1 / 24

Chapter 5

Chapter 5. How do we learn about objects too far away for spacecraft? How do telescopes work? Do all telescopes use light? Why are telescopes located on mountains? Why are some telescopes in orbit around the Earth?. Astronomical Instruments. 5.1 Telescopes.

Download Presentation

Chapter 5

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chapter 5 How do we learn about objects too far away for spacecraft? How do telescopes work? Do all telescopes use light? Why are telescopes located on mountains? Why are some telescopes in orbit around the Earth? Astronomical Instruments Astronomy 2010

  2. 5.1 Telescopes • Telescopes are devices for “seeing” distant objects. • To see faint objects, collect more light by using a bigger aperture. • Magnification is much, much less important. • Two types of optical telescopes: • Refracting • Reflecting Astronomy 2010

  3. Refracting Telescopes • Use a large lens as the primary light collecting element. • Common in older telescopes. • Chromatic aberrations and ultraviolet cutoff. Astronomy 2010

  4. Astronomy 2010

  5. Reflecting Telescopes • Use a large mirror as the primary light collecting element. • Easier to make a large mirror than a large lens. • Modern telescopes are reflectors. • Reduced chromaticity problems. Astronomy 2010

  6. Refracting versus Reflecting Astronomy 2010

  7. Prime, Newton, and Cassegrain Astronomy 2010

  8. 5.2 Optical Detectors and Instruments • Second greatest advance in astronomy was the use of photographic film • Longer integration time than the eye. • Images available for later (re)inspection. • The 3 uses of telescopes: • Imaging • Measuring brightness and color • Spectroscopy • All benefit from longer integration time. Astronomy 2010

  9. Charge-Coupled Device • A modern advance is the use of charge-coupled devices or CCD’s. • These are the “digital film” of digital cameras. Astronomy 2010

  10. 5.3 Optical and Infrared Observatories • Ground based telescopes are housed in domes or other structures to protect them when not in use. • They are often located on remote mountains, away from lights, and smog, and above humid and turbulent air. Astronomy 2010

  11. NOAO on Kitt Peak, AZ Astronomy 2010

  12. South African Large Telescope Astronomy 2010

  13. European Southern Observatory Astronomy 2010

  14. Choice of Telescope Sites • Weather: clouds, wind, and rain limit observing time. • Water vapor: water vapor in the atmosphere filters out infrared wavelengths. • Darkness: city light can overwhelm faint stars. • Turbulence: turbulent air blurs images. Astronomy 2010

  15. Observatory Sites • Newest telescopes are sited in the Chilean Andes, desert peaks of Arizona, Canary Islands, and Mauna Kea in Hawaii. • Modern telescopes can use segmented mirrors, adaptive optics, and interferometry. Astronomy 2010

  16. Observing Other Radiation • To learn the most about planets, stars, and galaxies, astronomers use as many types of radiations as possible. • Radio • Infrared and ultraviolet • X-rays • Gamma rays Astronomy 2010

  17. 5.4 Radio Telescopes • Many objects emit radio waves, from long wave to microwaves. • Radio telescopes generally look like large satellite dishes. • They can operate during the day and night. • Large facilities in Puerto Rico, West Virginia, and New Mexico. Astronomy 2010

  18. Astronomy 2010

  19. The Very Large Array (VLA) Astronomy 2010

  20. The VLBA Spans A Continent Astronomy 2010

  21. Radio Image of Quasar Jets Astronomy 2010

  22. 5.5 Observatories Outside the Earth’s Atmosphere • Some wavelengths of radiation are absorbed by Earth’s atmosphere (gamma rays, x-rays, and ultraviolet). • Telescopes for these wavelengths must be put in space. • The Hubble telescope demonstrates the advantages for an optical telescope to be above the atmosphere. Astronomy 2010

  23. The Hubble Space Telescope Astronomy 2010

  24. The Swift Satellite (GRB’s) Astronomy 2010

More Related