The Ujjain Observatory, also known as the Vedhshala, is the oldest known observatory in India. It was built in the 5th century BCE and was used by ancient Indian astronomers to study the positions and movements of celestial bodies.

The Jantar Mantar is an astronomical observatory built in the 18th century by Maharaja Sawai Jai Singh II. It consists of a collection of architectural instruments that were used to measure time, track the movement of the sun and stars, and predict eclipses.

The Jantar Mantar is known for its large collection of astronomical instruments, including sundials, quadrants, and astrolabes. These instruments were used to make accurate measurements of the positions and movements of celestial bodies.

The Vainu Bappu Observatory is located in Kavalur, Tamil Nadu. It is operated by the Indian Institute of Astrophysics and is known for its research in optical astronomy and astrophysics.

The Giant Metrewave Radio Telescope (GMRT) is located near Pune, Maharashtra. It is known for its studies of radio waves from space, including observations of pulsars, galaxies, and cosmic microwave background radiation.

The Indian Astronomical Observatory (IAO) is located in Hanle, Ladakh. It is operated by the Indian Institute of Astrophysics and is known for its studies of solar physics, infrared astronomy, and gamma-ray astronomy.

The Indian Astronomical Observatory (IAO) is known for its studies of solar eclipses. The observatory has been used to observe and study several total solar eclipses, including the one that occurred in 2019.

The Aryabhatta Research Institute of Observational Sciences (ARIES) is located in Nainital, Uttarakhand. It is operated by the Aryabhatta Research Institute of Observational Sciences and is known for its studies of astronomy and astrophysics.

The Tata Institute of Fundamental Research Cosmic Ray Observatory (TIFR-CRPO) is located in Ooty, Tamil Nadu. It is operated by the Tata Institute of Fundamental Research and is known for its studies of cosmic rays, including observations of high-energy particles and their interactions with the Earth's atmosphere.

The Devasthal Optical Telescope (DOT) is located in Devasthal, Uttarakhand. It is operated by the Aryabhatta Research Institute of Observational Sciences and is known for its studies of optical astronomy and astrophysics.

LIGO India is located in Hanle, Ladakh. It is a part of the Laser Interferometer Gravitational-Wave Observatory (LIGO) project and is known for its studies of gravitational waves, including observations of the merger of black holes and neutron stars.

The Vainu Bappu Telescope (VBT) is located in Hosakote, Karnataka. It is operated by the Indian Institute of Astrophysics and is known for its studies of optical astronomy and astrophysics.

The Kodaikanal Solar Observatory (KSO) is located in Kodaikanal, Tamil Nadu. It is operated by the Indian Institute of Astrophysics and is known for its studies of the Sun, including observations of sunspots, solar flares, and solar prominences.

The Pachmarhi Observatory is located in Pachmarhi, Madhya Pradesh. It is operated by the Aryabhatta Research Institute of Observational Sciences and is known for its studies of astronomy and astrophysics.

AstroSat is a space observatory launched by the Indian Space Research Organisation (ISRO). It is known for its studies of gamma-ray bursts, X-ray astronomy, and optical astronomy.