Malcolm Reed points out a blue giant to navigate by in 2151.
A blue giant is a type of star.
In 2151, without navigational sensors, Malcolm Reed attempted to pilot a stranded Shuttlepod 1 by setting a course based on a blue giant they had passed. (ENT: "Shuttlepod One")
In 2152, Enterprise NX-01 set course for a blue giant cluster sustaining several non-inhabited planets. (ENT: "The Communicator")