Chapter 21, section 1
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Transcript of Chapter 21, section 1
Chapter 21, section 1
Tools of Modern Astronomy
By Rusty Sturken
Electromagnetic Spectrum
• Electromagnetic radiation is energy that can travel directly through space in the form of waves
• Electromagnetic spectrum is the range of wavelengths of electromagnetic waves
• Visible light is light that you can see with your eyes
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Electromagnetic Spectrum
Image from http://www.lcse.umn.edu/specs/labs/images/spectrum.gif
Visible Spectrum
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Telescopes• A telescope is a device built to study
distant objects by making them appear closer
• A refracting telescope uses convex lenses to gather a large amount of light onto a small area
• A reflecting telescope uses mirrors to gather a large amount of light onto a small area
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Telescopes• A radio telescope uses curved,
reflecting surfaces to concentrate faint radio waves from outer space onto small antennas
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Refracting telescope
Image on left from http://www.dkimages.com/discover/previews/941/25018530.JPG
Image on right from http://www.adlerplanetarium.org/research/collections/instruments/images/g33_72.jpg
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Reflecting Telescope
Image on left from http://astro-canada.ca/_en/_illustrations/a4304_newton_en_p.jpg
Image on right from http://www.stargazer.htmlplanet.com/telescope.jpg 7
Radio Telescope
Image on left from http://pro.corbis.com/images/RF4411534.jpg?size=572&uid=%7BD0356A80-EEEE-4A3C-ACBA-86BB2F75551D%7D
Very Large Array Telescope
Image on right from http://www.aoc.nrao.edu/~emomjian/ao002.jpg
Arecibo Radio Telescope
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Hubble Space Telescope
Image from http://www.sc.gov/NR/rdonlyres/93C9CEAE-361E-4F3B-B4C4-CEDD151A6321/2769/FloatingHubble.jpg 9
Spectrographs• A spectrograph breaks light from an
object into colors and photographs the resulting spectrum. It can tell:– Chemical composition of a star– Temperature of a star
Image from http://www.astrosurf.com/aras/dearden/Telescope&Spectrograph2.jpg
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Spectrographs
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Spectrographs
Image from http://www.scienceinschool.org/repository/images/issue4spectrometer11_large.jpg12