AST101H5 Chapter Notes - Chapter 5: X-Ray, Adaptive Optics, Hubble Space Telescope
Document Summary
Telescopes enables astronomers to observe things not visible to the naked eye. Telescopes gather much more light than your eye, allowing more stars to become visible. For your eyes to see an object, photons from it must strike the retina in large enough numbers to stimulate chemical reactions in nerve cells. How bright an object is depends on the number of its photons that enter our eye per second, a number limited to the size of our pupils. Telescopes allow us to collect photons by funneling them into our eyes. The bigger the telescope, the more photons it collects. More photons means brighter image, so a larger telescope may be able to see stars that a smaller telescope could not detect. Once light has been gathered, it must be focused to form an image or to concentrate it on a detector. A telescope in which light is gathered and focused by a lens.
