Radio Telescopes

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Radio Telescopes
ROBOTS Professional Development Workshop PARI
School of Galactic Radio Astronomy
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Discovery of Radio Astronomy

• Radio Waves first discovered by Hertz in 1888
• Radio Astronomy born 1931 when Karl Janski first
  detects extra terrestrial radio waves
• Source Galactic Center
• 1937 Grote Reber first modern radio telescope
• 1944 Reber publishes first radio map of sky

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Janskis First Radio Telescope
Image courtesy of NRAO/AUI
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Reception of Radio Waves

• Radio waves cause oscillation of free electons in
  metals.
• A radio dish reflects radio waves and focuses the
  waves to a point
• The intensity of radio waves striking the dish is
  measured as voltage

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Radio Waves arrive at the dish and are focused to
the Receiver. The Receiver converts the radio
waves to an electric signal that is amplified and
recorded.
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PARI
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Formation of 21cm Radio waves(1420 MHz)
One source of radio waves from space is hydrogen
gas. The hydrogen atom can emit a radio wave
with a wavelength of 21 cm or frequency of 1420
MegaHertz.