Answer Happy

5. Galileo composed lenses to make his telescope so as to discover mountains on the Moon in 1609. His initial version magnified 8x but was soon refined to the 20x magnification. It had a plano-convex objective lens and a plano-concave eyepiece in a long tube. The main problem with his telescopes was their very narrow field of view, typically about half the width of the Moon. t + fe fo fo Galilean telescope Keplerian telescope Instead, the smaller, concave lens in the eyepiece is chosen to make a Keplerian telescope. This telescope does not focus at the same place (that the Galilean one does) and needs to adjust it differently to get a clear image. Having done so, this telescope inverts the image, but at the same time images a larger one - it does not magnify more but it gives a larger field of view. (You may be able to fit the entire moon into your field of view.) Question: How does the improvement of Kepler's refracting telescope provide better performance than the Galilean one?