Very long pale green rectangle, high up, moving from West towards slight Southeast, mostly East. Vanished slowly while maintaining course and speed.
In a clear, dark sky I was alerted to motion in my peripheral vision and noticed something moving through the tree line at the edge of a field where as many as 200 people were camping. My mind attempted to make me believe it was an evaporating vapor trail for about two seconds, until it cleared the Northwestern tree line and I could see that it had hard edges and was pale green. It was as plain of a rectangle as you could imagine, and was very long and thin. It traveled Eastward, with a very slightly Southeast trajectory as I and as many as seven other people watched it for nearly a minute. When it was due North from our location, it simply faded from view as it continued its course and speed unchanged. There was no other observable lights or aircraft about, other than stars. There was no sound. Just a glowing green rectangle crossing the sky.