What appeared to be 3 normal stars began to move in perfect formation, then faded from view.

While looking up at the stars, a friend and i both noticed at about the some time that a few stars appeared to be moving.  We pointed them out to the third person there and watched as the stars continued to move in a large isosoles triangle formation.  The formation was much larger than any plane could have been, even if it was at low altitude-the formation was approx. half the area of the inside of the little dipper, which is where we first spotted it.  the object continued to move at a fairly good clip, at one point obstructing the view of another stationary star, until it faded from view.
((ADDENDUM FROM VIGILANT READER))
See forwarded images for Heaven's Above satellite track and other data to show the NOSS triad disappeared at 23:17 and passed through the Little Dipper. 
NOSS 2-3 (C) and (D) and (E)
USSPACECOM Catalog No.: 23908
International Designation Code: 1996-029-C
Observer's Location: Littleton ( 39.6130°N, 105.0160°W)
                      Starts                      Max. Altitude            Ends
Date      Mag  Time         Alt. Az. Time        Alt. Az.     Time Alt. Az.
 08 May  6.0  23:08:48   10  NW  23:16:13  88  WSW  23:17:35  65  SSE
((END))
Witness elects to remain totally anonymous.  PD