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Proposal Statistics
Timo Prusti
Please, note that figures referenced here are in a single file of 225KB.
The following statistics were collected just before PDEC closed to visitors. The Phase 2 data entry was approaching its end with 99% of observations having been entered at PDEC, and IPAC proposals having been included in the archive. Figures 1 to 4 show the distribution of observing time per instrument and per observing mode. In each case, the distribution is expressed firstly in terms of number of observations, and secondly by observing time.
The average length of an observation is 23.5 minutes. However, the facility to force two or more observations to be carried out back-to-back (``concatenation'') has been used rather extensively. Instead of 22500 observations, the mission planning has to deal with just over 10000 observation chains. This leads to a 47.0 min average observing block. Due to the skewness of the observation duration distribution, the median length of an observing block settles down to 29.5 min. Distributions are shown in figures 5 and 6.
Figure 1. ISO Instrument usage by number of observations
Figure 2. ISO Instrument usage by time
Figure 3. Number of observations per observing mode
Figure 4. Total time per observing mode
Proposers have requested that a total of over 2000 observations be carried out at particular specified times (referred to as ``fixed time observations''). Based on current estimates, executing all of them might lead to a significant loss of overall observing efficiency. Currently, a more detailed study is being performed.
Figure 5. Distribution of number of observations against time for observations less than 1 hour
Figure 6. Distribution of the number of observations against time for all observations
K. Leech
ISO Resident Astronomer
August 1995
Tue Oct 3 19:21:38 MET 1995