Telescopes are an arrangement of lenses or mirrors or both that capture 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, looking at 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 a lens with two mirrors and reflectors. In this article I will talk about a refracting telescope and explain the terms of the different terms that describe a telescope in addition to the special features that make a telescope a good choice for what you need it for. Refractors are a type of optical telescope that uses a lens as the upper objective to form an image. A refracting telescope is made of glass optical elements, like a camera lens. There was a long tube with glass lenses in the front. They are essentially similar to a large camera lens, but use fewer lens elements. The 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 maintain, easy to use and is capable of global observation as well as stargazing. A problem with refractive telescopes is that there is a frequency requirement for refraction, so the amount of refraction on each surface of the lens depends on wavelength. So different wavelengths focus at slightly different points. This causes objects like stars to be surrounded...... middle of paper ......op and use the telescope simulator. We learned that there are many different types of telescopes, such as refractors, reflectors, and catadioptics. Additionally, there are many different terms to describe a telescope. Using the simulator, we had to figure out what inch of aperture, mile of eyepiece, and focus settings to get a better image of the moon/Saturn/cluster. Afterwards, we get the best image, in the lower left corner. It displays light gathering power (LGP), resolution, magnification and field of view. The light gathering power is the most important feature. We talk about aperture gain because it is the ability of a telescope to collect much more light than the human eye. http://starizona.com/acb/basics/equip_whichisbest.aspx