Equinoctial dial

Equinoctial dial for latitude 30° North. This dial has a shaped brass base with three flower-headed levelling screws. At the centre of the base is a support for the vertical circle segment. At the North end of this, an equinoctial hour dial is held against the ring by a screw on which the numbers for every other hour are engraved in red. A screw on the South of the segment supports a horizontal compass. This has a white base marked with a red meridian line and a blued needle surmounted by a brass pyramidal pivot. A glass plate covers all. A screw at the top point of the segment supports a string plumb line and a brass plumb bob suspended over a brass pillar. A screw also supports the string gnomon which is perpendicular to the dial-plate.

This unusual form of equinoctial dial shows clear Western influence, as opposed to the 'pseudo-equinoctial' boxwood dials such as AST0378, AST0426 and AST0428.

For more information regarding this dial please refer to the OUP & NMM catalogue, 'Sundials at Greenwich'.