Telescopes

4 main types of telescopes

Refractor (uses lenses)

Newton Reflector (uses mirrors)

Maksutov-Cassegrain (uses a spherical creation lens)

Schmidt cassegrain (uses a complex correction lens)

Spherical mirrors are cheap to make but they don't focus

2 main mounts: Alt-AZ and Equatorial mount

The Great Equatorial 28" refractor

Refractor means 2 lenses

At the Royal Observatory Greenwich and was built in 1893

7th largest refractor in the world

Large telescopes

The large binocular telescopes in Arizona

The Very large telescope in Chili

The VLT uses interferometry - 4 telescopes working together

Adaptive Optics

Used to combat blaring and distortions caused by the moving atmosphere

Flexible mirrors cancel out atmospheric distortions

Use laser guide stars to look at way laser is bent to know which way to bend the mirrors

European Extremely Large Telescope: being built in Chili, is 39 metres