The Rigveda, one of the four Vedas, contains hymns and verses that mention astronomical observations and theories. It includes references to celestial bodies, constellations, and the movement of the sun and moon.

Aryabhata, a 5th-century astronomer and mathematician, is regarded as the father of Indian astronomy. He made significant contributions to the field, including the development of the heliocentric model of the solar system and the calculation of the Earth's circumference.

Aryabhata proposed the theory of the Earth's rotation on its axis, challenging the prevailing geocentric model. He also calculated the length of the year with remarkable accuracy.

Jantar Mantar is an ancient Indian observatory built in the 16th century by Maharaja Jai Singh II. It consists of a collection of architectural astronomical instruments used for observations and calculations.

Brahmagupta, a 7th-century astronomer and mathematician, developed the concept of zero and the decimal system. He also made significant contributions to algebra and astronomy.

The Indian Space Research Organization (ISRO) is the national space agency of India. It is responsible for space exploration, satellite launch, and the development of space technologies.

Mangalyaan, also known as the Mars Orbiter Mission, was launched in 2013 to study the Martian atmosphere and search for evidence of past or present life on Mars.

Chandrayaan-1 was India's first lunar mission, launched in 2008. It successfully reached the moon's surface and conducted various scientific experiments.

Varahamihira, a 6th-century astronomer and astrologer, discovered the variable star Algol. He also wrote several influential works on astronomy and astrology.

Bhaskara II, an 12th-century astronomer and mathematician, developed the theory of planetary motion. He also made significant contributions to mathematics and astronomy.

Aryabhata calculated the value of pi (π) with great accuracy, approximating it to 3.1416.

Varahamihira wrote the influential work 'Surya Siddhanta', which contains detailed astronomical observations and theories.

Varahamihira developed the concept of the zodiac and the nine planets, which played a significant role in Indian astrology.

Aryabhata calculated the Earth's diameter with remarkable accuracy, approximating it to 12,742 kilometers.

Bhaskara II wrote the influential work 'Lilavati' on mathematics and astronomy, which covered topics such as arithmetic, algebra, and astronomy.