SITE PLAN of the JAIPUR JANTAR MANTAR
(ASTRONOMICAL OBSERVATORY)
(From "Archaeological Survey of India, New Imperial Series 40,
The Astronomical Observatories of Jai Singh" by G.R. Kaye, 1918, Calcutta)

　 1   Brihat Samrât Yantra (Giant Equatorial Sun-Dial)
　 2   Râshi Valâya Yantra (Twelve Zodiac Ins.)
　 3   Jai Prakâsh Yantra (Armillary Sphere)
　 4   Kapâla (Hemispherical Bowl Instrument)
　 5   Chakra Yantra (Equatorial Instrument)
　 6   Râm Yantra (Altitude/Azimuth Instrument)
　 7   Digamsha Yantra (Azimuth Instrument)
　 8   Kranti Writta (Equatorial Sunｰdial)
　 9   Lâghu Samrât Yantra (Small Equatorial Sun-Dial)
　10   Nari Valâya Yantra (Hemispherical Sun-Dial)
　11   Astrolâbe (Astro Calculator)
　12   Unnatamsha Yantra (Altitude Instrument)
　13   Maharaja Jai Singh's Seat
　14   Dakshino Vritti Bhitti Yantra (Meridian Wall Instrument)

The direction of walls encircling the site is about 15 different degrees from that of instruments, because the shape of the site was restricted by city axes (road grids) regardless of the desirable due north and south axis of astronomical observation instruments. When Jai Singh planned the city of Jaipur (whether following ancient Vast Vidya's description or not), he must have wanted to set the city axis being north-south but was obliged to move it 15 degrees clockwise to adapt the city to the configuration of the land. It resulted in the gap between the city axis and instruments' axis.