History of the Jantar Mantar

• The history of Jantar Mantar traces the history of astronomical interest of India. The Jantar Mantar is an astronomical observatory in Delhi constructed by King Sawai Jai Singh II in 1724.

• Jai Singh built four other such observatories in Jaipur, Ujjain, Mathura and Varanasi.

•  It was called the Yantra Mantra and was the result of Sawai Jai Singh’s passion for astronomy related subjects.

• The primary purpose of the observatory was to compile astronomical tables, and to predict the times and movements of the sun, moon and planets.

• Jantar Mantar sculptural structures inspired contemporary art and architecture. In 2008 Tatiana Bilbao designed the Observatory House in collaboration with the artist Gabriel Orozco, who visited Jantar Mantar astronomical observatory in 1996.

The complex of Jantar Mantar includes:

• Samrat-Yantra- It is an equinoctial (equal hour) sun dial, which comprises of a triangular gnomon. The hypotenuse of the gnomon is parallel to the earth's axis. Either side of the gnomon is attached with a quadrant of a circle, which is parallel to the plane of equator. It is 70 feet high, 114 feet long at the base, and 10 feet thick. It has a 128-foot-long (39 m) hypotenuse that is parallel to the Earth's axis and points toward the North Pole. 

• Ram Yantra- It consists of two large buildings with open top. Both these two buildings form a complete device. The device is used to measure the altitude of stars which is equivalent to the latitude and the longitude on the earth.