Very bright pulsing light in northern sky, moving slowly to NE in a side to side up and down and zigzag fashion.A very bright light, flashing, pulsing colors purple, blue white has beem observed by myself and my husband off and on from 7/27/02 to present in the northern sky moving gradually from the northwest to the northeast over a period of hours. It moves up. down and side to side and zig zag. It hovers and then glides slowly in a kind of dance. It appears always in the north but at different times of the night. It seems as if it may be masquerading as a star, hover and moving very slowly so as not to be noticed by a quick glance skyward.As for my background, I am a retired college professor of Literature.((NUFORC Note: We suspect a celestial body may have been the cause of the sighting. We have invited the witness to look again in the same area of the sky, at approximately the same time, to see if the object is visible again. We also suggested a star chart. PD))