The Ujjain Observatory, located in the city of Ujjain, Madhya Pradesh, is the oldest astronomical observatory in India. It was built in the 5th century BCE by the astronomer and mathematician Aryabhata.

The Jantar Mantar in Jaipur, Rajasthan, is known for its unique architecture. It consists of a series of jantar mantras, which are instruments used for astronomical observations. These instruments were built by Maharaja Sawai Jai Singh II in the 18th century.

The Kashi Observatory is located in the city of Varanasi, Uttar Pradesh. It was built in the 18th century by Maharaja Sawai Jai Singh II. The observatory consists of a series of instruments used for astronomical observations.

The Ujjain Observatory is known for its association with the astronomer and mathematician Aryabhata. Aryabhata was the director of the observatory in the 5th century BCE. He made significant contributions to the field of astronomy, including the development of the heliocentric model of the solar system.

The Delhi Observatory is located in the city of Delhi. It was built in the 19th century by the British. The observatory was used for astronomical observations and meteorological studies.

The Ujjain Observatory is known for its association with the astronomer and mathematician Varahamihira. Varahamihira was the director of the observatory in the 6th century CE. He made significant contributions to the field of astronomy, including the development of the lunar calendar.

The Mathura Observatory is located in the city of Mathura, Uttar Pradesh. It was built in the 18th century by Maharaja Sawai Jai Singh II. The observatory consists of a series of instruments used for astronomical observations.

The Ujjain Observatory is known for its association with the astronomer and mathematician Bhaskaracharya. Bhaskaracharya was the director of the observatory in the 12th century CE. He made significant contributions to the field of astronomy, including the development of the sine table.

The Hyderabad Observatory is located in the city of Hyderabad, Telangana. It was built in the 19th century by the British. The observatory was used for astronomical observations and meteorological studies.

The Khajuraho Observatory is known for its association with the astronomer and mathematician Madhava of Sangamagrama. Madhava was the director of the observatory in the 14th century CE. He made significant contributions to the field of astronomy, including the development of the power series expansion of trigonometric functions.

The Madras Observatory is located in the city of Chennai, Tamil Nadu. It was built in the 19th century by the British. The observatory was used for astronomical observations and meteorological studies.

The Khajuraho Observatory is known for its association with the astronomer and mathematician Nilakantha Somayaji. Nilakantha was the director of the observatory in the 15th century CE. He made significant contributions to the field of astronomy, including the development of the trigonometric identities.

The Kolkata Observatory is located in the city of Kolkata, West Bengal. It was built in the 19th century by the British. The observatory was used for astronomical observations and meteorological studies.

The Ujjain Observatory is known for its association with the astronomer and mathematician Jagannatha Samrat. Jagannatha was the director of the observatory in the 17th century CE. He made significant contributions to the field of astronomy, including the development of the astronomical tables.

The Mumbai Observatory is located in the city of Mumbai, Maharashtra. It was built in the 19th century by the British. The observatory was used for astronomical observations and meteorological studies.