The object sighted was very faintly luminous and vee shaped, and was observed on Dec 13, 2017, approximately 9:45 at night, local time. My brother and I had stepped outside into my back yard in Mountain View, AR, to watch for meteors from the Geminid meteor shower. The sky was very clear, and dark enough to see the Milky Way. The air was cold and quite dry. After about 10 or 15 minutes, long enough to have become somewhat dark adapted we saw a moving object almost directly overhead (tree limbs would have interfered earlier.) The object was barely visible with direct vision, slightly more clear with averted vision. It was vee shaped, not a filled in triangle, and was moving with its point forward in the direction of motion. If you extended your thumb and forefinger, then extended your hand out to arm's length, each side of the vee was about as long as your thumb, and the angle of the vee about the same as thumb and forefinger; I would say more than 60 degrees but smaller than 90 degrees. Surface brightness of the object was only slightly brighter than the Milky Way. The actual width of each arm relative to the vee was quite small. I would estimate each arm width at perhaps one tenth the arm length. There were no individual lights, just the same faint luminous glow down each arm of the vee. The vee was moving from overhead (where it was first sighted) toward the south east at a moderate but steady speed such that it passed from overhead to about 45 degrees above the SE horizon in about 15 seconds. After another 5 seconds or so it seemed to dim and disappear in another second or so. There was no audible sound during its passage. While we had been watching it move across the sky I saw it move past a star. The star was clearly visible inside the vee shape as the object moved over it, so I can definitely say that it appeared to be strictly a vee, and not a full triangle with a glowing front edge. While I have no way of knowing what the actual dimensions of the object were, or at what height it was moving, it seemed to be at a relatively low altitude, may one or two thousand feet (but that is just my subjective felling about it.) My brother and I both discussed what we had seen and agreed that we had seen pretty much the same thing. My brother has better eyesight than I do and did not see any extra details. I will say also that I am an amateur astronomer with about 50 years of observing objects in a night sky. Had the night not been very clear and black, and had we not had a chance of being dark adapted, we would never have seen this low brightness object. Over some decades I have seen some very interesting things in the sky, but this is the first time I have seen anything like this, or anything that I could not ultimately identify. This one is a real puzzle.