02+REFLECTING+REFRACTING+TELESCOPES



hubble telescope animation:[] 1.5 Explain how to measure the focal length of a converging lens using a distant object. 1.6 Investigate the behaviour of converging lenses, including real and virtual images. 1.7 Investigate the use of converging lenses to: a) measure the focal length using a distant. b) Investigate factors which affect the magnification of a converging lens. 1.8 Explain how the eyepiece of a simple telescope magnifiies the image of a distant object produced by the objective lens. 1.9 Describe how a reflecting telescope works. 1.10 Recall that waves are reflected and refracted at boundaries between different materials. 1.11 Explain how waves will be reflected at a boundary in terms of the change of speed and direction.



**1.8 Explain how the eyepiece of a simple telescope magnifiies the image of a distant object produced by the objective lens.** **If you had a "bigger eye," you could collect more light from the object and create a brighter image, and then you could magnify part of that image so it stretches out over more pixels on your retina. Two pieces in a telescope make this possible:** **When you combine the objective lens or primary mirror with the eyepiece, you have a telescope. Again, the basic idea is to collect lots of light to form a bright image inside th­e telescope, and then use something like a magnifying glass to magnify (enlarge) that bright image so that it takes up a lot of space on your retina.**
 * **The objective lens (in refractors) or primary mirror (in reflectors) collects lots of light from a distant object and brings that light, or image, to a point or focus.**
 * **An eyepiece lens takes the bright light from the focus of the objective lens or primary mirror and "spreads it out" (magnifies it) to take up a large portion of the retina. This is the same principle that a magnifying glass (lens) uses; it takes a small image on the paper and spreads it out over the retina of your eye so that it looks big.**