Telescopes

Section 1-4

TelescopeTele – distant, farScope- see Invented in the 16th centuryFirst used by Galileo Who found moons

around JupiterOptical telescopes collect lightTwo types

– Refracting– Reflecting

Refracting TelescopesUse lenses to bend lightLarger lenses can gather more lightSo get better pictureLargest is 40 inches acrossLarger are not possible because the

lenses distort the light.

Yerkes Observatory

Reflecting TelescopesUse mirrors to collect lightFirst made by NewtonMirrors can be largerLargest is 200 in. at Mount

Palomar near San Diego

Put telescopes in domes with doors that slide open

Allow them to rotate and elevatePoint at the same point in the sky as the

earth turns.

Multiple Mirror Telescopes

Large mirrors are hard to make.Use several small mirrors that act

togetherGather more light

than a single mirror

Keck Observatory36 mirror hexagon segments- computer

controlledLargest optical

telescope

The whole spectrumLight is a small part of the

electromagnetic spectrumThere are telescopes that detect other

types of waves.Radio telescopes- detect radio wavesMany stars give off mainly radio wavesUse computers to create an image from

the waves.Can use several together for even better

images

Radio Telescopes

Arecibo

Infrared telecopes Infrared is heat energy (warming lamps)Don’t travel through atmospherePut telescope on a satellite IRAS Infrared Astronomy Satellite (1983) ISO Infrared Space Observatory (1995)Give us images of things

that give off little energy,like new stars and nebula

Ultraviolet telescopesAlso need to be on satellitesUsed to view our sunAlso found on the Hubble Space

Telescope

X-ray telescopesAlso need to be on telescopesGive information on life cycles of stars.Uhuru 1970Chandra currently in service

Hubble Space TelescopeCombination of telescopes – optical and

ultravioletHas been repaired and upgraded twiceGiving scientists views of the universe

they have never had before