Telescopes

4 Pages 930 Words

Reflecting Telescopes use a mirror to gather light and bring the image to the eyepiece. These telescopes are often referred to as "Newtonians" because they were first conceived of by Isaac Newton. Reflectors utilize a parabolic mirror that reflects the image to a focal point. Since the mirror reflects the image back towards the source, a small secondary mirror set at an angle reflects the light perpendicular to the tube so that the eyepiece is attached to the side of the telescope, rather than the end. Reflectors provide good views of all types of sky objects such as planets, the moon, star clusters, galaxies, nebulae, and multiple star systems. They require some minor maintenance to keep the mirrors in proper alignment. They are the least expensive telescopes and provide the most light-gathering abilities for the dollar. The favorite choice of amateur astronomers everywhere.
• Strengths: Great for viewing faint objects such as galaxies and nebulae, reflectors also provide good general viewing of clusters, planets, the moon and binaries. Affordable.
• Weaknesses: They tend to be more bulky to move about and store. They also require periodic maintenance to keep the optics properly aligned.
Refracting Telescopes use a lens to gather light and bring the image to the eyepiece. These are the type of instruments that most people think of when they think of a telescope. They are fairly maintenance free and generally provide superb images of the moon, planets, star clusters and general sky gazing. They tend to be smaller in aperture than other types so they are not as good for viewing fainter sky objects such as galaxies and nebulae. Good quality refractors tend to be expensive. Beware of cheap refractors!
• Strengths: Great for viewing planets, the moon, star clusters, and splitting binary and multiple star systems. They have the classic telescope appearance.
• Weaknesses: Because of their small aperture they are less well ad...