A telescope may be called the window to the universe. Over the years, telescopes have come down in price to a level where they -- especially the lower-end models -- are affordable for many consumers. However, there are a number of important factors to consider when buying a telescope, such as the type, size and accessories.
Despite of all the advances made, one thing is clear when it comes to telescopes: the amount of light that gets into the lens is the most important factor, even more so than magnification. Light gives detail and resolution to celestial objects, and without light, there is no vision. A telescope's aperture is the diameter of a telescope's lens or mirror. Generally speaking, the higher this value is, the higher the light-gathering capability will be.
A telescope is a fairly simple tool that simply does one thing -- aids in stargazing and looking at planets. Still, for such a remarkably simple goal, it can be accomplished in various ways. At some point, especially if searching in a serious, science-minded environment, the type of telescope will eventually come into play.
Refractor telescopes are perhaps what many people think of when the word telescope comes to mind. Having the classic, straight design, it is the one most often seen in stores that sell telescopes along with other general merchandise, merely as an afterthought. It works by using lenses to focus light at the other end of the telescope. These are good for producing a clear, sharp image with high resolution.
Reflector telescopes are somewhat different in the path that the light takes, but also have a straight design. Light enters the telescope where it reflects off curved or angled mirrors inside near the bottom of the tube. Those mirrors then reflect the light off a mirror near the top of the telescope and then through a lens. They are known for their display of colors and are often cheaper than refractor telescopes.
A third type of telescope, known as the catadioptric telescope, works in a similar manner to the reflectors by reflecting light off a curved mirror, which then reflects off a mirror at the top of the tube. This mirror sends the light through a hole in the curved mirror and to another mirror, which sends the light through a lens. With these telescopes, the eyepiece is actually angled upward from the main tube.
For those considering getting a telescope with more accessories, such as those that help you see better in the night sky, it is important to consider whether such things are truly necessary. There may be no need to spend the extra money if the skies are sufficiently dark enough. In cities, with ambient night lighting interfering with the celestial sky, these types of accessories may be necessary.