Hemisferium Hartmann's Planispherical Astrolabe 15∅This planisferic astrolabe is set for 50 latitude. This Plansiferic Astrolabe is based on an instrument made by German manufacturer called Georg Hartmann which can be found in The British Museum, London. In 1518, Georg Hartmann, also known as Georgius Hartman, settled in Nuremberg, where he developed his vast oeuvre. By 1523, Hartmann was at the head of a prolific and successful workshop that specialized in scientific instruments, including sundials,