Equinoctial dial

Universal equinoctial dial for all latitudes. The dial comprises two hinged wooden leaves. The upper leaf contains a brass hour-circle with scales for northern and southern latitudes. A pivoted brass strut across the East-West diameter supports the rod gnomon. The compass is set into the lower leaf. It is displayed on a printed card with the cardinal and quadrantal points marked by English initials. The needle has a crosspiece to mark its North end and has a metal locking arm across the SE (for northern latitudes) radius of the compass. The latitude arm is set on the East (for northern latitudes) side of the lower leaf and is pivoted. It is divided from the tip 0°-90° and is locked to the upper leaf by a screw attachment. The dial is held closed by two brass hook fasteners and when the dial is closed, the upper leaf presses against a small brass pin, which activates the locking mechanism of the compass.

This is one of the few instruments in the collection (other than the universal equinoctial ring dials) that can be used for northern and southern latitudes. Not only are there two hour scales, but the compass card is also marked for the two hemispheres. This suggests that it was intended for use by someone who travelled widely throughout the world, and it is certainly small enough to be easily portable. A very similar instrument is in the MHS in Oxford (new inventory no. 37012). The compass card is signed 'STEWARD 406. STRAND'.

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

Object Details

ID: AST0422
Collection: Astronomical and navigational instruments
Type: Equinoctial dial
Display location: Not on display
Creator: Steward, J. H.
Date made: 1850-1900
Credit: National Maritime Museum, Greenwich, London
Measurements: Overall: 21 x 57 x 59 mm

Your Request

If an item is shown as “offsite”, please allow eight days for your order to be processed. For further information, please contact Archive staff:

Tel: (during Library opening hours)

Click “Continue” below to continue processing your order with the Library team.