This crudely engraved instrument, believed to be from Catalonia due to variations in the spelling and the shape of the engraved letter forms, is not a high precision instrument and may be a somewhat inelegant copy from an as yet unidentified astrolabe. Catalonia is the region where the Latin West was first introduced to the astrolabe, and probably where the first European astrolabes were constructed, in about 1000 AD.

The most striking feature of this instrument is the distinctive V-shaped frame inside the ecliptic of the rete. This type of rete is traditionally associated with the type of medieval English astrolabe generally identified as belonging to the tradition of Chaucer. Also noteworthy are the flame-shaped star pointers, usually associated with French astrolabes of the Louvain school. The throne of the astrolabe is cast in one piece with the limb, which is soldered to the mater. On the back of the instrument is an hour scale, calendar scale, a combined degree and zodiac scale and a shadow square. The alidade is a later addition (possibly 16th century), as is the rule.

There are seven unusually large original plates, all engraved on either side with a stereographic projection for a given latitude. On six of the plates, the name of the city for which the plate is intended is engraved just beneath the northernmost point of the horizon, together with its degree of latitude. For example: 'Barcelo-a' (41º), which is a Catalan form of 'Barcelona'.