1. Telescopes
Augmenting the Eye

2. Telescopes are devices that allow us to see things far away better.
The word comes from the Greek:
Τελε = Far Σκοπος = Seer Or
Τελεσκοπος “Farseer”
All telescopes gather E-M waves (light) and focus it.
Some even let you ‘see’ wavelengths you can’t normally see.
For example Radio telescopes lets us ‘see’ radio and microwaves.

3. The Parts of an Optical Telescope
An optical telescope gathers visible light to create an image.
All have the following parts:
An “Objective” lens or mirror that gathers light and creates a real image of the object.
Light passes through it or reflects off it first.
An “Eyepiece”, a converging lens that makes a magnified virtual image of the real image made by the objective
It is this virtual image that you see.

4. Two types of Optical Telescopes
Refracting Telescopes or “Refractor” Which gathers light using a Converging Lens as an Objective
Reflecting Telescopes or “Reflector” Which gathers light using a Concave Mirror as an Objective