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Telescopes. TELESCOPES ALLOW US TO STUDY SPACE FROM EARTH!!!. History. Galileo Galilei (1564-1642) 1 st telescope invented in Holland in 1609 Galileo learned of this and made his own: small 30X scope
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Telescopes TELESCOPES ALLOW US TO STUDY SPACE FROM EARTH!!!
History • Galileo Galilei (1564-1642) • 1st telescope invented in Holland in 1609 • Galileo learned of this and made his own: small 30X scope • Observed the moon and “began” the modern age of Astronomy where measurement was more important than philosophy
Galileo noticed • moons orbiting Jupiter • phases of Venus • craters on the moon • sunspots This was strong evidence that Copernicus was right although Galileo wasn’t willing to die for it. The sun was the center of the solar system!
Lenses • The lens in your eyes works like a glass lens. The light bends as it goes through a different medium. • Light rays are bent when they intersect glass; a curved surface can produce an image. • In your eye, the image is then focused at the retina.
How does this apply to telescopes? • If you had a bigger eye, you could collect more light from the object. This image could be magnified so it stretches out over more pixels in your retina. • In a telescope, two pieces make this possible: • the objective lens (refractor telescopes) or primary mirror (reflecting telescopes) • the eye piece
Not everything is visible… • Many modern day telescopes do not use visible light to collect images. • Radio telescopes, x-ray telescopes and infrared (IR) telescopes have become a staple of modern day astronomy, producing some amazing images. www.yorku.ca/eye/spectrum.gif
How a telescope works • TELESCOPE: a device that gathers electromagnetic radiation • VISIBLE LIGHT TELELSCOPES
Famous Optical Telescopes on Earth • Keck Telescope-Mauna Kea HawaiiMirror is 10 meters wide • Kitt Peak ObservatoryTuscon, AZhttp://www.noao.edu/outreach/kptour/
Very Large Array (VLA)radio telescopes in New Mexico, signals are combined to produce clearer images RADIO TELESCOPES Show where radio waves are being emitted by objects in space Has a dish & antenna ; Need to very BIG because radio waves are so long Very little interference
Problems with earth-based telescopes • Earth’s atmosphere reflects certain wavelengths • x-rays, gamma rays and most UV light is not transmitted by our atmosphere • Earth’s atmosphere blurs images • the bending of light by the atmosphere depends on the temperature of the “air” • “twinkling” (shimmering) effect • “Light pollution” • Solution? Put the telescope in space. HUBBLE
Telescopes in SPACE • Hubble Space Telescope-reflecting telescope • Placed in orbit in 1990 • Collects visible light, infared, & ultraviolet • Chandra X-ray Observatory 1999 • Compton Gamma-Ray Observatory 1991 • Spitzer (infared) 2003
Disadvantages of space-based telescopes • Expensive to launch and maintain • Difficult to repair • Low lifetime Spitzer http://www.jwst.nasa.gov/Jame Webb Telescope 2014