TELESCOPES

BY: Leroy Alan Nahay

Why do we need telescopes?

Have you ever wondered why can’t we see the print on something at 100yards away when we can at a foot away from us?

The reason we cant see the fine print at this distance is because it doesn’t make up enough space in front of our eye.

Example: if you take a picture of something and cant read or make out what it is because of the distance its because there is not enough pixels (or space) to make out the writing.

The Purpose of Telescopes

The technology in telescope are used for multiple applications today.

The reason we use telescopes is to observe and retain information about something without getting ourselves involved, waste time, or if it is out of reach.

What makes up a telescope? The three main telescopes I'm

going to talk about are the refracting telescope, the reflecting telescope, and the catadioptric telescope.

Refracting Telescope: Objective lens, eye piece

Reflecting Telescope: Primary mirror, secondary mirror, eye piece.

catadioptric telescope: focuser, secondary mirror, primary mirror, correcting lens.

The Refracting TelescopeRefracting telescopes are the most common telescopes.They were the first optical telescopes made in 1608Refracting telescopes are also the most basic optical telescopes, with just having two main pieces the primary lens and secondary lens. The primary lens gathers a large amount of light more than the human eye can and the secondary lens then focus’s the light for the human eye.

Where Refracting Telescopes are Used

Binoculars Rifle scopes Cameras Glass’s Most consumer optical telescope devices.

The Reflecting Telescope

Reflecting telescope’s rely on curved mirrors to reflect light

The reflecting telescope was invented in the 17th century reflecting telescopes are used more for astronomy than refracting telescopes because they eliminate chromatic aberration, which is the distortion of the lens to focus all the colors to the same convergence point.

chromatic aberration

Catadioptric Telescope

Combines a combination of mirrors and lenses They have a higher margin of error due to more pieces

involved in the telescope A lot of armature astronomers use the telescope because

they are a lot more compact than reflecting or refracting telescopes and can be moved easier from place to place

How Telescopes zoom in/out

A telescope with a shorter focal length has a stronger optical power because it bends the light more strongly.

A focal plane is the area between the primary and secondary lens.

Also the magnification can be changed by the eye piece power of magnification.

Doubling the diameter of the lens increases the light gathering power

Magnification

To figure out the Magnification you have to take the focal point of the objective lens divided by the focal point of the eye piece lensSo if the focal length of the objective lens is 50cm and the focal length of the eye piece lens is 5cm you get 50/5=10x

Limitations of Refracting Telescopes

Briefly stated before refracting telescopes have a problem called “chromatic aberration” this is when the light that is passed through the lenses comes into focus at different points and makes the image blurry and/ or colored awkward. This effect image quality and clarity

Aperture

Aperture is a big rule in clarity for the object your trying to focus on.

A narrow aperture will give you a image the is clear for the most of the image but isn't as clear as it could be on a specific object.

A Wide aperture will give you a sharp focus on what the lens is focusing on and blurred for the rest of the image.

Citations Pictures http://s1.hubimg.com/u/1445852_f520.jpg Title page http://images.google.com/imgres?imgurl=http://www.garone.net/tony/telescopes.gif&imgrefurl=http://

www.garone.net/tony/mehistree.html&usg=__s6Hlis-AgkJVl_sEam8_Qtks8G4=&h=377&w=383&sz=14&hl=en&start=24&itbs=1&tbnid=Kche6sPDLW2YjM:&tbnh=121&tbnw=123&prev=/images%3Fq%3Dtelescopes%26start%3D21%26hl%3Den%26sa%3DN%26gbv%3D2%26ndsp%3D21%26tbs%3Disch:1 3 different telescopes

http://www.company7.com/orion/graphics/NewtonianLightPath649499.jpg reflecting telescope http://stellafane.org/tm/atm/general/images/atm_type_cat.gif catadioptric telescope http://en.wikipedia.org/wiki/Refracting_telescope Refracting telescope http://en.wikipedia.org/wiki/File:Chromatic_aberration_%28comparison%29.jpg chromatic aberration http://images.google.com/imgres?imgurl=http://lcogt.net/files/jbarton/galilean.png&imgrefurl=http://

lcogt.net/en/book/refracting-telescopes&usg=__oC4dbVlcxnfSRkUH7HcpxZO4fDg=&h=947&w=1956&sz=166&hl=en&start=1&um=1&itbs=1&tbnid=oiH513pF2nf6xM:&tbnh=73&tbnw=150&prev=/images%3Fq%3Dhow%2Btelescopes%2Bmagnify%26um%3D1%26hl%3Den%26sa%3DN%26tbs%3Disch:1 magnification

Videos:http://www.youtube.com/watch?v=nkl8RMPi5Mo&feature=related earth zoom in http://www.youtube.com/watch?v=dX4MspMoWiw&feature=related earth zoom out http://www.youtube.com/watch?v=gsAN2fM_VS0&feature=related making a telescope

Information: http://science.howstuffworks.com/telescope1.htm http://en.wikipedia.org/wiki/Reflecting_telescope