The Astronomical Observatories of Jai Singh c8.19

c8.19

The *Krānti Vṛtti Yantra* ('Ecliptic instrument'), found at Jaipur only, is quite a modern instrument, but is said to have been made according to Jagannāth's instructions; and there still is at Jaipur the old masonry work for a much larger instrument of the same type. The Krānti Vritti Yantra is used for direct measurements of celestial latitude and longitude. It consists of two brass circles (figure 58), pivoted so that one always moves in the plane of the equator and the other in the plane of the ecliptic. It is more suitable for demonstration purposes than for actual observation. (See page 51.) This is the Torquetum of Regiomontanus (1434-1476), which was rejected by Tycho Brahe as a clumsy instrument.¹