The double refractor was built by
Mailhat, Paris, in 1904. The visual instrument (the lower of the two tubes) has an aperture of 38 cm and a focal length of 6 meters (f/15.8). The photographic instrument also has an aperture of 38 cm, but a shorter focal length of 4 meters (f/10.5). File:Fabra Observatory Refractor.jpg|Mailhat telescope File:Telescopi Mailhat de l'Observatori Fabra 02.JPG|Mailhat
refractor from 1904 File:Fabra Observatory, Barcelona.jpg|Fabra Observatory on the hill above the metropolis == See also ==