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

Varāhamihira, a renowned Indian astronomer and astrologer, is credited with establishing the Ujjain Observatory in the 5th century BCE.

The Jantar Mantar, a collection of astronomical instruments, was built by Maharaja Jai Singh II in the 18th century CE. It consists of five observatories located in different cities across India.

The Jantar Mantar was primarily used to study the movements of celestial bodies, such as the sun, moon, and stars. It allowed astronomers to make accurate observations and calculations related to astronomy.

The Nalanda Observatory was located in the city of Nalanda, which was a renowned center of learning in ancient India. It was established in the 5th century CE and was used for astronomical observations and studies.

Aryabhata, a renowned Indian mathematician and astronomer, is considered to be one of the most famous astronomers associated with the Nalanda Observatory. He made significant contributions to the field of astronomy, including the development of the Aryabhata system of astronomy.

The Takshashila Observatory was located in the city of Takshashila, which was a major center of learning in ancient India. It was established in the 5th century BCE and was used for astronomical observations and studies.

Brahmagupta, a renowned Indian mathematician and astronomer, is considered to be one of the most famous astronomers associated with the Takshashila Observatory. He made significant contributions to the field of astronomy, including the development of the Brahmagupta system of astronomy.

Ancient Indian astronomers made significant contributions to the field of astronomy, including the development of trigonometric functions, accurate measurement of the Earth's circumference, and the development of various astronomical instruments.

Aryabhata, a renowned Indian mathematician and astronomer, is credited with developing the Aryabhata system of astronomy, which was a significant contribution to the field of astronomy.

Brahmagupta, a renowned Indian mathematician and astronomer, is credited with developing the Brahmagupta system of astronomy, which was a significant contribution to the field of astronomy.

Aryabhata, a renowned Indian mathematician and astronomer, is credited with accurately measuring the Earth's circumference, which was a significant contribution to the field of astronomy.

Aryabhata, a renowned Indian mathematician and astronomer, is credited with developing the concept of zero, which was a significant contribution to the field of mathematics.

Aryabhata, a renowned Indian mathematician and astronomer, is credited with developing the decimal system, which was a significant contribution to the field of mathematics.

Aryabhata, a renowned Indian mathematician and astronomer, is credited with developing the concept of infinity, which was a significant contribution to the field of mathematics.