Combined nocturnal and horary quadrant.
This is the earliest known work by Eufrosino della Volpaia and one of the earliest scientific instruments to be signed and dated by the maker.

Technical details:
For use with Little Bear, not Great Bear
Obverse: Two rotatable discs rather than one.
Main disc: Named months on date scale subdivided to one day. Meridian transit (lowest point) at 14 October.
Lower rotatable disc: Pointer marked MIDIA NOX (Midnight) and hour scale subdivided to 10 minutes
Upper rotatable disc: Pointer (marKed 24) and teeth numbered 1 to 15 anticlockwise from pointer. Inside this is a table of Italian hours at midnight throughout year for latitudes 42 and 43 deg. The inner scale lists months.
Pointer: Shaped end. Reverse has horary quadrant for Italian hours. Degree scale divided anticlockwise 0 - 90 deg numbered by 5 deg and subdivided to 1 deg. Midday marked by arc towards right of quadrant and hour-lines drawn to the left with continuous arcs for morning hours and dotted arcs for afternoon hours running fairly straight down the quadrant. Lines parallel to circumference indicate declination parallels and are marked with a date scale. Top part of quadrant is a circular table with three scales; a zodiac scale, a months scale, and an inner scale with 12 letter markings. Quadrant has a hole at its vertex. There is a pattern round the edge of the disc.
The handle has been broken off with only attachment to reverse of disc remaining.