The Ujjain Observatory, located in the city of Ujjain, Madhya Pradesh, is widely regarded as the oldest astronomical observatory in the world. It was established around 500 BC and played a significant role in the development of Indian astronomy.

Ancient Indian observatories were primarily used for observing celestial bodies such as stars, planets, and the Moon. Astronomers used these observations to study the movements of these objects, predict eclipses, and develop calendars.

Aryabhata, a renowned ancient Indian astronomer and mathematician, is credited with developing the concept of the zero. His work on astronomy and mathematics had a profound impact on the development of these fields.

Jantar Mantar is an ancient Indian observatory located in Delhi, India. It was constructed by Maharaja Jai Singh II in the 18th century and consists of a collection of architectural instruments used for astronomical observations.

The Thanjavur Observatory was established by the Chola dynasty in the city of Thanjavur, Tamil Nadu. It was built in the 11th century and was used for astronomical observations and the development of calendars.

The Man Mandir Observatory is an ancient Indian observatory located in Varanasi, Uttar Pradesh. It was constructed by Maharaja Man Singh I in the 16th century and was used for astronomical observations and the development of calendars.

Bhaskara II, a renowned ancient Indian astronomer and mathematician, developed the theory of elliptical orbits for planets. His work on astronomy and mathematics had a significant impact on the development of these fields.

Jantar Mantar is an ancient Indian observatory located in Jaipur, Rajasthan. It was constructed by Maharaja Jai Singh II in the 18th century and consists of a collection of architectural instruments used for astronomical observations.

The Ujjain Observatory was established by the Gupta dynasty in the city of Ujjain, Madhya Pradesh. It was built in the 5th century and was used for astronomical observations and the development of calendars.

The Vedhshala Observatory is an ancient Indian observatory located in Mathura, Uttar Pradesh. It was constructed in the 16th century and was used for astronomical observations and the development of calendars.

Aryabhata, a renowned ancient Indian astronomer and mathematician, developed the theory of heliocentricism, which states that the Earth revolves around the Sun. His work on astronomy and mathematics had a significant impact on the development of these fields.

The Arappalli Observatory is an ancient Indian observatory located in Tiruchirappalli, Tamil Nadu. It was constructed in the 18th century and was used for astronomical observations and the development of calendars.

The Jantar Mantar observatory in Delhi was established by the Maratha Empire in the 18th century. It consists of a collection of architectural instruments used for astronomical observations.

The Kanchi Observatory is an ancient Indian observatory located in Kanchipuram, Tamil Nadu. It was constructed in the 12th century and was used for astronomical observations and the development of calendars.

Aryabhata, a renowned ancient Indian astronomer and mathematician, developed the theory of planetary motion. His work on astronomy and mathematics had a significant impact on the development of these fields.