The Ujjain Observatory, also known as the Vedhshala, is believed to be the oldest astronomical observatory in India, dating back to the 5th century BCE.

Varahamihira, a renowned Indian astronomer and mathematician, is credited with establishing the Ujjain Observatory in the 6th century CE.

Ancient observatories in India served multiple purposes, including astrological predictions, timekeeping and calendar making, and observing celestial events.

The armillary sphere, a spherical model of the universe, was widely used in ancient Indian observatories to measure the positions of celestial bodies.

The Jantar Mantar in Jaipur is renowned for being the largest stone observatory in the world, built by Maharaja Jai Singh II in the 18th century. It comprises 19 architectural astronomical instruments for various observations.

Aryabhata, a prominent Indian astronomer and mathematician, proposed the heliocentric model of the solar system in the 5th century CE, centuries before Copernicus.

Bhaskara II made significant contributions to ancient Indian astronomy, including developing the concept of zero, calculating the value of pi, and formulating trigonometric identities.

The Ujjain Observatory gained fame for its precise predictions of eclipses, which were crucial for religious and astrological purposes.

The Nalanda Observatory was a prominent center of astronomical studies in ancient India, housing a vast library of astronomical texts and nurturing renowned astronomers.

The Takshashila Observatory was closely linked to the renowned Takshashila University, a center of higher learning in ancient India.

The sundial was primarily used in ancient Indian observatories to measure the time of day based on the position of the sun.

Brahmagupta, a renowned Indian astronomer and mathematician, made significant contributions to spherical trigonometry, developing formulas and methods for solving problems related to spherical triangles.

The quadrant was primarily used in ancient Indian observatories to measure the altitude of celestial bodies above the horizon.

The Ujjain Observatory was renowned for its detailed observations and studies of planetary motion, contributing to the understanding of planetary orbits and positions.

The astrolabe was a versatile instrument used in ancient Indian observatories for measuring the altitude of celestial bodies, determining the time of day, and observing the movement of stars.