Telescopes

What is a telescope?

A tool used to focus far away light so it can be studied (Galileo Galilei)

Ray

a beam of light that appears as a straight line -Still acts as a wave but does not appear as one on large scale

Reflection telescopes

bending light rays by bouncing them off of a surface, and passing light rays through a lens. -uses lenses to focus light rays

Reflecting telescopes

use mirrors to focus light rays -more popular -larger lenses

primary mirror (reflector)

at the base of the telescope

secondary mirror (reflector)

location and orientation varies

larger the telescope

the more light it can collect, the better/smaller its resolution

A=πr²

If the main mirror of a telescope is a circle then its area is given by

amount of light ∝ radius²

Bigger telescopes collect more light

resolution ∝1/diameter

Bigger telescopes have better/smaller resolution

The atmosphere only lets certain wavelengths pass through to the surface

-little ultraviolet & infrared light gets through -no X-rays or gamma rays (we can only detect them directly in space)

Hubble Space Telescope (HST) (NGC 4603)

-Main mirror is 2.4m in diameter -Can observe visible, infrared, and ultraviolet radiation

The James Webb Space Telescope (JWST)

-Main mirror is 6.5m in diameter -Designed for infrared observations —Studies the formation of stars and galaxies, planets around other stars