Youtor
Kepler telescope
YOUR LINK HERE:
http://youtube.com/watch?v=3vWjvPD_OCU
The Kepler telescope principle combines two focusing lenses, where the focal length of the first lens is identical to the focal length of the second lens. Thereby, a parallel beam (from a distant object like a star) is focused on that point, which is observed via the second lens, similar to a magnifying glass. As a result, the angle of the parallel beam to the optical axis is enlarged (= larger image). This image is, however, upside down. The Galileo telescope (or terrestrial telescope) (see • Galileo telescope ) uses a focusing and a defocusing lens, and the image orientation remains the same.
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