Download Radio Telescope Basics

Radio Telescope Basics
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Three Basic Questions:
What do Radio Telescopes do?
How do Radio Telescopes work?
How are Radio Telescopes similar or dissimilar to Optical Telescopes?
What do Radio
Telescopes Do?
• They “gather” Radio waves just like optical
Telescopes “gather” light!
– Concentrate radio waves that fall on the
telescope “dish”
– Bounce (reflect) waves from the dish to a
radio receiver
– Concentrating the waves gives information
with more definition and resolution
How do Radio Telescopes work?
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Some
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radio
radio
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Once you get the raw signal
from the antenna…
Learn more
A few details:
Receiver and Amplifier
• Receivers use cooled HFET
(Heterostructure Field-Effect Transistors)
• These are very Low-noise input amplifiers.
• HFET Receivers are reliable and stable.
They have an entire octave of bandwidth
without unnecessary noise. What’s more,
they’re cooled to keep the signal to noise
ratio high.
Why are receivers cooled?
• Cooling a receiver:
– Reduces Thermal Noise. The electronics in
the telescope emit radio waves themselves.
Cooled electronics emit much less radiation,
much less “noise”.
– By reducing noise, the weak signal will be
elevated in relative strength
– The coolant used is typically either liquid
Nitrogen or liquid Helium.
LEARN MORE
• Visit this site and research several radio
telescopes. For each telescope, answer the
following questions:
• Where is it?
• What organization runs it?
• What is the telescope’s diameter (in meters)
• What wavelengths / frequencies does the
telescope detect.
• For what investigations is the telescope being
used?
• Name one fun fact about the telescope