Jantar Mantar is an astronomical observatory and equinoctial sundial located in the heart of Delhi. The name literally means “instruments for measuring the harmony of the heavens”.
Jantar Mantar dates back to the 18th century. It was constructed by Maharaja Jai Singh of Jaipur in 1724, to accumulate astronomical tables which would help in predicting the time and movements of celestial bodies such as the sun, moon and planets.
After constructing the Jantar Mantar in Delhi, Raja jai Singh had constructed more such structures by the same name in other places like Jaipur, Ujjain, Mathura and Varanasi.
And the observatory consists of many instruments which help predict these.
The 4 main instruments within the observatory are:
The Samrat Yantra, or the “Supreme Instrument”, is a giant triangle, and is basically an equal hour sundial.
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.
On either side of this triangle is a quadrant with graduations indicating hours, minutes, and seconds.
It acts as a precision tool for measuring declination and other related coordinates of various heavenly bodies. It can calculate the local time at an accuracy of up to two seconds and is considered the world’s largest sundial.
The Jaya Prakash Yantra consists of concave surfaces with hollowed out hemispheres with markings on them, and they have crosswires stretched between points on their rim. From inside it, an observer would be able to align the position of a star with various markings or a window's edge.
Jaya Prakash is one of the most versatile and complex instruments that can give the coordinates of celestial objects in multiple systems - the Azimuthal-altitude system and the Equatorial coordinate system, which allow for the easy conversation of the popular celestial system.
The Rama Yantra consists of two large cylindrical structures with open tops. It is used to measure the altitude of stars based on the latitude and the longitude on the earth.
The Misra Yantra (meaning “mixed instrument”) is a composition of 5 instruments designed as a tool to determine the shortest and longest days in a year. It is also used to indicate when it is noon in various cities all over the world.
The Jantar Mantar is a popular tourist destination in Delhi and is a great place for people who love astronomy. It is also a great place for children and students to learn about as
Jantar Mantar is open to public from 9.30 am till 5.30 pm every day, and people – that is Indian citizens, are charged an entrance fee of Rs.15 whereas foreigners or non-Indians may be charged up to Rs. 200.
Delhi’s Indira Gandhi International Airport is 15 km away from Jantar Mantar, and can be reached by taking the Delhi Airport Express metro (orange line) or hiring a cab from Jantar Mantar.
The closest metro station to Jantar Mantar is Patel Chowk. It can also be reached from Rajiv Chowk station which is only 5 minutes from the observatory.
Nearest Bus Stand to Jantar Mantar is Palika Kendra which is only 2 km away.
Some nearby attractions include Bible House, Regal Cinema and Metro Museum at Patel Chowk.