Astronomy
T1
In ~5th-century India, the Surya-Siddhanta encoded the sidereal year — the time the Sun takes to return to the same star — as 365.2587 days. Modern instrumentation puts it at 365.25636. Off by 3.5 minutes; ~7 parts per million accuracy. Pre-telescopic. Ptolemy's contemporaneous Almagest missed by 14 minutes — four times the Surya-Siddhanta error.
From the source
“Of the moon, fifty-seven million, seven hundred and fifty-three thousand, three hundred and thirty-six ”
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Featured in 4 articles
- The Roman Siddhānta: Greek astronomy inside the Indian canon (505 CE)
Published July 5, 2026
- One second per month: the Sūrya-Siddhānta's lunar orbit
Published July 5, 2026
- A globe in the ether: the Sūrya-Siddhānta on why there is no 'up'
Published July 5, 2026
- The Surya-Siddhanta knows the length of the year — to within 3.5 minutes, pre-telescopic
Published May 25, 2026