Replica of German rectangular horary quadrant, 1549

Electrotype copy of a rectangular horary quadrant with shadow dial scale by George Hartmann, Nuremburg, Germany and dated 1549.

Dated 1549, this electrotype copy of rectangular horary quadrant was made by George Hartmann in Nuremberg, Germany. This reverse view shows extra timekeeping scales. The horary quadrant was used for finding local time by sighting either the Sun or a bright star at night. Held vertically, a measurement could be taken from the position on the scale of a moveable bead on the thread of the instrument's plumb bob. The instrument was derived from the astrolabe and first appeared during the Medieval Period. Like its predecessor it includes a two-dimensional depiction of the heavens that is reduced to a quarter.