Lambana and Nati



Lambana, (latitudinal parallax ) and Nati (longitudinal parallax ) are both forms of geocentric parallax. The idea describes why an object, like the moon, looks to be at a different place on the celestial sphere, depending on where one is on the Earth. The fact must be taken into account when performing astronomical calculations.

It is caused by the fact that the Earth is rather large, and some objects (the moon especially) are rather close to the Earth, relative to the distance of the sun and the distant stars. This is especially true for eclipses. One person might not see an eclipse, while another would, simply because of geocentric parallax.

Some early Indian astronomers used the word Lambana. Bhāskara II discusses one of Brahmagupta's calculations and points out an error in the parallax of latitude of the Moon.

Lalla, in his, describes both Nata and Lambana , and uses the concept to refute the notion that eclipses were cuased by Rahu devouring the sun. He pointed out that not everyone on the Earth sees an eclipse, and thus it was hard to explain how the sun could have been eaten.