Telescopes are an arrangement of lenses or mirrors or both that collects visible light, allowing direct observation or photographic recording of distant objects. A telescope can be used in many ways, such as observing stars, moons, planets, observing the city from a tall building or observing wildlife. Not all telescopes are the same, some are better than others. There are three different types of telescopes. Reflective which uses two mirrors instead of lenses, catadioptric (CAT) which combines lenses with two mirrors and reflectors. In this article I will talk about a refractor telescope and explain the different terms that describe a telescope as well as special features that make a telescope a good choice for what you need. Refractors are a type of optical telescope that uses a lens as an objective to form an image at the top. A refractor telescope is made of glass optical elements, like a camera lens. It had a long tube with glass lenses in the front. They are essentially similar to a large camera lens, but use fewer lens elements. Refractors are high quality and known for their high contrast, excellent imaging capability and relative durability. They can produce views of bright, highly detailed objects (the moon and planets) that are significantly better than corresponding mirror telescopes. The main advantages of a refractor are that it is easy to hold, easy to use, and is capable of observing both the world and the stars. One problem with refracting telescopes is that there is a frequency requirement for refraction, so the amount of refraction on each lens surface depends on the wavelength. Therefore, different wavelengths concentrate at slightly different points. Causes objects such as stars to be surrounded... in the center of the paper... ope and use the telescope simulator. We learned that there are many different types of telescopes such as refractors, reflectors, and catadioptics. Also there are many different terms to describe a telescope. Using the simulator, we had to determine which inch of aperture, which kilometer of eyepiece, and focus adjustments to get the best image of the moon/Saturn/cluster. Once you get the best image, in the bottom left corner. Shows light gathering power (LGP), resolution, magnification and field of view. The light gathering power is the most important feature. The so-called aperture gain is the ability of a telescope to collect much more light than the human eye. Works Cited http://www.chuckhawks.com/astronomy_definitions.htm http://www.chuckhawks.com/telescope_basics.htm http://starizona.com/acb/basics/equip_wichisbest.aspx