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If this website whets your appetite for exploring the sky further, you may be thinking about buying your own telescope. The good news is that many excellent amateur telescopes are now on the market, and prices are much lower than they were 20 years ago. The bad news is that a good telescope is still not inexpensive, and requires some research to find the model that is best for you. The best sources of information about personal telescopes are the two popular-level magazines published for amateur astronomers, Astronomy and Sky & Telescope. Both carry regular articles of advice, reviews, and ads from reputable telescope dealers around the country.
In some ways, choosing a telescope is like choosing a car: personal preference can play a major role in the decision. A certain shape or brand name may be important to some car buyers, but no big deal to others. In the same way, some of the factors determining which telescope is right for you depend on personal preferences:
- Will you be setting up the telescope in one place and leaving it there, or do you want an instrument that is portable and can come with you on camping trips? Does it have to be carried some distance by a person, or can it get to its destination in a car?
- Do you want to observe the sky with your eyes only, or do you want to take photographs?
- What sorts of objects will you be observing? Are you interested primarily in comets, planets, star clusters, or galaxies? Or do you want to observe all kinds of celestial sights?
You may not know the answers to some of these questions yet. For this reason, our number-one recommendation is that you "test-drive" some telescopes first. Most communities have amateur astronomy clubs that sponsor star parties open to the public. The members of these clubs often know a lot about telescopes and can share their ideas with you. Many clubs in the country are also listed once a year in Sky & Telescope and Astronomy magazines.
Furthermore, you may already have an instrument like a telescope at home. Many amateur astronomers recommend starting your survey of the sky with a good pair of binoculars. These are easily carried around and can show you many objects not visible (or clear) to the unaided eye.
When you are ready to purchase a telescope, you might find the following useful:
- The key characteristic of a telescope is the aperture of the main mirror or lens; when someone says they have a 6-in. or 8-in. telescope, they mean the diameter of the collecting surface. The larger the aperture, the more light you can gather and the fainter the objects you can see or photograph, as discussed before.
- Telescopes of a given aperture that use lenses (refractors) are typically more expensive than those using mirrors (reflectors). Mainly because both sides of a lens must be polished to great accuracy. And, because the light passes through the lens, it must be made of high-quality glass throught. In contrast, only the fron surface of a mirror must be accurately polished.
- Magnification is not one of the criteria on which to base your choice of a telescope. Since the magnification of the image is done by a smaller eyepiece, the magnification can be changed by changing eyepieces. However, a telescope will magnify not only the astronomical object you are viewing, but also the turbulence of the Earth's atmosphere. If the magnification is too high, your image will shimmer and shake and be difficult to view. A good telescope will come with a variety of eyepieces that stay within the range of useful magnifications.
- The mount of a telescope is one of its most critical elements. Because a telescope shows a tiny field of view which is magnified significantly, even the smallest vibration or jarring of the telescope can move the object you are viewing around, or out of your field of view. A sturdy and stable mount is essential for serious viewing or photography. More sturdy means less portable though.
- A telescope requires some practice to set up and use effectively. Don't expect everything to go perfectly on your first try. Take some time to read the instructions. If there is one near you, use your local amateur astronomy club as a resource.
Most amateur telescopes have an aperture of 50-60 mm and usually provide a magnification of about X 100.
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