The Three Suns were the trio of stars which Thra orbited. They consist of the Greater Sun, the Rose Sun and the Dying Sun. Eclipses between the suns are referred to as "Conjunctions;" an eclipse between any two suns is called a Lesser Conjunction, but an eclipse between all three is called a Great Conjunction, which is noted to resemble an eyeball when viewed from directly beneath. While the frequency of Lesser Conjunctions is not stated, a Great Conjunction occurs once every thousand trine. A Conjunction of any from will project a beam of Energy into Thra's Crystal, which depending on the conjunction in question can be utilized for a number of purposes.
According to Podling folklore, the Three Suns were brothers who once fought over the daughter of the moon. When she drowned herself out of grief, the three brothers would do battle every nine hundred and ninety nine and one trine.