Museo Galileo
Virtual Museum
Repeating circle
    • Setting:
      Room XIV
    • Maker:
      Georg Friedrich von Reichenbach
    • Place:
    • Date:
      first half 19th cent.
    • Materials:
      brass, bronze
    • Dimensions:
      length 1330 mm
    • Inventory:
    • Repeating circle (Inv. 576)

Instrument made in the workshop of Georg Friedrich von Reichenbach with an objective signed by Fraunhofer. It consists of a telescope rotating on the horizontal and vertical axes. The angles of rotation on the horizontal axis (altitude angles) can be measured with high precision (1/10 of a minute) by means of the repetition system. The instrument is supported by a bronze column rotating freely on its vertical axis. The lower end of the column rests on the base. The upper end moves in a socket fixed to a supporting beam. In this particular instrument, the upper beam rests on two wooden pillars. The angles of rotation on the vertical axis were measured by means of a graduated circle, still complete, while the system for reading the graduations on the circle is missing. The pillar carries a vertical brass circle engraved with a finely graduated scale for measuring the altitude angle, but the system is incomplete. To facilitate measurements, the telescope is fitted with an eyepiece allowing lateral observation. There are also two counterweights and a set of lever systems to offset the bending of the tube under its own weight.