21 March – 21 June 2016 in Florence, Rome, Naples, Palermo, Padua

REFRACTING TELESCOPE

Steinheil (objective), Munich 1858

brass, wood, glass

objective: 108 mm diameter, 1620 mm focal distance

INAF-Arcetri Astrophysical Observatory, inv. Coll. Scient. e Museali n. 107005001

This telescope was purchased in autumn 1858 by the German lithographer Ernst Wilhelm Leberecht Tempel; it was initially equipped with a wooden tube and an especially crafted wooden mount, designed by Tempel and made in Venice at the beginning of 1859. From that year, Tempel used the telescope for his astronomical observations in Venice, Marseille and Milan. With it, Tempel discovered the Pleiades nebula, 5 asteroids and 11 comets, among which C/1864 N1, the first comet to have been observed spectroscopically by Donati (see Fi. 04). Tempel brought this instrument with him when he moved to the Arcetri Observatory in 1875. After his death in 1889 the telescope was bought by the Observatory. The wooden tube was replaced with a brass one, and from the 1920s the instrument was used as a finder and guidance telescope for the Amici Equatorial. The instrument was restored in 2008 and mounted on a wooden tripod kindly provided by the INAF Turin-Astronomical Observatory (the original mount being lost). The optical characteristics of the objective lens are identical to those of the Fraunhofer telescope used by Donati for his solar spectroscopic observa- tions.

Bibl.: ABETTI 1901, BIANCHI ET AL. 2009, 2010.