Triangle shaped craft over Westminster, CO

At approximately 12:50 AM I was outside trying to locate Jupiter when I witnessed 4 faint lights (3 at each point, 1 in the center), seemingly on 1 aircraft, flying overhead at a high rate of speed. All 4 lights moved in conjunction with one another, perhaps on a triangular shaped craft. It felt as if I could see through the object. The craft made absolutely no noise whatsoever and was moving southbound. After observing it for approximately 3 - 5 seconds the lights dimmed even further and it vanished.