Finely engraved disk carrying two telescopes, one swiveling on one side, the other fixed to the rim of the opposite side. Probably a finder system that belonged to a more complex instrument.

One side of the disk depicts twelve small putti. One holds the Sun, another an armillary sphere, another the Earth, and a fourth a disk with the French fleurs de lys. The two putti on the sides carry a shield, a royal crown, and two interlaced Ls. The remaining putti hold mathematical instruments. Provenance: Vincenzo Viviani bequest.