An important Kepler or Keplerian telescope, called astronomical telescope, made of turned ivory, cardboard and green vellum, and kept in its splendid black morocco case decorated with numerous gilded decorations, and lined with pink silk.
The telescope, unsigned, is French and datable from the middle of the 18th century, i.e. from the Louis XV period.
The fixe telescope are no draw. It measures 19.3 cm in length.
This telescope has a Keplerian optical composition, giving an inverted image, but has a third field lens. This additionnal and very rare lens allows to use the telescope on both eyepiece and objective side to achieve two magnifications of different power.
Despite some accidents to the original lenses, the telescope gives a clear, sharp and excellent image.
Very good condition (except for two small cracks to the main body) for this extremely rare astronomical telescope, kept in its beautiful contemporary case. A Museum piece.
The case measures 21.5 cm in length.