Observed a triangular shaped filmy patch of light moving from east to west at 5:15 am north of Ione, OR, which moved at a constant speedWe observed a triangular shaped patch of moderately bright, white light moving from east to west. It had semitransparent, filmy appearance as opposed to being a opaque object. We first observed it in Cygnus in the eastern sky. It had moved about 2/3 of the way to the western horizon in about 15 min. In size it was about the area of a quarter held at arm's length. It looked somewhat like the constellation Pleiades but much brighter. It appeared to be a fan emanating from a bright point of light on its left (south) side. The object was still visible as it passed from our viewing range.We are retired farm couple who were enjoying our predawn hot tub.((NUFORC Note: Sighting of launch of Delta IV rocket from Vandenberg AFB. PD))