Plate has 4 mounting holes and is set with a double gnomon with 5 attachment screws. Plate is hand divided and incorporates a stereographic projection of the celestial sphere onto the observer's horizon plane. Line of equal altitudes radiates from vertical gnomon. Arcs of equal declination plotted between the tropics, crossed by hours lines, and with ecliptic path of sun superimposed. Brass badly oxidized and inscriptions barely visible.
