Journey
Observatories & the meridian
Sawai Jai Singh II built five masonry observatories in the 1720s and 1730s, at Delhi, Jaipur, Ujjain, Mathura and Banaras, because he did not trust the accuracy of brass instruments. He wanted bigger ones, so he built them out of stone — the largest sundial in the world is accurate to about two seconds.
Stops (5)
- Jantar Mantar, Delhi · Delhi — the first, 1724
Jai Singh's earliest observatory, built for Muhammad Shah, with the Samrat Yantra sundial, the hemispherical Jai Prakash and the Misra Yantra that can determine noon in several cities at once. He had compared Ptolemaic, Islamic and Hindu tables against each other, found them all disagreeing, and concluded that new observation was needed.
- Jantar Mantar, Jaipur · Jaipur — the largest, 1734
Nineteen instruments including the Vrihat Samrat Yantra, a sundial twenty-seven metres high and accurate to about two seconds, and twelve rāshivalaya instruments each aligned to one zodiacal sign, which exist nowhere else. It is the most complete of the five and the only one still usable as built.
- Ujjain observatory (Vedh Shala) · Ujjain — building on the meridian
The Vedh Shāla stands where Indian astronomy had placed its prime meridian since at least Varāhamihira's time, so Jai Singh's instruments were sited on a line already fifteen centuries old. Ujjain also lies close to the Tropic of Cancer, which is why the tradition treated it as the reference point for the subcontinent's longitudes and calendars.
- Konark Sun Temple · Konārk — the temple as instrument
Twelve pairs of carved wheels with eight major and eight minor spokes, which can be read as a sundial: the shadow of a spoke's axle against the rim gives the time. Whether that was intended or is a later reading is disputed, but the temple's orientation to catch the equinox sunrise on the sanctum is not in doubt.
- Modhera Sun Temple · Modherā — the equinox alignment
Built about 1026 with the sanctum placed so that the rising sun at the equinoxes falls the length of the axis onto the image, and with a stepped kunda in front holding a hundred and eight subsidiary shrines. Getting that alignment right required exactly the kind of observational astronomy the texts describe.