TELESCOPES

From The Way Things Work

By David Macaulay

Telescopes

• A telescope gives a close up view of a distant object

• Most telescopes work the same basic way• A real image of an object is magnified

inside of a telescope tube• The degree of magnification depends on

the eyepiece lens• There are many kinds of telescopes:• Refracting, Reflecting, Radio, Space

Refracting Telescopes

• In a refracting telescope, an objective lense forms the real image that is viewed by the eyepiece lens. The image is upside down

• Astronomy

Reflecting Telescope

• The larger concave primary mirror forms the real image that is then viewed by the eyepiece lens.

• A second mirror reflects the rays form the primary mirror so that the real image is formed right-side up

• Used in astronomy- wide mirrors can catch more light from far away

Radio Telescope• A large curved

metal dish used to collect sound waves

• Reflects them to the center of the dish to an antenna

• The weak electric signal then goes to a computer

Space Telescope• Hubble space

telescope is part eye and part radio telescope

• It will revolutionize astronomy

• It orbits the earth, and sees 7 times farther into the universe than at ground level

• May also see back into time by seeing old light waves from distant galaxies

VOCABULARY

• ANCESTORS- People from whom one is descended

• SUMMONING-asking to come

• ATTENDANTS- people who wait on someone

• HEAVENS - the sky as viewed from Earth

• VAIN- conceited

Spelling

• Brief• Grieve• Nasty• Receive• Memory• Scary• Gasoline• Piece• Ceiling• Ski

• Chief • Belief• Monkey• Field• Every• Shield• Journey• Seized• Spirit• safety