Yantra Chintamani – SineQuadrant (sinecal) to measure celestial angles, time, find directions, determine the positions of celestial object. Made by Hrsikesa, 18th Century Astronomer.

Source: – @othisaivu / Twitter.

YantraChintamani – SineQuadrant (sinecal) to measure celestial angles, tell time, find directions, determine the apparent positions of any celestial object for any time. Made by Hrsikesa, 18thCentury Astronomer. Nagari, Arabic markings. https://t.co/U8Z9dC1rGz pic.twitter.com/CtSwyKazbT

— othisaivu (@othisaivu) December 12, 2017

The story of the Indian positional, mathematical Astronomies and Trigonometry: The sine quadrant was described for the first time in Sanskrit by Padmanābha,
who also wrote a manual on a special kind of astrolabe in 1423. pic.twitter.com/0kYqSRCKPp

— othisaivu (@othisaivu) December 12, 2017

YanthraRaja: King of [astronomical] instruments; name given to Astrolabe in India. c18thCentury. Nagari markings. https://t.co/Si2VU8SZ8l pic.twitter.com/w8tCX6le32

— othisaivu (@othisaivu) December 12, 2017