Ultra Violet Imaging Telescope (UVIT) is one of the payloads on the first
Indian multi wavelength satellite ASTROSAT expected to be launched by Indian
Space Research Organisation (ISRO) in the year 2015. We have performed
simulations of UV studies of old open clusters for the UVIT. The colour
magnitude diagrams (CMDs) and spatial appearances have been created using 10
filters of FUV channel (130 - 180 nm) and NUV channel (200 - 300nm) available
for observations on the UVIT, for three old open clusters M67, NGC 188 and NGC
6791. The CMDs are simulated for different filter combinations, and they are
used to identify the loci of various evolutionary sequences, white dwarfs, blue
stragglers, red giants, sub giants, turn off stars and the main sequence of the
clusters. The present work helps in identifying the potential area of study in
the case of three old open clusters, by considering the availability of filters
and the detection limits of the instrument. We also recommend filter
combinations, which can be used to detect and study the above mentioned
evolutionary stages. The simulations and the results presented here are
essential for the optimal use of the UVIT for studies of old open clusters.Comment: Accepted for publication in RAA; 25 pages, 19 figures, 1 tabl
