Only the mater remains of this astrolabe. The rim is engraved with a scale of degrees divided to 5 and to 1 degree, numbered in four quadrants from 10 to 90 with 90 at the zenith. Common hours are also numbered on the same scale from 1 to 12 twice.
The back of the mater is engraved with a scale of degrees on the rim, divided to 10, to 5 and to 1 degree, numbered in four quadrants from 10 to 90 with 0 at the zenith. The central part of the plate is engraved with a Rojas projection. The position and names of 12 stars are engraved, as are the symbols of the zodiacal signs. The ecliptic line is engraved 'Ecliptica'. The meridians are engraved every degree and the hours are numbered from 1 to 12 and engraved 'Hore ante meridiem' and 'Hore post meridiem'. The poles are engraved 'Polus arcticus' and 'Polus antarcticus'.
Suspension is by ring, shackle and throne and the throne is in simple scroll shape. The ring and pin are in iron.