Download Telescopes

Telescopes
Optical Telescopes
Images can be formed through reflection
(mirror) or refraction (lens).
Reflecting mirror
Optical Telescopes
Refracting lens
Optical Telescopes
Reflecting and refracting telescopes
Optical Telescopes
Modern telescopes are all reflectors (use a
mirror):
• Light traveling through lens is refracted
differently depending on wavelength.
• Some light traveling through lens is
absorbed.
Optical Telescopes
Image acquisition: Chargecoupled devices (CCDs) are
electronic devices, can be
quickly read out and reset.
Radio Astronomy
Interferometry:
• Combines information
from several widely
spread radio telescopes
as if it came from a
single dish.
Other Astronomies
Infrared radiation can image where visible
radiation is blocked; generally can use optical
telescope mirrors and lenses.
Other Astronomies
Much can be learned from
observing the same
astronomical object at many
wavelengths. Here, the Milky
Way.
Electromagnetic Spectrum
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All the types of radiation are shown on
the electromagnetic spectrum from long
wavelengths (radio) to short wavelengths
(gamma).
We can only use our eyes to see a very
small portion of the radiation that is
emitted in the universe (visible light)
Electromagnetic Spectrum