Green lights in Chevron form flying over Fort Collins, CO.I was letting my roommate's dog outside, when I saw a group of fluorescent green lights in the form of a chevron. This was observed a few minutes after 23:30 MST approximately 4 blocks south of CSU Fort Collins campus. The event lasted for 5 to 10 seconds. It was a clear night with no clouds, stars were visible. I was the only witness who saw this. I am a senior at Colorado State studying Civil Engineering and have a good understanding of physics, optics, and trigonometry.There were 5 to 7 lights in the formation, and were first seen 20 to 30 degrees above the horizon. I was looking south when I first sighted them, and watched them move north almost directly overhead; they were 20 degrees from vertical to the east of me. As the chevron passed over head, it started accelerating and gaining altitude, before the lights disappeared 40 to 50 degrees above the horizon looking north. The lights were observed for a total of 100 to 120 degrees in the sky. As the lights passed from south to north, they changed shape from a chevron into a straight line. I live on a N-S-E-W street grid, and I can determine that the lights were traveling within 10 degrees of the N-S axis.From the observation point, the lights appeared relatively small, but much larger than a star. The individual lights were round, with a hazy edge and appeared to be about 1/6 the size of the moon. The chevron formation had a span of 3 moons, and stayed approximately this size for the entire duration, as they changed shape. As the object passed overhead, it made no sounds. The dog I was letting out did not respond to the event.((NUFORC Note: We spoke via telephone with the witness, and we found him to be eloquent, and sober-minded. In part, because of his technical training, we suspect he is a very capable witness. He has submitted a very nice graphic, which illustrates the sighting, and which is posted to the NUFORC website. PD))