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Telescope time statistics for the last three winters

This winter more than one observer at the 30m telescope had the (unpleasant) experience of loosing almost all his oberving time because of bad weather. There has been an unusual amount of rain and snow in the last few months, partly compensating for the drought of the last years (some observers may remember the cut of water supply in the Granada residencia). What was appreciated by the organizers of the ski world championship and in general by people in Andalucía, didn't really make astronomers happy. The statistics in Fig. 1 compares the fractions of telescope time used for observations in the winters (December to March) 1993/94, 1994/95, and 1995/96. Fig. 2 shows the time distribution for each winter. Usually, almost 70% of the telescope time are used for observations, and about 20% lost due to bad weather and wind (this also corresponds roughly to the yearly averages of 1994 and 1995). This winter, however, more than twice the time (47%) was lost because of bad weather, and only 42% of the time was used for observations. Thus, more time was lost than used! Even in these 42% of used time, a large fraction was probably not good weather for bolometer observations, and some data may not be usable (the time is marked as ``used for observations'', when the observer records data, not taking into account the data quality).

Figure 1: Distribution of 30m telescope time for the last two and present winter. More than twice the time has been lost this winter because of bad weather and wind.