Fast moving white object zig zags across lake stops beside tree top (orange saucer) for a short time then shoots into sky.

The object came into view over Lake Magog as I stood past the end of a row of cottages and street lights.  As I faced the lake waiting for my friend to get a flashlight I saw a bright white light zigzag across from the far end of the lake and then cross to my left over the land and stop instantly directly in front of a tall pine tree about 3 feet from its tip to my left across the road.  Had it not stopped I think it would have hit the tree.  
It sat perfectly still and that is when I could see it was a saucer shape of a light yellow orange-ish glow.  I though it might have 'noticed' me and was observing me.  
After maybe 25 to 30 seconds of sitting there it zigged to the side of the tree then moved at a ninety degree angle to the side and shot into the sky at about a 50 degree angle moving very fast.  Just a guess but at least several hundred miles per hour until disappearing from sight.
We spoke at length via telephone with the witness, and he seemed to us to be quite eloquent and sober-minded.  The date is taken from a diary, so probably is accurate.  PD