4. Aspects of duplication
The general policy of the ASTROSAT is to avoid repeating the same observation, i.e. to avoid duplications.
In general, a duplication is determined by consideration of the target coordinates and of the main observing parameters (especially the instrument (s) and the observing modes). A proposed observation duplicates another one if the expected science data are essentially the same or of lower requirement (e.g. lower exposure time) and is therefore discouraged. It is, however allowed, to observe the same target with the same instrument configuration several times for variability studies. In addition, in large extended objects several pointings in the vicinity of a source may become necessary e.g., to image Coma Cluster of galaxies out to 2 deg. diameter so as to cover its virial extent, and these may have co-ordinates that are not too different from that of the previous observation of a source.
The responsibility for defining and resolving cases of duplication rests with the ATAC in consultation with the Principal Investigator, AstroSat as needed. The ATAC can allow duplications between a proposed observation and an observation of a previous cycle. These should be restricted to proposals which provide convincing evidence that additional data are of scientific relevance.