We arrived at Jantar Mantar and paid our 100 rupee entry fee. At least the differential between the local and tourist price was only 5x in this instance.
We hired a fixed price guide to take us around and explain the sights of Jantar Mantar. Built by Maharaja Jai Singh II in the early 1700s, this was an impressive collection of astronomical instruments. By far, the most striking instrument was this extremely large sundial accurate to 20 seconds.
Many of the instruments were composed of two hemispheres with spaces in between to aid accuracy of measurement (allowing the person doing the measurement to get up close to get a reading).
Each zodiac sign was represented by a carefully spaced sundial.
It felt quite hot in the sun with very little shade available. After about an hour exploring, we took one last look at the signature sundial and headed on our way.