Telescopes Chapter 1 Section 2

Telescopes What color are Saturn’s Rings? What does the surface of the moon look like? You could use a device called a telescope. Telescope- is an instrument that gathers electromagnetic radiation from objects in space and concentrates it for better observation

Optical Telescopes Most common of telescopes. The optical telescope collects visible light and focuses it to a focal point for closer observation A Focal Point is- the point where rays of light that pass through a lens meet or that reflect from a mirror and meet.

Refracting Telescopes Refracting Telescopes- uses a set of lenses to gather and focus light Two Disadvantages Images are not always focused because the lenses focus different colors of light at slight different distances, so images appear slightly blurred. The size of a refracting telescope is also limited by the size of their objective lens.

Reflecting Telescope Reflecting Telescope- uses a curved mirror to gather and focus light from distant objects. Advantages Mirrors can be larger; therefore, the larger the mirror the more light being gathered Flaws in the glass does not affect light because curved mirrors are polished. Allow all colors of light from an object to be seen in focus at the same time

Optical Telescopes-gather visible light -loss of brightness -lens expensive -larger the lens, more magnification, but more bubbles Better Hubble Space Telescope

Optical Telescopes and the Atmosphere Why mountains can help. Light gathered by telescopes on Earth are affected by the atmosphere Light pollution can make the sky look bright Astronomers often place telescopes in dry areas to avoid moisture in the air.

Optical Telescopes in Space To avoid interference scientist have put telescopes in space.

Importance of Light Allows us to look back in time Travels at 984,000,000 ft/sec. A Light Year is: The distance light travels in one year Nearest Galaxy is Andromeda 2 million light years away (fastest rocket-30,000 mi/hr)

Summary The bending of light called Refraction. Passing white light through a prism separates or refracts the light into different colors. Reflection occurs when light or any other wave bounces off an object. Reflection enables you to see objects that don't produce their own light. Mirrors

Nonoptical Telescope-gathers invisible light http://www.youtube.com/watch?v=FSEA5_br7J0