1. Telescopes October 31

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 1600’s 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).

13. Mirror Size on Hubble Telescope Primary mirror-2.4 meters (94.5 inches) in diameter Secondary 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. Chandra’s Orbit It takes approximately 64 hours and 18 minutes to complete an orbit.

20. Vision, Hope, and Triumph: Hubble Telescope http://www.nasa.gov/multimedia/nasatv/on_ demand_video.html?param=http://anon.nasa -global.edgesuite.net/anon.nasa- global/ccvideos/GSFC_20081009_VisHopeTri.a sx&_id=168629&_title=Vision%2C%20Hope% 2C%20Triumph%3A%20The%20Hubble%20Sp ace%20Telescope&_tnimage=281 http://www.nasa.gov/multimedia/nasatv/on_ demand_video.html?param=http://anon.nasa -global.edgesuite.net/anon.nasa- global/ccvideos/GSFC_20081009_VisHopeTri.a sx&_id=168629&_title=Vision%2C%20Hope% 2C%20Triumph%3A%20The%20Hubble%20Sp ace%20Telescope&_tnimage=281