1 / 25

Types of Telescopes

Types of Telescopes. Dr. Charles Ophardt EDU 370. Refractor. Refractor - Light gathered through objective lens on front of telescope Advantages- Rugged Sealed so does not need cleaning Sealed from air currents and temperature effects. Refractor II. Diagram. Refractor III. Disadvantages

bjorn
Download Presentation

Types of Telescopes

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. Types of Telescopes Dr. Charles Ophardt EDU 370

  2. Refractor • Refractor - Light gathered through objective lens on front of telescope • Advantages- • Rugged • Sealed so does not need cleaning • Sealed from air currents and temperature effects.

  3. Refractor II • Diagram

  4. Refractor III • Disadvantages • Chromatic aberration produces a rainbow of colors around image • Reduce with long focal length or multiple compensating lenses • UV does not pass through glass • Less light passes through thicker lens • Difficult to make lens perfect • Large lens sags under own weight

  5. Reflector Telescope • Uses a parabolic mirror to gather and focus parallel light rays

  6. Reflector Telescope II • Advantages • Do not have chromatic aberration • Objective mirror may be very large because back can be supported • Cheaper to make • Only one side of objective must be perfect • Example 200 inch Hale at Palomar Observatory. • 400 inch Keck with 36 hexagonal mirrors

  7. Reflector Telescope III • Disadvantages: • Easy to get optics out of alignment • Open to outside - needs frequent cleaning • Secondary mirror to redirect light can produce diffraction effects • Primary mirror can have a defect if not curved enough. Hubble was too flat by 2 microns.

  8. Powers of a Telescope • Light gathering power • Larger diameter objective lens gathers more light • Resolving Power • Is the ability to see small details • Again larger diameter objective • Can use several telescopes spaced apart and use interferometer to make sharper images

  9. Atmospheric Refraction • Air molecules cause refraction of light • Turbulent motion of air molecules results in a twinkle effect and blurred images • Effect is called “seeing” • Correction is to put telescope as high up on a mountain as possible • Good seeing is when air is stable

  10. Reddening • Air and dust absorbs and scatters electromagnetic radiation • Reddening happens when red light (longer wavelength) is scattered less by molecules and dust. • Reddening seen in the sun at low horizons - other colors scattered out of your line of vision • Blue light (shorter wavelength) scatters more - result is blue sky

  11. Extinction • All wavelengths are scattered or absorbed by some amount. • Absorption of light is called extinction • Infrared absorbed by water and carbon dioxide • UV absorbed by O2, O3, N2 • Gamma / X-rays absorbed by O2 and N2 • Long Radio waves blocked by electrons

  12. Optical / Visible Light • Visible light views of Andromeda and Centaurs galaxies

  13. Electromagnetic Spectrum

  14. Radio Telescope • Uses a large metal parabolic shaped dish or wire mesh • Signals are focused on an antenna • Amplified and computer processed • False colors are used to indicate the intensity of the image

  15. Radio Telescope • Charged particles in magnetic field produce large amts. radio energy

  16. Spitzer Space Telescope - Infrared • Infrared beyond red in the visible spectrum • All objects in space emit some IR or heat radiation - can even see through or detect dust around stars • Infrared radiation is largely absorbed by the atmospheric water vapor and carbon dioxide. • Space based telescope

  17. Spitzer Space Telescope - Infrared • Kepler Supernova • False color views from • X-ray- blue/green • Visible - yellow • IR - red

  18. Ultraviolet Image • A striking ultraviolet image of the spiral galaxy M81 from XMM-Newton's Optical Monitor camera - European X-ray Satellite • This ultraviolet image of M81 was obtained by the Optical Monitor (OM) on XMM-Newton in April 2001. The image is formed from three 1000 s exposures taken with different ultraviolet filters, centred on approximately 2000, 2300 and 2800 angstroms respectively.

  19. Chandra X-ray • NASA's Chandra X-ray Observatory, • Launched and deployed by Space Shuttle Columbia on July 23, 1999. • Most sophisticated X-ray observatory built to date. • Observe X-rays from high-energy regions of the universe, such as the remnants of exploded stars.

  20. Chandra X-ray Images • Crab Nebula and Milky Way

  21. Compton Gamma Ray • The Compton Gamma Ray Observatory (GRO) is a sophisticated satellite observatory • Compton carries four instruments which can detect an unprecedented broad range of high-energy radiation called gamma rays. • Study energetic celestial phenomena: solar flares, gamma-ray bursts, pulsars, nova and supernova explosions, accreting black holes of stellar mass, quasar emission, and interactions of cosmic rays with the interstellar medium.

  22. Compton Gamma Ray Images • Centaura galaxy - left gamma ray image; right visible

  23. Crab nebula • The Crab Nebula's creation was witnessed in July of 1054 A.D. • Chinese astronomers and members of the Native American Anasazi tribe separately recorded the appearance of a new star. • Although it was visible for only a few months, it was bright enough to be seen even during the day! • Star which suffered a supernova explosion. Core of the star collapsed and formed a rapidly rotating, magnetic neutron star.

  24. Crab nebula • Optical, Radio, X-ray, UV

  25. References • http://www.astronomynotes.com/telescop/s1.htm • http://heasarc.gsfc.nasa.gov/docs/xte/learning_center/universe/crabneb.html

More Related