Ram yantra in Jantar Mantar, Delhi Observatory
Ram Yantra in Jantar Mantar is the device used for measuring the altitude of stars. It is a cylindrical instrument, consisting of two large buildings open to the sky.
Jantar mantar is the astronomical observatory built by Maharaja Jai Singh II of Jaipur. It is also called Delhi Observatory and is located near Connaught Place, the state’s commercial centre.