"S. P. SYBENGA, NORTH. SHIELDS"
radius 9.75 inches
This octant has an ebony frame, reinforced brass index arm, and ivory name
plate. The ivory scale is graduated every 20 minutes from -4o to +100o
and read by vernier and tangent screw to single minutes of arc. The
signature is that of Simon Peter Sybenga, an immigrant from Hamburg who worked
as a ship chandler in North Shields, England, from 1853 to 1871. The U.S. Navy
transferred this instrument to the Smithsonian in 1930.