Regiomontanus dial for latitudes 0°-90° North. This instrument consists of a rectangular gilt-brass plate with a Regiomontanus dial on one side and an horary quadrant on the reverse. On the upper section of the obverse side is a trigon in which are drawn the zodiacal divisions crossed by horizontal parallels of latitude. Below the trigon, vertical hour-lines are drawn from 12 to 12. A decorated articulated arm is pivoted to the plate at the side of the trigon. It has a hole at its free end but the string, bead and bob are missing. Two pinhole sights are mounted at the top edge of the plate.

The quadrant, which can only be used in the latitude of 48° North, is marked with curving hour-lines drawn for 5am to 7pm. Around the edge is a combined calendar and zodiac scale. The equinoxes are marked for 20 March and 20 September. In the top right-hand corner is a hole from which a string carrying the brass indicator bead and plumb bob is suspended.

The quadrant is combined with an altitude quadrant so that heights of stars and of the sun can be taken. The floral decoration on the instrument is typical of French engraving.