The mater is wood with applied printed paper; the rete and plates pasteboard with applied printed paper; the fittings are brass.
The mater has a scale of hours on the limb, 0 to 12 twice in Roman numerals, divided to 1, subdivided to 4 minutes with alternate hatching, numbered by 1 hour; the same basic divisions are used also for an inner degree scale 90 to 0 to 90 to 0 to 90, divided to 5, subdivided to 1 with alternate hatching, numbered by 5. The printed decoration for the throne includes as head, above which is a brass shackle and suspension ring. Plank paper is applied to the rim. The inside of the mater is exposed wood.
The rete has 28 named stars connected by strapwork. The ecliptic has the names any symbols of the zodiacal signs, each with a scale of 30 degrees, divided to 10, subdivided to 5 and to 1 with alternate hatching, numbered by 10.
There are latitude plates for 39 and 42?; 45 and 48?; 51 and 54?; and 57? with nothing applied to the other side. The latitudes are given on the securing tabs as well as on the plates themselves. There are azimuths for every 5 degrees, numbered by 5 for 30 degrees on either side of the east and west points ion the horizon, and almucantars for every 2 degrees, numbered by 2 between 4 and 40. The horizon is marked 'Horizon Obliquus' twice, the east-west line 'Horizon Rectus' twice. Other marked lines are 'Tropicus Cancri', '?quinoctialis', 'Tropicus Capricorj' ('Capicornj' [sic] on the plate for 39 degrees, 'Capricor' on that for 51), and 'Linea Auror? siue Crepusculin?'. There are lines for equal hours, numbered 1 to 12 by 1, and divisions of the houses of heaven numbered 1 to 12 by 1.
The back has an outer degree scale 90 to 0 to 90 to 0 to 90, divided to 5, subdivided to 30 minutes with alternate hatching, numbered by 5 degrees. Inside this is a zodiacal scale with representations, names and symbols of the constellations, each with a 30-degree scale divided to 5, subdivided to 1, numbered by 5. There is an eccentric calendar scale with the names of the months and representations of seasonal activities, each with a scale of days, divided to 5, subdivided to 1 with alternate hatching, numbered by 1 as appropriate. In the upper half of the central area are two circular calendar scales of dominical letters and epact from 1583, marked 'Hoc Dorsum Kal[Ebar]dario reformato precise ac[obar]modatum est Per. J. Gosselinum custodem Regi? Bibliothec? Regis francor[ubar]'. In the lover half is a double shadow square with inner scales 0 to 12 to 0 to 12 to 0, divided to 3, subdivided with alternate hatching to 1, numbered by 3; and outer scales 0 to 60 to 0 to 60 to 0, divided to 5, subdivided to 1 with alternate hatching on alternate ranges of 60, numbered by 5. The scales are marked 'VMBRA VERSA', 'VMBRA RECTA', 'VMBRA VERSA'. Signed: 'PHILIPVS Danfrieus, Siderographus Regius Generalis Luteti? exarabat Anno Salutis 1584.'
Brass alidade with slit and pinhole sights, screw, wing nut and rule. Shaped, leather-covered wooden case.
See R. T. Gunther, The Astrolabes of the World (2 vols, Oxford, 1932), vol. 2, pp. 358-9.