A large bright round light, darting across the sky, after 10 minutes - the light just went out.I often watch the stars, we have an beautiful large view facing south off the Grand Mesa. I had mentioned to my husband that at any given time of day or night, there would be a minimum 3 planes in the sky view. Traffic from Denver to Salt Lake City etc. This was not a plane. I saw a round light through the first of three large panes of glass in my bedroom. I thought what a bright star, huge. I watched, it seemed to be moving, so I thought satelite. No, this was skirting left, up, down & right not dramatically but noticeably. It was in the distance, how far I don't know but close enough to see the back and forth movements. I watched it cross to the second pane of glass, still bright. No flashing lights like a plane, of which there were three I could see in the same sky area. It wasn't consistant moving like a statelite would very high in the sky. This was a bright round moving light. As it entered the third pane of glass, I woke my Husband to ensure someone else could see this. He did, very clearly and he saw the darting motion...then poof ! It disappeared, we both gasped and confirmed what we saw. It didn't drop, or speed away, the light went out - poof.