Telescope+Types

=Refracting Telescope vs. Reflecting Telescope= toc Although these two **telescopes** have different names, they are more similar in the way that they are both **Optical telescopes**. Although from there, you are able to break them down into two different categories: refracting telescope and reflecting telescope. The two telescopes both gather and focus light but the difference between the two is that a refracting telescope uses a lens, while a reflecting telescope uses a mirror.

=History of The Refracting Telescope= The first ever refracting telescope was made in 1608. This was only a model used for a later one created in 1609 that was actually used for scientific studies. It was made by Galileo Galilee so that scientists could watch and study the four moons orbiting Jupiter.

=What is a Refracting Telescope=

[[image:2012grade10/simple-refractor-illustration.jpg]]
Basically, a refracting telescope is two different lens inside of a long tube.

__Large Lens__
The large **lens** on the right side of the telescope is called the objective lens. This is the lens that gathers all the light. The size of this telescope differs the difference between having a good shot of space, to an extraordinary one. This is because when you have a large refracting telescope, this means that the lens will be larger too. This allows more light to be gather, thus giving you a deeper image of space. This could also be known as magnifying or focusing the object in the night sky.

__Small Lens__
The small lens on the left side of the telescope is called the **eyepiece**. This is the lens that magnifys the image. This eyepiece is able to be changed or replaced. You could go from having a 50x magnification, to 100x magnification. It all depends on your desire of how deep and detailed you want to get into space. Although, you always have to keep in mind, that every telescope has its certain limits, and will only be able to be compatable with so many eyepieces.

=How a Refracting Telescope Works= Inside the telescope there is a convex lens and bends the light going through the telscope and brings it into focus. The center of the lens is thicker than the edges, this way the light will bend more at the edges. When the light finally comes together at a focus point, this is where the image is created. Finally, when you look through the eyepiece, because it is a concave lens, it magnifies the total image. media type="custom" key="16601818" In this image below you can see how the light is being bent by the objective lens. As the light travels farther and farther down the tube, the light goes from being very large in size to smaller, and smaller. Because of the decrease of light, it makes the image you see through the eyepiece inverted. This means that the image you see is actually upside down and backwards. This can be changed by putting a different eyepiece of the left side of the telescope. This will change everything from upside down and backwards to right side up and forwards.

A chromatic effect is created in these telescopes due to the different colours passing through it. These colours or "frequencies" can vary from red, blue and green. Each colour bends a little differently, causing weird colours to appear when looking through the telescope. Because of this problem, there is always two lens on a refracting telescope. The objective lens called the achromatic lens is the one that helps to bend the light differently, offsetting the colours appearing and canceling the colours out.

=History of The Reflecting Telescope= The first reflecting telescope was made in 1688 by Isaac Newton. After he had completed his model scientists realized that the reflecting telescope was better than the reflecting telescope because the reflecting telescope uses **mirrors** that create clearer and larger images.

=What is a Reflecting Telescope= A reflecting telescope uses curved mirrors to collect and focus light. The mirror is concaved, having a thinner center that collects and then reflects the light to create an image. Viewing through the eyepiece helps to magnify the image. This telescope is top class for viewing dark images or during dim points in the day. Because of this you are able to see objects that are in space that are one millionth of the distance than the small starts that only a human eye can see.

=How a Reflecting Telescope Works= The reflecting telescope gots its name simply by how it works. The telescope uses a mirror to reflect the light coming in and bounce it back up the tube. The secondary mirror is angled upwards so that once the light has reached it, it will reflect upwards to the eyepiece, where you are then able to see the image. The secondary mirror is parabolic shaped. This means that the mirror would look somehwat like a saucer bowl in that the middle is indented.

=Terrestrial Telescope vs. Astronomical Telescope= Although these two may appear to be similar, when looking at an object they prove that statement false. When looking into an **astronomical telescope** you are actually looking at an image upside down. This is why most people use this type of telescope to look at objects in outer space like stars. Because the telescope has less mirrors this means that when the light does hit a mirror its not going to loose as much light if there were more mirrors, making the image that much better. Then when looking at a **terrestrial telescope**, its the complete opposite. There is an extra mirror added into these telescopes that invert the image again so that when you look at it, it appears upright. This is why people mainly use this telescope for looking at images on earth. To sum it up, a Terrestrial telescope has one more mirror than a Astronomical Telescope so that the image is upright instead of inverted. =Glossary= =References= How a refractor telescope works - YouTube. (n.d.). YouTube - Broadcast Yourself. . Retrieved May 25, 2012, from [] Dictionary. (n.d.). Dictionary Reference. Retrieved May 25, 2012, from [] Refracting and Reflecting Telescopes. (n.d.). ThinkQuest : Library. Retrieved May 25, 2012, from [] Telescope types. (n.d.). Telescopes. Retrieved May 25, 2012, from [] What is a refractor telescope?. (n.d.). Storm The Castle -Creativity, Epic Fantasy, Classical Guitar, video game making, writing, dioramas, terrariums, and more. Retrieved May 25, 2012, from http://www.stormthecastle.com/telescopes/what-is-a-refractor-telescope.htm
 * **Term** || **Definition** ||
 * //Telescope// || An optical instrument for making distant objects appear larger and therefor nearer ||
 * //Optical telescopes// || An astronomical telescope designed to collect and record light from cosmic sources ||
 * //Lens// || Transparent substance(usually glass) changing light rays and for magnification ||
 * //Eyepiece// || The lens in an optical instrument through which the eye views the image formed ||
 * //Mirror// || A reflecting surface ||
 * //Terrestrial telescope// || A refracting telescope having inverting lenses or an eyepiece that presents an erect image ||
 * //Astronomical Telescope// || A telescope having an objective with a long focal length and an eyepiece with a short focal length ||