I had just left work after 11:30pm. on Thurs. 1/15 when driving east down rte. 62 in Danvers I noticed a bright object in the southern sky. I first said to myself it had to be a plane as Logan Intl. is only about 8 miles from where the object was, but i did see a plane near the object. As I started heading east on rte. 128N the object started moving ahead of me moving in a N/NE. I lost sight of it on my left side, then a minute or two later it was to my right. I then decided to follow it all the way to the end of the highway into Gloucester and went straight to the ocean and stopped my truck. I obseverved the object now stopped and hovering near Thatcher island which is right off the coast of Rockport. It was just hovering there moving slightly erraticly and seemed like it was moving closer to me. I then drove down the coastline to see if I could get a closer look. I was now even closer to the island and it just hovered and moved around in kind of a circular motion. Glowing brighter and shimmering. It was about 5 degrees out and barely any cloud cover. I watched it for about a half hr. between both places. I couldn't stay and watch all night because I had to get up early that morning. I Then left and I wanted to see if I could see it again before I went home. I went to Good Harbor Beach which is about a half mile from the island, and it was hovering high over the beach. I would say about 2000-5000ft.