telescopes. galileo 1609 the moon as a world jupiter has moons
Post on 20-Dec-2015
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Telescopes
Galileo 1609
The Moon as a World
Jupiter has Moons
Refracting telescopes
Isaac Newton’s reflecting telescope
Reflecting telescope
Objective mirrors instead of lenses
Three Powers
• Magnifying
• Resolving
• Light Gathering
Magnifying Power
• Ability to make objects appear larger in angular size
• One can change the magnifying power of a telescope by changing the eyepiece used with it
• Mag Power = focal length of objective divided by the focal length of the eyepiece
Resolving Power
• Ability to see fine detail
• Depends on the diameter of the objective lens or mirror
Light Gathering Power
• The ability to make faint objects look brighter
• Depends on the area of the objective lens or mirror
• Thus a telescope with an objective lens 2 inches in diameter has 4 times the light gathering power of a telescope with a lens 1 inch in diameter
Herschel & Lord Rosse
19th century: epoch of the large refractors
Refracting telescopes
Vienna
Lick
YerkesObservatory
20th century Large Reflectors Come of Age
Mount Wilson
Palomar (5-m)
4 meter Reflectingtelescope
Objective Mirror
Dome of 4 meterKitt Peak
Keck Telescopes
Rooftop telescopes
MSU Campus Observatory
SOAR Telescope
SOAR Telescope -- Cerro Pachon
Astronomical “seeing”
• Blurring effect of looking through air
• Causes stars to twinkle
Bad seeing onthis side
Good seeingon this side
Electromagnetic Spectrum
Radio TelescopesArecibo
Very Large Array
Very Large Array
Observing from space
• No clouds
• Perfect seeing
• Can see wavelengths of light blocked by the earth’s atmosphere
Hubble Space Telescope