Learn about Sun and Moon through heritage around us

Built by Maharaja Jai Singh II of Jaipur, the Saffron coloured Jantar Mantar rests in the heart of the Capital since 18th century but only a handful of people know of it as an astronomical observatory.

To commemorate 100 years of Delhi as the Capital and 150 years of Archaeological Survey of India (ASI), a walk was organised to inform people about the science behind Jantar Mantar which comprises four yantras or instruments and was built to know the position of the Sun, the Moon and the planets. Organised by Space - an NGO, the walk for the attendees turned out to be more than just a visit to an archeological site.

C B Devgun, President, Space acquainted those present with scientific and practical aspects of the observatories and how they worked when it came to telling local time; time in other countries; and Sun’s position in India and other countries.

“Samrat Yantra, the largest and the most imposing one among the four was used to measure the accurate time of the day and motion of the Sun in the sky. The yantra was used as a Sundial to determine the time using position of the Sun and its shadow on the yantra,” informed Devgun.

Jai Prakash Yantra, another important structure consists of two concave hemi-spherical structures used for ascertaining the position of the sun and time, especially at night. The structure was designed by Maharaja Jai Singh himself.

Another structure called the Ram Yantra consists of two open circular structures with a central pillar. These two are used to determine the altitude and azimuth - meaning angular measurement of the Sun.

The last one is Mishr Yantra, which looks similar to the shape of a paan leaf. It was meant to determine the shortest and longest days of the year and also the Sun’s position in other countries. 

More than the technical details of these instruments, what amazed the participants was how ancient astronomers studied motions of the sun, moon and planets without the help of any high tech satellites or telescopes, and told time without clocks.

Jantar Mantar, meaning instrument and formula, is one of the five similar astronomical observatories built by Maharaja Jai Singh.

Besides Delhi, Jantar Mantar was also built in Jaipur, Varanasi, Ujjain and Mathura. “The one in Jaipur has been maintained very well. More or less they are same, except that the Jaipur observatory has some more yantras,” said Devgun. “There are many historical monuments in Delhi which have scientific value and are of architectural importance. We are planning more such walks at other monuments like Qutub Minar to familiarize people with them,” he said.