The basic arrangement of the Earth
Laṅkā was a legendary city thought to be on the equator, directly south of the city of Ujjain.  It was one of the cities through which passed the prime meridian (longitude 0) of Vedic astronomy.
Laṅkā is frequently used in writings that describe the nature of the celestial sphere, by way of imagining how the rotation of the Sun and stars would appear to someone located at Laṅkā. 
- ↑ Template:Ref-indian-astronomy, APPENDIX IV
- ↑ Template:Refia4.3.2
- ↑ Template:Refia4.5.2
- ↑ See for example section 4, especially around 4.15, 4.16. Template:Refia