Navgrahas, or Navagrahas, are the nine heavenly bodies that have the power to influence upon life on the earth. Nav means ‘nine’ and Graha means ‘the one that grasps you or in whose influence you are possessed.’ It must be noted that Graha does not mean a planet in the modern sense. But the term planet is widely used to describe the Nava Grahas. In strict sense, 
Navagrahas are the nine influences over the life of human beings.
The Navgrahas are Sun (Surya), Moon (Chandra or Soma), Mars (Mangal), Mercury (Budh), Jupiter (Brihaspati or Guru), Venus (Shukra), Saturn (Shani), Rahu and Ketu.
Navgrahas are installed in Hindu temples as subsidiary deities and there are also temples dedicated exclusively to Navagrahas.