Keywords: Gregorian reflecting telescope, Johann Gottlob Rudolph, Miltitz, c. 1748 - Mathematisch-Physikalischer Salon, Dresden - DSC07986.JPG en Exhibit in the Mathematisch-Physikalischer Salon Zwinger Dresden Germany This artwork is old enough so that it is in the public domain Photography was permitted in the museum without restriction 2013-12-08 07 15 00 own Daderot other versions PD-old-70 cc-zero Uploaded with UploadWizard Telescopes in Mathematisch-Physikalischer Salon Zwinger Dresden Johann Gottlob Rudolph Gregorian telescopes |