One of a pair of coloured aquatints produced by T & W Daniell in 1808, showing the Samrat Yantra sundial at the old observatory at Delhi, India. This masive device was built and designed under the supervision of Maharajah Jai Singh II (1686-1743). Finding European, Islamic and Hindu astronomical tables inaccurate, Singh decided to make his own observations to improve matters. As ruler of Rajasthan, he built several observatories starting in 1724 with one near Delhi. Built of masonry, the Delhi instruments were used to accurately measure the position of the Sun, stars, Moon and planets. In the absence of telescopes, these devices used naked eye sights and masive, but precise construction.
© Science Museum / Science & Society Picture Library