AstroSat is India's first dedicated multi-wavelength space observatory. It is aimed at studying celestial sources in X-ray, optical and UV spectral bands simultaneously. The payloads cover the energy bands of Ultraviolet (Near and Far), limited optical and X-ray regime (0.3 keV to 100keV). One of the unique features of AstroSat mission is that it enables the simultaneous multi-wavelength observations of various astronomical objects with a single satellite.
AstroSat with a lift-off mass of 1515 kg was launched on September 28, 2015 into a 650 km orbit inclined at an angle of 6 deg to the equator by PSLV-C30 from Satish Dhawan Space Centre, Sriharikota. The minimum useful life of the AstroSat mission is expected to be 5 years.
A number of astronomy research institutions in India, and abroad have jointly built instruments for the satellite. Important areas requiring coverage include studies of astrophysical objects ranging from nearby solar system objects to distant stars and objects at cosmological distances; timing studies of variables ranging from pulsations of hot white dwarfs to those of active galactic nuclei can be conducted with Astrosat as well, with time scales ranging from milliseconds to days.
There are five astronomy payloads for simultaneous multi-band observations:
* Twin 38-cm Ultraviolet Imaging Telescopes (UVIT) covering Far-UV to optical bands.
* Three units of Large Area Xenon Proportional Counters (LAXPC) covering medium energy X-rays from 3 to 80 keV with an effective area of 8000 sq. cm. at 10 keV.
* A Soft X-ray Telescope (SXT) with conical foil mirrors and X-ray CCD detector, covering the energy range 0.3-8 keV. The effective area will be about 120 sq. cm. at 1 keV.
* A Cadmium-Zinc-Telluride coded-mask imager (CZTI), covering hard X-rays from 10 to 150 keV, with about 6 deg field of view and 480 sq. cm. effective area.
* A Scanning Sky Monitor (SSM) consisting of three one-dimensional position-sensitive proportional counters with coded masks. The assembly is placed on a rotating platform to scan the available sky once every six hours in order to locate transient X-ray sources.
Missions
>> Simultaneous multi-wavelength monitoring of intensity variations in a broad range of cosmic sources.
>> Monitoring the X-ray sky for new transients.
>> Sky surveys in the hard X-ray and UV bands.
>> Broadband spectroscopic studies of X-ray binaries, AGN, SNRs, clusters of galaxies and stellar coronae.
>> Studies of periodic and non-periodic variability of X-ray sources.
Ground Control
The Ground Command and Control Centre for ASTROSAT is located at ISTRAC, Bangalore, India. Commanding and data download will be possible during every visible pass over Bangalore. Ten out of 14 orbits per day are visible to the ground station for long enough to accomplish full data download.
Images: Google, IUCAA