The Surya Siddhanta is an ancient Indian astronomical text that dates back to the 4th or 5th century CE. It contains detailed descriptions of various astronomical instruments, including the gnomon, the sundial, and the astrolabe.

Maharaja Jai Singh II was a renowned astronomer and mathematician who built five Jantar Mantars in India during the 18th century. These observatories were equipped with various astronomical instruments, including sundials, quadrants, and astrolabes.

Jantar Mantars were designed to serve multiple purposes, including measuring the time of day, observing the positions of celestial bodies, and predicting eclipses and other astronomical events.

The quadrant is an astronomical instrument that is used to measure the altitude of celestial bodies above the horizon. It consists of a quarter-circle arc with a plumb line attached to its center.

Sundials work on the principle of the Earth's rotation, the Sun's motion, and the Earth's tilt. The shadow of a gnomon (a vertical rod) cast on a dial plate indicates the time of day.

The Kodaikanal Observatory was established by the British in 1899. It is located in the town of Kodaikanal in Tamil Nadu, India.

Raja Rammohan Roy was the first Indian astronomer to use a telescope. He used it to observe the solar eclipse of 1836.

The Giant Metrewave Radio Telescope (GMRT) is the largest radio telescope in India. It is located near the town of Pune in Maharashtra, India.

The Giant Metrewave Radio Telescope (GMRT) is primarily used to study radio waves from celestial objects, such as galaxies, quasars, and pulsars.

The Thirty Meter Telescope (TMT) is the most recent astronomical instrument to be developed in India. It is a giant optical telescope that is currently under construction in Hawaii.

The Thirty Meter Telescope (TMT) is designed to study a wide range of astronomical phenomena, including the early universe, exoplanets, dark matter, and dark energy.

The Devasthal Optical Telescope (DOT) is the largest optical telescope in India. It is located in the town of Devasthal in Uttarakhand, India.

The Devasthal Optical Telescope (DOT) is designed to study a wide range of astronomical phenomena, including galaxies, quasars, exoplanets, dark matter, and dark energy.

The coronagraph is the most important astronomical instrument for studying the Sun. It is used to block out the bright light of the Sun's disk, allowing astronomers to observe the faint outer atmosphere of the Sun, known as the corona.

The Indian Astronomical Observatory (IAO) is primarily dedicated to the study of the Sun. It is located in the town of Hanle in Ladakh, India.