Red light off coast of Maine.Four of us were outside on a deck, looking at the unobstructed night sky, when a circular red light in the distance started moving back and forth at apparently great speeds. It began to make 45 degree turns before returning to its original position in the southeast, off the coastline of Maine. After watching it for about 10 minutes, the light suddenly vanished and did not reappear there or elsewhere in the sky. I'm not very good at judging distances but I would guess it was about three miles off the coast, and about 5,000 feet from the ground.