How old is Indian Astronomy? Did it exist even before the discovery of the Solar System?
Yes, it is the oldest. Seven celestial bodies were known since Vedic times to move faster than the background of the stars: the Sun, Moon, Mercury, Venus, Mars, Jupiter, and Saturn. At some point, knowledge also developed of the nodes of all the planets (see the citation of Arybhata I below, under Ancient Indian Astronomers). The nodes are those points where a planet or the Moon crosses the ecliptic (the Earth’s orbital plane around the Sun) going north or south of the ecliptic. The North Node is the point where a planet or Moon crosses from south of the ecliptic to north of the ecliptic. The South Node is the point where a planet or Moon crosses from north of the ecliptic to south of the ecliptic. When the Moon crosses the ecliptic at the same time the Sun is visible, there will be an eclipse. Knowledge of the Moon’s Nodes is reasonable evidence of an understanding of eclipses in ancient cultures. The Vedas have a special name for the Moon’s North Node (Rahu) and the Moon’s South Node
