Nocturnal

Combined nocturnal and sundial.
Latitude for sundial on reverse is that for central France. Possibly for Blois 47 deg 35 min N

For use with Little Bear. Bracket and suspension ring holds the compass. Compass is brass with cover, marked with cardinal points with engraved arrow for magnetic variation of 9 deg E of N.
Main disc: Date scale to named months. Zodiac scale anticlockwise. Hour scale clockwise subdivided to 15 min. Lunar age scale anticlockwise to 1 day
Rotatable disc with pointer: Has teeth and longer pointers at 12 hour line. Hour scale anticlockwise subdivided to 15 min. Circular aperture to reveal pictorial display of lunar phases
Pierced brass gnomon folding flat when not in use.

Object Details

ID: AST0119
Collection: Astronomical and navigational instruments
Type: Nocturnal
Display location: Not on display
Creator: Unknown
Date made: 17th Century
Credit: National Maritime Museum, Greenwich, London, Caird Collection
Measurements: Overall: 12 x 128 x 74 mm