Telescopes

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Antenna

LARGE COLLECTING AREA

Receiver

LOW NOISE

Slide 106

Cryogenics

One way to lower noise is to operate all the electronics at low temperatures.

This lowers the thermal noise resulting in a higher signal to noise S/N ratio.

Slide 107

Cryogenics

The desired cooling to less than 20K is accomplished with high pressure helium gas.

Most telescopes are equipped with helium compressors.

The electronics are operated in a cryostat (thermos) containing high pressure helium gas.

Slide 108

Receiver/cryostat

Helium pump

Cryostat

Slide 109

Cryogenics

Helium manifold

Helium

from compressor

Slide 110

Radio, millimeter, and submillimeter astronomy

The place of radio, millimeter, and submillimeter astronomy the study of astronomy

The parts of a radio telescope and how it works

The two big challenges of radio astronomy overcome by radio astronomers

Tiny signal strength of radio signals

Low angular resolution

Next generation radio, millimeter, and submillimeter telescopes

Slide 111

What is resolution?

High resolution

Low resolution

Andromeda galaxy

Slide 112

What is resolution?

The resolution of a telescope is expressed as an angle.

Slide 113

What is resolution?

10 arc sec

5 arc sec

Greatly magnified views

Slide 114

What is resolution?

The resolution of a telescope is equal to:

wavelength

telescope diameter

Since radio waves have longer wavelengths

than all other forms of EM waves,

the resolution of radio images in inherently

lower.

Slide 115

What is resolution?

The resolution of a telescope is equal to:

wavelength

telescope diameter

One way to increase the resolution is to

increase the diameter of the telescope.

Slide 116

What is resolution?

Arecibo Observatory

300 meters

This is about the biggest diameter that is practical to build