Flickering light in a stationary position for close to 20 minutes in the Western sky from PA.

Unmoving bright flickering light in the Western sky. Originally thought to be a plane, then helicopter. However, FL was too high for helicopter. Next though it was a planet or bright star with some sort of atmospheric effect that would cause flickering. With hands cupped around eyes to reduce light pollution, it appeared to have a sort of "eclippse" effect. Like there was something behind the light. A different dark 'color' than the night sky? It's tough to explain. Could have just been my eyes playing tricks, but I've never seen anything like it and I was an air traffic controller for nearly 7 years.