Download Telescopes

Telescopes
 1608, Lippershey earliest known working telescope &
first to apply for patent
 Refracting telescope- bends light through a lense and
into the eyepiece. Worked but had some issues:
 Limited size of lens
 Flipped image
 Chromatic aberration- when lens fails to focus all of the
colors of the visible light spectrum at the same time.
Galileo
 1st built by Galileo 1609
 Galileo DID NOT invent the telescope
 Heard of Lippershey design idea 1608
 Refined the design 3x - 30x magnification
 Discovered
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4 largest moons of Jupiter
Craters & Mountains on the moon (topographical maps)
Rings around Saturn
The phases of Venus (similar to the moon’s-proving
heliocentric model)
The planet Neptune
That the Milky Way was tightly packed stars not just nebula.
Isaac Newton
 Built 1st reflector telescope in 1668 using mirrors instead of
lenses to redirect the light into the observers eye.
 All major optical (light we can see) research telescopes are
now reflecting telescopes
 Advantages over refracting telescope
 Only one side of mirror has to be polished/flawless
 Mirror can be bigger than lenses because they can be
supported from behind
 No chromatic aberration.
Refracting & Reflecting Telescopes
Refracting- light
bends or refracts when
going through a lens
Reflecting- light is
reflected off main
curved mirror angling
it to a secondary mirror
that redirects light to
the eyepiece.
Hubble Space Telescope
 Hubble Space Telescope
 Launched 1990 @ cost of $1.5 billion
 Reflecting telescope
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7.9 foot mirror
First pictures were fuzzy
 1993, mirror replaced due to manufacturing defect
1/50th the thickness of a piece of paper.
Hubble
 Allowed us to see into deep space
 Hubble Deep Field
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Patch of “empty” sky
10 days
3,000 galaxies
 NASA plans to
Replace Hubble with
James Webb Telescope
2018.
Kepler Space Telescope
 Kepler was launched March 2009
 Mission is to hunt for terrestrial (rocky) planets in or
near the habitable zone from their star
 Habitable zone-Distance where we believe liquid water
could be present
 Found 1,700+ exoplanets (planets outside our solar
system) since launch.
Other types of telescopes
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Radio Telescopes- observe radio and microwaves
Infrared Telescopes- observe infrared light
Ultraviolet Telescopes- observe ultra-violet light
X-ray Telescopes- observe x-rays
Gamma Ray Telescopes- observe gamma rays
Certain sections of the electro-magnetic spectrum are
visible from Earth, while others are only (mostly)
observable from space. This is due to our atmosphere
and its ability to block portions of the EM spectrum.
Great for our survival, but bad for astronomy on Earth.
Parts of a telescope
 Objective- first lens or mirror that light passes
through or reflects off of
 Eye-piece- lens or mirror light passes through or
reflects off of before entering the eye
 Optical Tube- is the chamber light passes through
between lenses/mirrors
 Secondary Mirror-second mirror light reflects off of
before being sent to eye-piece in some reflecting
telescopes.