The Ujjain Observatory, located in the city of Ujjain, is believed to have been established around the 5th century BCE and is considered to be the oldest known astronomical observatory in the world.

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

The primary purpose of the ancient Indian observatories was to study the movement of stars and planets, enabling astronomers to gain insights into their positions, orbits, and patterns.

The gnomon, a simple yet effective instrument, was widely used in ancient Indian observatories to measure the altitude of celestial objects and determine the time of day.

The Nalanda Observatory, located in the ancient university town of Nalanda, was renowned as a center for astronomical research and education, attracting scholars from across the world.

Aryabhata, a brilliant astronomer and mathematician, developed a mathematical model known as the Aryabhata system, which allowed astronomers to calculate the positions of the planets based on their mean positions and velocities.

Maharaja Jai Singh II, a keen astronomer, constructed a series of observatories known as Jantar Mantar in various cities across India, including Delhi, Jaipur, Ujjain, and Varanasi.

The Ujjain Observatory is situated in the city of Ujjain, which is located in the state of Madhya Pradesh, not Maharashtra.

The Takshashila Observatory, located in the ancient city of Takshashila, was primarily used for observing the movement of stars and planets, contributing to the development of astronomical knowledge in ancient India.

Bhaskara II, a renowned astronomer and mathematician, proposed a theory of planetary motion that incorporated elliptical orbits, providing a more accurate representation of the actual motion of planets.

The Jantar Mantar observatories were primarily designed for observing celestial events, such as the position of the sun, moon, and stars, and for measuring time accurately.

Maharaja Jai Singh II constructed one of the Jantar Mantar observatories in the city of Varanasi, along with other cities like Delhi, Jaipur, and Ujjain.

Aryabhata, a brilliant astronomer and mathematician, developed a method for calculating the circumference of the Earth, demonstrating his remarkable understanding of astronomy and mathematics.

Maharaja Jai Singh II constructed one of the Jantar Mantar observatories in the city of Jaipur, which is located in the state of Rajasthan.

The primary focus of the astronomical research conducted at the ancient Indian observatories was to study the movement of stars and planets, enabling astronomers to gain insights into their positions, orbits, and patterns.