There are of course many different types of telescopes. There are three main types of telescopes; reflectors, refractors and catadioptric. Reflectors use mirrors to reflect the light captured by the aperture. Refractors use lenses to convey the image caught at the aperture to the opening for the eyepiece. Catadioptric telescopes are telescopes that combine together mirrors and lenses. There are many pros and cons of each type of telescopes. I'll talk about these in later posts.
The telescope I ordered is a 90mm Maksutov-Cassegrain. This is a catadioptric type of telescope. The 90mm corresponds to the diameter of the aperture of the telescope. This is the most important aspect of a telescope. The larger the aperture, the more light the telescope absorbs and hence the more fainter and further objects it can reveal.
Another important factor is the focal length of the telescope. The longer this is the more power of magnification it provides. The magnification is the first thing people think of when they think of telescopes and they believe this is the metric on which to evaluate a telescope. This is not true.
The magnification of a telescope equals the focal length of the telescope divided by the focal length of the eyepiece. Eyepieces are changeable. Astronomers typically have sets of different eyepieces to attach to the telescope depending on what they want to see. Eyepieces each have a focal length and a field of view. There is no point in trying to get the highest possible magnification, which means getting the eyepiece with the smallest focal length. This is because there is a limit to the amount of magnification a telescope can handle. The limiting factor is our old friend, the aperture. There is only so much detail (i.e. light) that exists in the image caught by the telescope's main mirror or lens (according to the aperture size). There is no point in trying to magnify beyond the detail that the telescope reveals. This will give you a blurred image. Another thing to consider is the field of view of the eyepiece being used. I'll talk more about eyepieces in future posts.
My telescope-to-be (isA) is a catadioptric type. It is a very compact model. You can see it here...
I didn't order the tripod you see in the pic.
This telescope should be able to see, believe it or not, the red spot on Jupiter and the dust ring around Saturn. Of course I'm going to go out to the desert or somewhere with no light or air pollution.
Just hope I get the scope intact soon isA...
When I do I won't stop showing it off :p
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