Telescopes  Device used to collect Light and to Magnify Distant Objects  Plans made by Rodger Bacon 13 th Century  Galileo improved the Device

Bacon and Galileo

Some History  Galileo was first to use the telescope to view the night time sky  Devised a method to smooth and polish the lenses Made image clearer (focus) Made image clearer (focus) First telescope 8x the Magnification First telescope 8x the Magnification During his Studies increased to 32x the Magnification During his Studies increased to 32x the Magnification

Types of Telescopes  Optical Gathers and Focuses Visible Light Gathers and Focuses Visible Light  Radio Directional Radio Antennae Directional Radio Antennae  Gamma and X Ray Heavy Metal Reflectors Heavy Metal Reflectors

Optical Telescopes  Three Types of Optical Telescopes Refracting Refracting Reflecting Reflecting Uses Mirrors to Produce ImageUses Mirrors to Produce Image 1668, Most Common1668, Most Common Catadioptric Catadioptric Uses a Combination of Mirrors and LensesUses a Combination of Mirrors and Lenses

Refracting Telescopes Uses Lenses to Produce Image Uses Lenses to Produce Image Galileo 1600’s Galileo 1600’s Improved magnification 30x Improved magnification 30x Uses lenses to refract light (bend) Uses lenses to refract light (bend) Yerkes in Lake Geneva (One of the Largest) Yerkes in Lake Geneva (One of the Largest)

Refracting Telescope Flaws  Chromatic Aberration Shorter wavelengths are bent more than longer ones Shorter wavelengths are bent more than longer ones Weakens image and produces a halo of color Weakens image and produces a halo of color When focusing on a red object, blue and violet halo appears When focusing on a red object, blue and violet halo appears When focusing on a blue object, red and orange halo appears When focusing on a blue object, red and orange halo appears

Yerkes Observatory

Reflecting telescopes Reflecting Telescopes  Newton Used concave mirrors that focuses the light in front of the mirror rather than behind Used concave mirrors that focuses the light in front of the mirror rather than behind Mirror is finely grained and coated with aluminum Mirror is finely grained and coated with aluminum

Reflecting Telescope Advantages  Light doesn’t pass through mirrors so glass doesn’t have to be of optical quality  Mirrors can be supported fully from behind, whereas lenses can only be on the sides which makes lens sag

Magnification Magnification Focal Length of Object Focal Length of Eye Piece

Radio Telescopes  Collects Radio Waves with Huge Dishes  Focuses incoming radio waves on an antenna, which absorbs and transmits these waves to an amplifer  Interferometry: Linking separate telescopes together to form one great one Helps to pinpoint source of the radio wave radiation Helps to pinpoint source of the radio wave radiation

Advantages  Not affected by turbulence in the atmosphere, clouds, and the weather  No Dome  24 hours a day viewing  Can see through interstellar dust which optical telescopes cannot

Types of Telescopes

Satellites and Probes  To get better pictures of Space, You need to Leave Earth’s Atmosphere  The Atmosphere Distorts Incoming Radiation  Hubble – 1990  Probes – Mars Odyssey 2001  Chandra X-ray Observatory 1999 (Black Holes)  International Space Station  James Webb Space Telescope 2011  Compton Gamma – Ray Telescope

Mars Odyssey and ISS