Clock-spring driven heliostat designed to observe the sun or sun-related phenomena, or to bring solar radiation into a laboratory setting. The spring driven clockwork slowly rotates a mirror so as to project a steady image of the sun on a target such as a screen or telescope. It was obtained from the inventory of the machine shop of the original Smithsonian Astrophysical Observatory and so likely dates from the late 19th century. Marked as a Keith Heliostat. Object was restored, including reconstructed parts based upon a complete example in the NMAH collection. PR&S staff at the Garber Facility performed the restoration.