1. Telescopes
Section 15.1

2. Standard

3. Introduction
Invention of the telescope in 1608 Telescope: an object that makes distant objects appear to be closer Since then, we have built bigger and more powerful telescopes

4. Electromagnetic Radiation
Electromagnetic radiation: energy that can travel through space in the form of waves Forms of Radiation - Visible light: all the colors that you can see, one type of radiation - Radio waves - Microwaves - Ultraviolet Radiation

5. Electromagnetic Radiation
The Electromagnetic Spectrum - wavelength: the distance between the crest of one wave and the crest of the next wave - spectrum: range of different colors, with different wavelengths - The electromagnetic spectrum includes the entire range of radio waves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays.

6. Electromagnetic spectrum

7. Types of Telescopes
Telescopes are instruments that collect and focus light and other forms of electromagnetic radiation. Optical Telescope: Telescope that uses lenses or mirror to collect and focus visible light. Two types: refracting telescope and reflecting telescope

8. Types of Telescopes
Refracting Telescopes - uses a convex lens to gather and focus light. - convex lens: a piece of transparent glass, curved so that the middle is thicker than the edges.

9. Types of Telescopes
Reflecting Telescope - uses a curved mirror to collect and focus light - the largest telescopes today are reflecting Radio Telescope - devices used to detect radio waves from objects in space

10. Observatories
Observatory: a building that contains one or more telescopes - Many large observatories are located on mountaintops in space. - The sky on mountaintops is clearer and not brightened much by city lights Advanced Telescopes - new telescopes now have computer systems that correct images - technology that can automatically adjust parts of the telescope

11. Observatories
Telescopes in Space The atmosphere blocks out a lot of radiation EX: The Hubble Space Telescope - because it orbits Earth above the atmosphere, it can produced very detailed images