A selection of early draw tube refracting telescopes, early 18th century.
© Science Museum / Science & Society Picture Library
Pietro Patron in Milan, Italy made the smallest telescope with its ivory mounted lenses and decorated green vellum tube. The larger telescope with green parchment tube on a wooden stand is unsigned but also Italian in origin. The largest telescope made from wood and leather is by an unknown English maker, and when fully extended measures 16 1/2 feet. Unlike Galileo's (1564-1642) telescopes, they are fitted with convex eyepiece lenses, as first suggested by the astronomer Johannes Kepler (1571-1630) in 1611. This gives them a much wider field of view than Galileo's telescopes, while the inverted image can be made upright by adding an extra convex lens.