In contrast to sciences like physics and biology, astronomy is usually based on observation rather than experiments. You can’t, after all, move a star to a more convenient location. This means that astronomers’ instruments have to be as precise as humanly possible.
Astronomical telescopes have been in existence since the beginning of the seventeenth century. Originally a device for use on ships, turning them skywards quickly proved that the universe was more complex than we originally thought. Today, several types of telescope are available, from lightweight, portable scopes made for the home user to massive installations costing millions of dollars.
Shedding Some Light on the Subject
Optical scopes – that is, those that work with visible light – are the most common and best known. Their purpose is simply to display the best image possible at the highest magnification for viewing or photography. They come in three basic varieties, all of which can be found among affordable models intended for the hobbyist. The simplest kind is called a refracting scope, which uses a series of lenses to enhance the view of the user. A reflecting telescope uses a series of curved mirrors instead, which means that they have both advantages and drawbacks compared to refractors. A catadioptric design uses a combination of the two methods, usually in a very compact device.
Examples of each of these types can be found both in huge observatory-based scopes and in smaller models you can set up in your back yard. In addition, different telescopes come with a variety of bases and stands that help you with finding and tracking objects in the night sky. The most common of these is a standard tripod base that lets you rotate the scope vertically and horizontally until it’s aimed where it should be. Equatorial bases are an alternative. These align the scope to the axis of the earth’s rotation, making it easier to track objects for long periods. This is especially useful when it comes to astrophotography.
Optical telescopes are the only type a casual skygazer will typically use. Professional researchers, however, have a wider array of tools at their disposal, including radio and energetic particle telescopes. Each kind helps to reveal more information about bodies such as nebulas and planets – as it turns out, there’s still a whole lot waiting to be discovered up there.
Related Information:
Refractors
Learn more about this common type of telescope.
Astroscan
A basic type of scope intended for use by complete newbies.