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TELESCOPES F10

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					TELESCOPES
      What is it?
 A telescope is an optical
instrument used to magnify
  and enhance the view of
      faraway objects.
       What does it do?

• A Telescope COLLECTS light.
• A Telescope FOCUSES light.
• A telescope MAGNIFIES.
 What’s the most important thing?
• SIZE matters – larger scope will collect
  more light and resolve it better.
• YOU GET WHAT YOU PAY FOR – the
  precision of the construction influences
  image clarity as well as durability.
• MAGNIFICATION is the least important
  factor.
   What are the main types?

  There are three main types of
        optical telescopes.
• REFRACTOR
• REFLECTOR
• CATADIOPTRIC
  REFRACTING TELESCOPE
• Simplest and oldest type
• Uses lenses to collect, focus, and magnify
• Considered best for viewing PLANETS
Refracting Telescope
Refracting Telescope
  REFLECTING TELESCOPE
• Uses MIRRORS to COLLECT and
  FOCUS light
• Uses a lens to MAGNIFY the image
• Often referred to as a “NEWTONIAN”
• Invented by……you know who!
Reflecting telescope
Newtonian Telescope
CATADIOPTRIC TELESCOPE
• Modern design, mid 1900’s
• Uses a combination of MIRRORS and
  LENSES to COLLECT, FOCUS and
  MAGNIFY.
• Many variations on this theme
• Most common is the Schmidt-Cassegrain
Schmidt-Cassegrain Light Path
   (Many variations exist!)
Schmidt-Cassegrain
     MOUNTING SYSTEMS
         Two basic types are called
  ALTITUDE-AZIMUTH and EQUATORIAL
• ALT-AZ can be adjusted for SIDE TO
  SIDE and UP AND DOWN.
• ALT-AZ cannot track an object for any
  length of time.
• ALT-AZ is quick and easy to use.
     MOUNTING SYSTEMS
          Two basic types are called
  ALTITUDE-AZIMUTH and EQUATORIAL
• EQUATORIAL must be aligned with the
  POLE to work properly.
• EQUATORIAL can be adjusted for
  DECLINATION and RIGHT ASCENSION.
• EQUATORIAL can easily track an object
  for a long period of time.
          SIZE MATTERS
• Lightweight mounts tend to “jiggle”
• Lightweight mounts don’t hold position
• Heavy mounts hold steady and true
• Locking hardware allows precise alignment
• Heavy and lockable systems are not always
  easy to use, require practice
• Special mounting accessories needed for
  Astrophotography
      There’s an alternative!
• In the 1960’s an amateur Astronomer in
  San Francisco invented a new mounting
• It is named after him – DOBSONIAN
• DOBSONIAN MOUNT can be made large
  and heavy, which has advantages
• DOBSONIAN MOUNT is easy to use and
  operate.
DOBSONIAN MOUNT

				
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posted:6/28/2011
language:English
pages:19