The MISRA or the COMPOSITE YANTRA, unique to New Delhi Observatory is composed of 5 different instruments, namely 1) DAKSHINNOTTARA BHITTI, 2) SAMRAT (in 2 halves), 3) NIYAT CHAKRA, 4) KARKA RASIVALAYA & 5) WESTERN QUADRANT.
It is believed to be constructed by Maharaja Madho Singh (1751-68), the son of Maharaja Sawai Jai Singh II.
Each 5 components have different functions.
Wikipedia article:
http://en.wikipedia.org/wiki/Jantar_Mantar,_DelhiCategory:
astronomy instrument