Varahamihira, a renowned astronomer and astrologer, is often recognized for introducing the concept of the zodiac and the 12 zodiac signs in Indian astronomy.

The Nakshatra Samvat is an ancient Indian calendar that is based on the lunar cycle. It consists of 12 months, each of which is associated with a specific nakshatra (lunar mansion).

Aryabhata, a brilliant astronomer and mathematician, proposed the theory of the Earth's rotation on its axis, contradicting the prevailing belief of a stationary Earth.

The astrolabe was an important instrument used by ancient Indian astronomers to measure the positions of celestial bodies. It allowed them to determine the time, latitude, and longitude.

Aryabhata, a renowned mathematician and astronomer, calculated the value of pi (π) to four decimal places, demonstrating his exceptional mathematical skills.

The Vikram Samvat is an ancient Indian calendar that is based on the solar cycle. It is widely used in India and Nepal and is named after the legendary king Vikramaditya.

Bhaskara II, a renowned astronomer and mathematician, developed the theory of the elliptical orbits of planets, challenging the prevailing belief of circular orbits.

The quadrant was an instrument used by ancient Indian astronomers to measure the altitude of celestial bodies above the horizon.

Aryabhata, a brilliant astronomer, proposed the existence of a heliocentric model of the solar system, where the Earth and other planets revolve around the Sun.

The Panchang is an ancient Indian calendar that is based on the combination of the lunar and solar cycles. It is widely used in India for various religious and astrological purposes.

Brahmagupta, a renowned astronomer and mathematician, developed the theory of the precession of the equinoxes, which explains the gradual shift in the position of the equinoxes over time.

The sundial was an instrument used by ancient Indian astronomers to measure the time of day based on the position of the Sun.

Varahamihira, a renowned astronomer and astrologer, proposed the existence of a geocentric model of the solar system, where the Earth is the center of the universe.

The Shaka Samvat is an ancient Indian calendar that is based on the sidereal year, which is the time taken for the Earth to complete one orbit around the Sun relative to the fixed stars.

Aryabhata, a brilliant astronomer, developed the theory of the motion of the Moon, explaining its elliptical orbit and its relationship with the Earth.