Equatorial sundial at Jaipur observatory, India, c 1728.
© Science Museum / Science & Society Picture Library
One of a series of models made between 1884-86, showing the astronomical instruments of the Jaipur Observatory, India. These were exhibited in 1886 at the Colonial and Indian Exhibition in London. Built of masonry, the Jaipur instruments were used to measure the position of the Sun, stars, moon and planets. Lacking telescopes, they relied upon naked eye sight and masive, but precise, construction. Known as a Samrat Yantra, this instrument was built and designed under the supervision of Maharajah Jai Singh II (b 1688). Finding European, Islamic and Hindu astronomical tables inaccurate, Singh decided to make his own observations to improve matters. As ruler of Rajastan, he built several observatories, beginning in 1724 with one near Delhi.