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Telescope Basics

Telescopes collect light ____ Eye pieces magnIfy

For our purpose here the two optical assemblies will be the Refractor Telescope and the Reflector Telescope on a Telescope Mount. Here we will discuss the basic principles or how these two types of telescopes work we will discuss mounts on a different page

Just Remember

Reflectors have mirrors and Refractors don’t. It really is as simple as that to identify them. Unfortunately that is where simplicity ends.

Next,

Realize that a telescope, regardless of the type is a light bucket! That is to say "the primary function of All telescopes is to gather data, then focus that data for use. For our purpose that data will be light."

The diameter, or aperture, is the limiting factor of how much light a scope can collect. The larger diameter the scope the more you get to see.

The eyepiece is what determines the magnification of the telescope. How much magnification a scope is operating at depends on what eye piece you have in the scope at the time!

The eye piece is an intricate part of the telescope system. I can't stress this enough. Buy the best eye pieces you can afford at the time ! The eye piece transfers from scope to scope, eye pieces are what regulates the magnification of your scope, they make a huge difference in what you see and what you don't. They will always hold their value! If I got rid of all my scopes tomorrow, I would keep my eye pieces. Read more about the Telescope Eye Piece here

Two types of telescopes

Galileo used a refractor (no mirror)The pirates used refractor type scopes. They are basically a tube with a magnifying glass on one end and a lenses on the other end that you look through. (we will get into technical stuff later.)

Most telescopes you see used today are the reflector (mirror) type. Again you start with a tube but there is a mirror on one end that collects the light focuses it to a narrow beam that hits another mirror that shoots it into your eyeball…Cool huh?

 Okay pick one!  What? Still don’t know what you want?

 Okay I’ll get serious for a minute. There really are many, many styles of telescopes.Two basic types, but a whole lot of styles and combination of styles. All of them invented for different needs or desires of the end user. Once again, were back to the question, what would you like your Telescope to do? To help you answer that question lets look at some

Telescope Basics that apply to all scopes

Diameter or aperture of the telescope is the key to how far out there you can see!. Aperture is the single most limiting factor of a telescope. Clarity of the atmosphere being second. This is why the majority of the large research telescopes are humongous Reflector type telescopes placed as high as they can get them! Usually on top of a mountain in a dark area.The air is less polluted the higher you go.

Remember; "the primary function of All telescopes is to gather data, then focus that data for use. For our purpose that data will be light." Everything else enhances the scopes ability to modify the light the telescope is providing.

Focal Length Very basically, focal length is not how long your scope is, but how far the incoming light has to travel from the entrance of the telescope to your eye. Hence focal length. Or sometimes referred to how fast the telescope is. This is the time it takes light to travel that optical path. So, a telescope with a shorter optical path is faster than a scope with a longer optical path. This is known as an F Ratio. So a scope with a focal length of F4 will be a faster scope than an F10. That is as far as we will take that for now. You will need to learn more about Focal Lengths and F ratios later and how they affect the usability of your first scope.

Magnification Very basically is the ability to make an image larger in appearance (not in physical size) in order to see more detail. The higher magnification the more detail. The degree of magnification is the difference in power you give your telescope to magnify the image! At most star parties you can here people calling out "More Power"as we try to push our scopes to there limits <G> Keep in mind that higher magnification is not always a good thing. To see more some times it is better to back off an go wider. A good view through a scope is usually achieved with the best combination of scope with eyepiece depending on atmospheric conditions.

The Eyepiece: Okay, I don't how to simplify the eyepiece. I guess you could say it is like a little telescope you put in your big telescope? The eye piece is what makes a telescope a telescope. Other wise they are just a magnifying glass or a make up mirror. The telescope collects the data and the eye piece is what controls that data and how it is viewed by you. Here is a great article on the eye piece.

The Telescope Mount: The mount holds the telescope so you don't have to. That's simple enough. With that it should hold it pointed where you want, as long as you want, move with the object its pointed at and do all this with little or no vibration. More on Mounts

To recap: The optic tube or tube assembly gathers light, focuses that light to an eyepiece. The eyepiece controls how that light is delivered for you to process. This makes up the telescope that is attached to a telescope mount that controls where your scope is pointed.

That's about simplified as you can get for a telescope description!

Lets go to Telescope Mount Basics

Back to Types of Astronomy