AstroSat
Topic: Remote Sensing, GIS and GNSS · NCERT: Beyond NCERT
Meaning
AstroSat is India's first dedicated astronomy satellite. ISRO launched it in 2015. It points away from the earth and studies stars, galaxies and black holes. It can observe in X-ray, optical (visible light) and ultraviolet bands at the same time, so it is a multi-wavelength observatory. Its UltraViolet Imaging Telescope (UVIT) was built by the Indian Institute of Astrophysics (IIA), Bengaluru. AstroSat was designed to work for about five years, but it completed a decade in orbit in September 2025. ISRO made its archival data (stored past observations) public on 26 September 2018 through its ISSDC portal. Scientists anywhere can now download and study this data.
Example
AstroSat's UVIT has photographed the Small and Large Magellanic Clouds. These are two nearby galaxies that the Milky Way is slowly pulling in, and they are seen in the southern sky. Ultraviolet light comes mostly from young, hot stars, so these images show where new stars are forming in the Clouds.
Don't confuse with
- IRS / Cartosat / RISAT (earth observation satellites): these look down at the earth for remote sensing of crops, land, water and disasters. AstroSat looks out into space.
- XPoSat (launched 1 January 2024): this satellite mainly measures X-ray polarisation, which is the direction in which X-ray waves vibrate. AstroSat is a general observatory that covers several wavelength bands.