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GALILEO GALILEI

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Galileo's telescope [2]

Inv. 2428 V.2 Galileo's telescope c. 1609-1610 Galileo Galilei Wood, leather Length 980 mm

Description Original telescope of Galileo consisting of a main tube at the ends of which are inserted two separate sections with the objective and the eyepiece. The tube, formed by strips of wood joined together, is covered in red leather (which has become brown with the passage of time), with gilt decoration. The plano-convex objective, with the convex side towards the outside, measures 37 mm in diameter, has an aperture of 15 mm, focal length 980 mm and thickness at the centre 2.0 mm. The original eyepiece has been lost and has been replaced in the nineteenth century by a biconcave eyepiece of 22 mm in diameter, thickness at the centre 1.8 mm, and focal length -47.5 mm (the negative focal length means that the lens is diverging). The instrument can enlarge objects 21 times and has a field of view of 15'. This Galilean telescope is registered in the 1704 inventory of the Uffizi Gallery as "A telescope of Galileo 1 2/3 braccia long [973 mm] in two pieces to lengthen it, covered in leather in many colours and gilt decoration, with two lenses, of which the eyepiece is inclined": the eyepiece therefore was still extant, but was free in the tube. Since the end of the eighteenth century all trace of the original eyepiece lens has been lost. Prince Federico Cesi, founder of the Accademia dei Lincei, in 1611 proposed calling this instrument "telescopio" [from the Greek tele (far) and scopeo (I see)].