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Radio Telescopes
ROBOTS
Professional Development Workshop
PARI School of Galactic Radio
Astronomy
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
Janski’s First “Radio Telescope”
Image courtesy of NRAO/AUI
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
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.
PARI
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.