The mater of this astrolabe has no limb. One face is calibrated for a latitude of 48?, corresponding to Munich.
On the back are a zodiacal calendar, a division into days and a specific calendar. At the centre is a small slot containing a latitude plate bearing the divisions of the months and days, a division according to the zodiac and other indications, as well as a zodiac planisphere.
The astrolabe, which is extremely accurate, is unsigned, but has been attributed to Hans Dorn, who was active in Germany at the end of the 15th century.