Navgrahas
The life of an individual is guided by the charismatic movement of nine heavenly bodies known as planets or graham of the Solar system. Each of the Navagrahas represents 9 Planetary Gods in Hindu Religion. Hindus worship them as Gods. These 9 planets of Solar System are the Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn, Rahu and Ketu.
Sun is the central to all the planets and the entire nine planets move into its orbit. Out of the nine planet gods, seven are named after the names of the planets of the solar system and the other two gods are the names of demons who gained a place in the pantheon by a trick.
These planets and their position is the base of Hindu astronomy. Hindus firmly believe that the possibilities and potentialities of an individual depend upon planetary position at the time of a person's birth.
Basically we see navagrahas complementing main deities in some temple whereas some temples are exclusively meant to worship planet god only.