Today I pulled the picture card from the camera facing the back meadow, and was very surprised by a sequence of photos taken two seconds apart. In the first, a deer is exiting the frame to the right, and a very bright and focused light appears on the ground like a beam of some sort, behind a large rock. In the second, only the deer is visible, so whatever it was, showed up and left quickly.
This area slopes down into the canyon and pond and there are no man-made structures nearby. If you have any ideas, please share.