How Telescopes Work

1. How Telescopes Work • Allison Hutton

2. History • foundation for invention of the telescope was developed between 1350 and 1450 • in 1570 the first actually instrument composed of lenses and mirrors was constructed by Leonardo and Thomas Digges • the telescope was officially released to the public in the Netherlands in 1608 • Galileo was first to take advantage of the telescope to make discoveries in space such as sunspots, Jupiter’s moons, and the phases of Venus

3. Major Uses • mainly used to study astronomy • use ranges from actively attempting to make new discoveries to recreationally star gazing • can view moon, planets, stars, comets, meteor showers, galaxies, nebulae, etc.

4. Two Types of Telescopes

5. Refracting Telescopes • lens used in refracting telescopes was designed by Hans Lippershey in the Netherlands in 1608 • Lippershey created the first telescope by putting his lenses in front of each other in a tube • Galileo used a refracting telescope in during his space study in 1609

6. How Refracting Telescopes Work • convex lens bends light inward • convex lens is thick toward the center of the class in order to bend the light more around the circumference of the lens • the light is focused and an image is created at the focal point • a concave lens is placed near the eyepiece of the telescope in order to magnify the image, thus making it appear closer to the viewer

7. Reflecting Telescopes • James Gregory developed the theory and design in Scotland in 1663 • Isaac Newton put this plan into action and created the first model in 1688

8. How Refracting Telescopes Work • use concave mirrors instead of convex lenses • center of mirror is thinner than the edges • light hits the mirror and reflects back and collects light to form an image at the focal point

9. Refracting vs. Reflecting Telescopes Reflecting Telescope Refracting Telescope Advantages: able to see dark or dim objects, powerful, capable of viewing far distances, clearer images Advantages: lenses are more durable than mirrors Disadvantages: produces unclear images sometimes, size of lens affects power so usually are less powerful Disadvantage: telescopes must be large in size in order for the viewer to see the image at the focal point

10. Relation to Physics 001 • related to three major topics: reflection, refraction, and optics • chapter 28 in Conceptual Physics • from 4/9/12 - 4/13/12 we discussed how light behaves when shone through lenses or on mirrors which is directly related to telescopes • the ray diagrams taught in class come in handy to accurately illustrate the physics behind the telescope

11. Insight • I have used a telescope many times, but never stopped to think how it actually works, and this project allowed me to learn all about the physics behind the telescope • knew that there were reflecting and refracting telescopes, but now I actually understand the difference • learned that there are combination telescopes that involve both lenses and mirrors and these are usually the most effective but require the most effort and are typically constructed for a specific purpose

12. Bibliography • http://galileo.rice.edu/sci/instruments/telescope.html • http://library.thinkquest.org/J0112188/refracting_and_reflecting_telescopes.htm • http://abyss.uoregon.edu/~js/glossary/reflecting_telescope.html