Telescopes

A telescope is a device used to concentrate EM radiation, in order to observe a remote object. This concentration increases the apparent and of the object. There are three main types of ground based telescope:

• and

The size of the 'collector' is determined by the of the radiation and the of the signal.

Telescopes can also be placed in around the as . These can provide better results as they do not suffer from absorption (most infra red frequencies do not reach the Earth's surface) and disruption by the . They are also more sensitive to weaker signals because they are colder and in darker surroundings. The big disadvantage is the .