Ujjain meridian (prime meridian of Indian astronomers)
Meridiano de Ujjain (primer meridiano de los astrónomos indios)
- Date
- c. 500 · confidence low
- Place
- Ujjain, Madhya Pradesh, India
- Credited to
- Astronomers of the Siddhantic tradition (Aryabhata, Varahamihira)
- Field
- Cosmos & Earth
⚠️ Disputed: the sources disagree.
What it is
In classical Indian astronomy longitudes were reckoned from a meridian running through Lanka, on the equator, and through Ujjain. That meridian fixed the tables of times and positions of the Siddhantic texts for centuries.
The texts (Pancasiddhantika, Surya Siddhanta) date from the 5th-6th centuries and later; Lanka is a conventional point on the equator, not the present-day island, and the exact formulation varies between authors.
What it led to
- astronomical tables comparable between places in India
- a tradition of longitude calculation independent of the Greek one