This picture captures number etched on one of the solar instruments at Jantar Mantar, a UNESCO World Heritage Site in Jaipur. Marble stone surface has numeric marking etched over it. The number etched is in Hindi script reading 13.
The reading on Rasivalaya Yantra is taken with help of shadow created by the Sun. There are twelve such instruments each representing the signs of zodiac and measures current latitude and longitude of the celestial body.
Jantar Mantar Jaipur History
Between 1724 and 1727 AD, Maharajah Sawai Jai Singh II, founder of Jaipur city built solar observatories in five North Indian cities. Out of all these five, the solar observatory in Jaipur is the most elaborate one. It’s being claimed that Jantar Mantar in Jaipur completed in 1734 AD. All instruments at Jantar Mantar are in working condition. They still work with the same precision.
What is Jantar Mantar?
Jantar means instrument and Mantar means calculation, so it implies instrument of calculation. Maharajah Jai Singh II was a great mathematician and had a keen interest in astronomy, which led to building of Jantar Mantar. Drawing from the knowledge of Persian, Arabic and Portuguese astronomy, these were one of its kind solar instruments built anywhere else.