Kapala Yantra (Small Prakash Yantra)

 astronomy, instruments

Twin bowl instruments that are a reflection of the sky. The instrument on the east is for measurement while the instrument on the west is for theoretical usage to convert from one kind of celestial co-ordinates into another.
These instruments, named Kapala Yantras, were built side by side on a masonry
platform. Named Kapala A and Kapala
B, the two hemispheric bowls have very
different functions. Kapala A has engravings similar to the Jai Prakash, but lacks
the cutaways and size that would permit
night observations. Kapala B serves only
to transform graphically the horizon system of coordinates into the equator system
and vice versa. It is the only instrument at
Jaipur not meant for observing.( Source :www.jantarmantar.org/Architecture_Science_web.pdf)

Link to Quicktime virtual tour of the Kapala Yantra: www.jantarmantar.org/JaipurTour_2.html