  ASTROSAT is an astronomy satellite designed for simultaneous multi-wavelength
studies in the Optical/UV and a broad X-ray energy range. With four X-ray
instruments and a pair of UV-Optical telescopes, ASTROSAT will provide
unprecendented opportunity for simultaneous multi-wavelength observations,
which is of immense value in study of highly variable sources, especially X-ray
binaries and Active Galactic Nuclei. The Large Area X-ray Proportional Counters
(LAXPC) of ASTROSAT, which has the largest effective area in the hard X-ray
band compared to all previous X-ray missions, will enable high time resolution
X-ray measurements in the 2-80 keV band with moderate energy resolution. Here
we give a brief summary of the payload characteristics of ASTROSAT and discuss
some of the main science topics that will be addressed with the LAXPC, and with
simultaneous observations with the UVIT telescopes, with particular emphasis on
X-ray binaries and compact objects. The possibility of aiding gravitational
wave experiments is also briefly mentioned.
