A quadrant is a period astronomical instrument used for measuring elevation from the horizon. It consists of a graduated quarter-circle (hence the name) with a movable index and a sight; an example with heraldic interest is a horary quadrant engraved with the badge of Richard II, 1399 [Marks & Payne 35]. For related charges, see astrolabe, sphere, sundial.
Iosif of Novgorod bears: Sable, on a bend sinister embattled counter-embattled argent between in chief three estoiles and in base a quadrant Or, a scarpe gules.
Christoforo Antonio Passavanti bears: Sable, a quadrant Or.
Gosfrei Kempe bears as a badge: Or, a quadrant gules.