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

-loss of brightness

-lens expensive

-larger the lens, more magnification, but more bubbles

Optical Telescopes-gather visible light

Better

Hubble Space Telescope

Optical Telescopes and the AtmosphereWhy 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 Andromeda2 million light years away (fastest rocket-30,000 mi/hr)

Summary

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

The bending of light called Refraction. Passing white light

through a prism separates or refracts the light into different colors.

Nonoptical Telescope-gathers invisible light

http://www.youtube.com/watch?v=FSEA5_br7J0