How Telescopes Work

Allison Hutton

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

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.

Two Types of Telescopes

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

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

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

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

Refracting vs. Reflecting Telescopes

Refracting Telescope Reflecting Telescope

Disadvantage: telescopes must be large in size in order for the viewer to see the image at the focal point

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

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

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

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