Best Lab Equipment

Here are some more information for Eyepiece Diameter:

What Are Telescopes and Its Benefit?

A telescope "telescope" is an instrument designed for the observation of remote objects. The term usually refers to optical telescopes, but there are telescopes for most of the spectrum of electromagnetic radiation and for other signal types. An optical telescope is an optical tool that gathers and focuses electromagnetic radiation. Telescopes increase the apparent angular size of distant objects, as well as their apparent brightness. Telescopes work by employing one or more curved optical elements - lenses or mirrors - to gather light or other electromagnetic radiation and bring that light or radiation to a focus, where the image can be observed, photographed or studied. Optical telescopes are used for astronomy and in many non-astronomical instruments.
The main purpose of a telescope is to gather light, i.e. to collect and focus photons. We can think of a telescope then as a "light bucket" - the bigger the bucket, the more photons a telescope can collect.

Types of telescopes:
There are three basic types of telescopes -- Refractors, Newtonian reflectors, and Catadioptrics.

Newtonian Reflector Telescopes:
Newtonians usually use a concave parabolic primary mirror to collect and focus incoming light onto a flat secondary mirror that in turn reflects the image out of an opening at the side of the main tube and into the eyepiece.

Refractor Telescopes:
Refracting telescopes have an objective lens at the front of the tube. The light exits out through the back of the tube to the eyepiece. Since many observations are made high in the sky, a right-angle diagonal is used to avoid neck strain. This also provides an upright image making them suitable for terrestrial observations. A refractor has several advantages over other designs. The tubes are enclosed so that dust and moisture do not enter the tube, they have fixed optics that do not normally require collimation, and they do not have a central obstruction which reduces the light entering the tube. A refractor typically will give higher quality images of planets than other telescopes of similar aperture.

Catadioptric Telescopes:
Telescopes using a combination of both mirrors and lenses are called catadioptrics. There are many different designs. Examples of these are the Schmidt-Cass grain and the Maksutov-Cassegrain. Usually a full aperture lens is used to correct aberrations in a compound reflecting telescope. The corrector lens also increases the performance of the instrument as air currents are eliminated. The main advantage of the design is that, because the light path is folded back on itself, it provides a very portable, short physical length telescope with a long focal length.

Benefit:
1. The aperture of a telescope is several times larger than the aperture of human eye so that the objects that can not be normally seen by unaided eye can be seen. Light- gathering power of a telescope is proportional to the area of its aperture and hence depends on the square of the radius of the mirror. Therefore a 20 cm diameter telescope collects four times more photons than a 10 cm diameter telescope.

2. A telescope can be equipped to record light over a long period of time, by using photographic film or electronic detectors such as photometers or CCD detectors while the eye has no capability to store light. A long-exposure photograph taken through a telescope reveals objects too faint to be seen with the eye, even by looking through the same telescope.

3. A third major advantage of large telescopes is that they have superior resolution, the ability to discern fine detail. Small resolution is good. The resolution is directly proportional to the wavelength being observed and inversely proportional to the diameter of the telescope.

About the Author

For more information on Telescopes visit our http://www.halfvalue.com and http://www.halfvalue.co.uk websites.

If i can, what planets/stars/galaxies...etc will I be able to see with this telescope?

The facts in the scope:

Magnification's not important. If you don't have aperture, or good seeing conditions, you won't be able to see anything decently with any magnification. The most important aspect, when considering a telescope is aperture, which is the size of the primary mirror or lens. I can't really tell very well what type of telescope you're talking about from you're description, but it sounds like a small aperture newtonian reflector, or a small aperture refractor. A telescope like that can be wonderful to learn the night sky with, or to become accustomed to using a scope, but for good planetary or deep sky viewing you'll need at least eight inches of aperture. If you're serious about astronomy, and want to get some of the "wow" factor, I'd recommend a newtonian reflector, or a schmidt cassegrain telescope with at least an eight inch primary mirror.
There are models made by Orion and Meade called "Dobsonian" telescopes which are usually fairly inexpensive in larger apertures. I don't want to scare you away from getting a $229 scope, but I will tell you that if you want to look at things like planet Jupiter through it, all you will really be able to see is a bright spot with four tiny bright specs around it; whereas, with something in an eight inch or larger format, you will be able to see cloud belts, the red spot, and the moons even when they are in transit across the planet.
My first scope was about $229, and it did teach me how to use a telescope, and my way around the night sky, but anyway, here are some links to web sites where you can find dobsonian and schmidt cassegrain telescopes. And remember... the more aperture the better!
http://www.meade.com/
http://www.telescope.com/control/category/~category_id=dobsonians
http://www.celestron.com/c3/category.php?CatID=2

P.S. From what you described up there, it looks like you might be talking about a 76mm refractor (a long thin telescope). 76mm is about 3 inches.
And in those web links, the dobsonians are the ones that go straight down to the floor, the schmidt cassegrains are the short fat ones that are up on mounts. Happy Stargazing.

See Mars pass cosmic beehive in the sky
Space.com: Skywatchers have a chance in mid-April to watch Mars pass a cosmic beehive in the sky. All that is required are clear skies and the right tools — some binoculars or a small, low power telescope — to see the Mars show as darkness falls.

Thanks for visiting!