Keplerian telescope with two convex lenses
Telescopio kepleriano de dos lentes convexas
- Date
- 1611 · confidence high
- Place
- Prague, Czechia
- Credited to
- Johannes Kepler (design); Christoph Scheiner (construction)
- Field
- Communication
What it is
In the Dioptrice Kepler describes a telescope with a convex eyepiece, which gives a wider field and allows a reticle for measuring. Scheiner built it around 1613 and it became the standard in astronomy.
Galileo's telescope uses a concave eyepiece; Kepler only described the Keplerian type and Scheiner built it around 1613; Francesco Fontana claimed to have built one in Naples around 1608-1646, without firm proof.
What it led to
- reticle and filar micrometer (Gascoigne) in astronomical telescopes
- long-focal-length refractors of the 17th century
- telescope optics of Huygens and Hevelius