The observatory consists of fourteen major geometric devices for measuring time, predicting eclipses, tracking stars in their orbits, ascertaining the declinations of planets, and determining the celestial altitudes and related ephemerides. Each is a fixed and 'focused' tool. The Samrat Jantar, the largest instrument, is 90 feet high, its shadow carefully plotted to tell the time of day. Its face is angled at 27 degrees, the latitude of Jaipur. The Hindu chhatri (small domed cupola) on top is used as a platform for announcing eclipses and the arrival of monsoons.
Built of local stone and marble, each instrument carries an astronomical scale, generally marked on the marble inner lining; bronze tablets, all extraordinarily accurate, were also employed. Thoroughly restored in 1901.
An excursion through Jai Singh's Jantar is the singular one of walking through solid geometry and encountering a collective weapons system designed to probe the heavens.
The instruments are in most cases huge structures. They are built on a large scale so that accuracy of readings can be obtained. The samrat yantra, for instance, which is a sundial, can be used to tell the time to an accuracy of about two seconds in Jaipur local time.1 It is considered the largest sundial in the world. Today the main purpose of the observatory is to function as a tourist attraction.
From Wikipedia...
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Visit Instructions:Note the time of day of your visit, and your own photo of your favorite part of the observatory. This might be the view from the observatory, picture of your favorite building or favorite exhibit. (Be mindful of flash photography rules!)
If you participated in an observing session, let everyone know what you saw!