The armillary sphere rests on a modern wooden stand. A support of four quadrants rises to the horizon ring.
The horizon line is engraved with the names of the 12 main winds in Latin and Greek, 'MEZOGIORNO', 'SIROCCO', 'LEVANTE', 'GRECO', 'TRAMONTANA', 'MAESTRO', 'PONENTE', 'GARBINO' on an inner circle and the others on an outer circle. It is engraved with a scale of degrees divided to 1 degree, numbered in four quadrants from 10 to 90 with 90 on the meridian line. The meridian ring is engraved with a scale of degrees divided to five and to 1 degree by alternate shading, numbered from 10 to 90 by 10 with 90 at the pole. The inner system of rings has solostitial and equinoctial colures, with a scale of degrees divided to 5 and to 1 degree on two quadrants by alternate shading, numbered from 10 to 90 by 10. The equator ring is covered by the ecliptic band, which has been incorrectly assembled possibly later, two tropic rings and arctic and antarctic circles. The two colures carry 6 star pointers which are named. The tropic of cancer ring is divided to 5 and to 1 degree, on two opposite quadrants by alternate shading, and is numbered in four quadrants from 10 to 90 by 10. The arctic circle is divided to 1/4 hour by alternate shading, numbered from 1 to 24 by 1. The ecliptic band is engraved with a zodiac scale, divided to 5 and 1 degree by alternate shading in two opposite quadrants, numbered from 10 to 30 by 10, and with the symbols and names of the signs engraved. It is also engraved with a calendar scale, divided to 1 day by alternate shading in only two quadrants, numbered by 10 from 10 to the last day of the month as appropriate. The names of the months are also engraved. The first point of Aries is at 10 March. The equator ring, of which only the inner edges are visible, is engraved with the symbols of the zodiacal signs. The inner rings carry the sun and the moon. The earth is fixed to the centre by a diametral axis, which is now tilted but which corresponds to the celestial poles.
On the lower part of the horizon line is the date and signature 'Romae a<nn>o 1578 Car. Pl'.