1. Light and Optical Systems

2. Objective  Students will recognize telescopes as an optical device, and understand the development of the modern telescope.

3. Getting Started  What do you think the word “optical” means?  How would you compare human eyesight to eyesight in the animal world?  What was beginning of optical systems?  Name an optical system.

4. Magnifying Glass

5. Glasses

6. Telescope

7.  Benefits Simple  Downsides Chromatic aberration Hard to make big lenses Glass is heavy

8. Yerkes Observatory

9. Discussion Questions  Can you think of any possible problems with this kind of telescope?

10. Chromatic Aberration

13. Essential Concept  Big glass lenses Heavy Expensive

14. Simple Solution

15. An Elegant Solution

16. Keck Observatory

18. Review  What does it mean when light refracts?  What does it mean when light reflects?  What are the limitations of refracting telescopes?  What are the benefits of the reflecting telescope?