The phrase "pole star" refers to a bright star that is almost directly above the Earth's North or South Pole. It helps people find their way by acting as a fixed point in the night sky. Full definition
When toward the end of his life he was awarded the prestigious Wolfgang Amadeus Mozart Prize, von Balthasar referred to Mozart as the «immovable pole star» around which circled Bach and Schubert («the Great and Little Bears»). (religion-online.org)
The Coen Bros return to the 1950s (Barton Fink, The Man Who Wasn't There, The Hudsucker Proxy) to recount a batty tale of a Hollywood fixer and a tent - pole star gone missing. (silverscreenriot.com)
An achiever who explains can be your pole star. (kpcb.com)