nights with SOFIN

This compares to a down time of 1.3% over all nights (1.6% on scheduled observing nights) in period 29. For that period 77 faults reports were submitted with an average time lost of 15 min per fault. Of these, 64 reported no time lost, 11 reported $<$ 2 hr lost, and 2 reported 2 or more hrs lost.

Comparing the last few periods the general thing to note is that there are little changes in the overall down time. The main difference with last period is that the 2 main problems occurred on a technical and a service night, respectively, which caused the down time for technical and service nights to be rather high. The down time during schedule observing time is the lowest ever reported.