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Telescopes

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Refracting-uses lens instead of a mirror to focus incoming light. Refraction telescopes. The objective in a refracting telescope refracts or bends light. ... – PowerPoint PPT presentation

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Title: Telescopes


1
Telescopes
  • Chapter 5
  • April 16,2010

2
Telescope Design
  • There are two types of optical telescopes
  • Reflecting-uses a curved mirror to gather and
    concentrate a beam of light
  • Refracting-uses lens instead of a mirror to focus
    incoming light

3
Refraction telescopes
  • The objective in a refracting telescope refracts
    or bends light.This refraction causes parallel
    light rays to converge at a focal point while
    those which were not parallel converge upon a
    focal plane.

4
Refraction Telescopes
5
Types of Reflection Telescopes
  • Newtonian
  • Cassegrain

6
Newtonian Telescopes
  • Newtonian telescope-light is intercepted before
    it reaches the prime focus, and then deflected by
    90 degrees
  • Smaller design, preferred by amateur astronomers

7
Cassegrain Telescopes
  • The Cassegrain reflector is a combination of a
    primary concave mirror and a secondary convex
    mirror

8
Reflection Telescope
9
Hubble Telescope
  • Hubble works on the same principle as the first
    reflecting telescope built in the 1600s by Isaac
    Newton.

10
Hubble Telescope
  • Light enters the telescope and strikes a concave
    primary mirror, which acts like a lens to focus
    the light. The bigger the mirror, the better the
    image.

11
Hubble Telescope
  • In Hubble, light from the primary mirror is
    reflected to a smaller secondary mirror in front
    of the primary mirror, then back through a hole
    in the primary to instruments clustered behind
    the focal plane (where the image is in focus).

12
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13
Mirror Size on Hubble Telescope
  • Primary mirror-2.4 meters (94.5 inches) in
    diameterSecondary mirror-0.3 meters (12 inches)
    in diameter

14
Angular resolution
  • Hubble's angular resolution is 0.05 arcsecond.
    This is the "sharpness" of Hubble's vision. If
    you could see as well as Hubble, you could stand
    in New York City and distinguish two fireflies, 1
    m (3.3 feet) apart, in San Francisco

15
Facts about Hubble Telescope
  • Hubble weighs 24,500 pounds -- as much as two
    full-grown elephants.
  • During its lifetime Hubble has made about 800,000
    observations and snapped about 500,000 images of
    more than 25,000 celestial objects

16
Chandra X-Ray Observatory
  • Launched on July 23, 1999
  • This is an X-Ray Telescope
  • Designed to observe X-rays from high-energy
    regions of the universe, such as the remnants of
    exploded stars

17
Comparison of Crab Nebula
18
Tracking Chandra
  • The Space Shuttle Columbia delivered Chandra to a
    low Earth orbit. Then, the Inertial Upper Stage
    rocket boosted Chandra up to a higher altitude
    where a built-in propulsion system took Chandra
    to its final orbit. This elliptical orbit takes
    the spacecraft to an altitude of 133,000 km -
    more than a third of the distance to the moon -
    before returning to its closest approach to the
    Earth of 16,000 kilometers

19
Chandras Orbit
  • It takes approximately 64 hours and 18 minutes to
    complete an orbit.

20
Vision, Hope, and Triumph Hubble Telescope
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