Galilean telescope: similar to E+30+45.

Galilean telescope: Using objective and eyepiece lenses (much like X). The Galilean telescope is used to view objects that are far away. This simple telescope consists of an Eyepiece which is a diverging lens with a short focal length (fe = -5"), and an Objective which is a converging lens with a longer focal length (fo = +28"). The lenses are mounted on an optical bench to insure alignment. The object to be viewed is an Arrow Object Card mounted on a distant wall, 25 feet or so away. The Objective (the lens nearest the viewed object) forms a real inverted image at fo, which is a focal length fe past the Eyepiece. This image is the virtual image for the negative focal length Eyepiece. Thus, the image viewed in the Eyepiece is right side up. The distance between the lenses to have the arrow in focus for viewing is the sum of the focal lengths (fo+fe = -5"+28" = 23"). Placing an eye (or a TV camera) close to the eyepiece will see the distant arrow magnified by the ratio of the focal lengths (fo/fe = 28"/5" _6). That is, the arrow is 6 times larger than what would be seen by the unaided naked eye.