Nocturnal. Folding diptych with nocturnal on upper leaf inside and instructions for use on inside of lower leaf. Corners of leaves protected by metal corner-pieces. Yellow paper with blue printing used inside.
Nocturnal: Fixed disc with floral motifs in the four corners around it, and rotatable disc and pointer.
Fixed disc: Date scale divided anticlockwise to named months, numbered and divided to 5 days. Meridian transit (lowest point) at 1 July.
Rotatable disc: Hour scale divided anticlockwise subdivided to 15 min. Three pointers for Big Dipper, Little Dipper and Cassiopeia.
Pointer: Central hole with brass lining. Index arm for alignment with the pointer stars of the Big Dipper.