Telescopes

TelescopesKey Concepts What are the regions of the

electromagnetic spectrum? What are telescopes and how do they

work? Where are most large telescopes

located?

Telescopes - Key Terms Telescope Electromagnetic

radiation Visible light Wavelength Spectrum Optical

telescope

Refracting telescope

Convex lens Reflecting

telescope Radio telescope Observatory

Telescope A device that makes distant objects

appear to be closer. Galileo made the telescope famous.

He was the first to see sunspots, Saturn’s Rings, and the four large moons of Jupiter

Electromagnetic Radiation Energy that can travel through space in

the form of wavesExamples of Forms of Radiation

visible light – radiation you can see infrared – feel as heat radio waves

Ranges from long wavelength radio waves to short wavelength gamma rays

Types of Telescopes Instruments that collect and focus

light and other forms of electromagnetic radiation.

Optical telescope – uses lenses or mirrors to collect and focus visible lightTwo types – refracting and reflecting

Non-optical – Use other forms of electromagnetic radiation such as radio waves, x-rays and gamma rays

Refracting Telescopes Uses convex lenses to gather and focus light Convex lens is a curved piece of glass that is

thicker in the middle than the edges The larger the lens the more light the

telescope can collect Simple refracting telescope has 2

lenses – the objective lens and the eyepiece lens

Yerkes Telescope in Wisconsin is the largest refracting telescope

Reflecting Telescopes Isaac Newton built the first in 1668 Uses a curved mirror to collect and focus

light The larger the mirror, the more light that

can be collected Largest optical telescopes today are

reflecting

Radio Telescopes Devices used to detect radio

waves from objects in space Most have curved reflecting surfaces that

focus radio waves the way the mirror does in reflecting telescopes

Concentrate the faint radio signals onto small antennas like those on radios

Ex. The Very large Array, Arecibo

Other TelescopesDetect: Infrared – Spitzer Space Telescope Ultraviolet X-rays – Chandra X-Ray Observatory Gamma raysHubble Space Telescope detects visible, ultraviolet, and infrared

Observatories A building that contains one or more

telescopes. (some in space) Many large observatories located on

mountaintops or in space – atmosphere makes images blurry.

Radio telescopes are not affected by atmosphere