Down Time

The down time statistics are based on individual fault reports. In Table 1 I give the general down time statistics for period 29.

A total of 77 fault reports were submitted, with an average time lost of 15 min per fault, for a total down time of 1.3% (1.6% on scheduled observing nights). Of these, 64 reported no time lost, 11 reported $<$ 2 hrs lost, and 2 reported 2 or more hrs lost.

Table 1: Technical down time statistic period 29: 2004-04-01 to 2004-10-01

Night included	Time lost	Nights	Percentage$^a$	Last period
All nights	1140 min	183	1.3%	1.7%
Scheduled observing nights$^b$	1040 min	132	1.6%	2.6%
Technical nights	30 min	25	0.3%	0.9%
Service nights$^c$	45 min	9	1.0%	%
Visitor instruments	70 min	26	0.6%	0.3%
$^a$ 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 1.7% over all nights (2.6% on scheduled observing nights) in period 28 (2003-10-01 to 2004-04-01). For that period 63 faults reports were submitted with an average time lost of 29 min per fault. Of these, 37 reported no time lost, 24 reported $<$ 2 hr lost, and 2 reported 2 or more hrs lost.

Comparing the two periods the one thing to note is the decrease in faults causing down time. In fact, the number of faults causing down time and the total amount of down time for period 29 are the lowest over the past few years.