My family and I went onto the roof of our home to do some stargazing at about 9pm. My wife and I saw a dull black/grey triangular shaped craft (against the dark moonless night sky) with a dim light placed near each corner. It was at quite a low altitude and was moving at a fairly low speed. We observed this craft for nearly a minute. I used to be Army Aviation and am very familiar with many types of aircraft in the world. I said, "That's not a plane...." And we watched it slowly proceed south/southwest until it was out of sight.