How To Use a Telescope

Sure, you've seen plenty of pictures on the Internet or on television of the moon's heavily cratered surface, Jupiter's massive red spot, and Saturn's dazzling rings, but seeing these through a telescope gives you a whole new perspective of the universe and a greater appreciation for its' many wonders.

  1. Before learning how to use a telescope, familiarize yourself with the type of telescope you purchased.
    • Telescope types: There are three types of telescopes: a reflector telescope (also known as a Newtonian), which uses a large mirror at the back of the telescope to gather light; a refracting telescope, which uses a lens at the front of the telescope to gather light; and a catadioptrics telescope, which is a hybrid of the two. Refractor telescopes are the most commonly used, although both refractors and reflectors provide excellent images.
    • Magnification and Aperture: Magnification is not as important as aperture. Aperture is the diameter of the main lens that collects the incoming starlight. The bigger the lens, the more light that comes in, and the brighter the images are.
    • Mounts: Determine how your telescope is mounted. It's either altazimuth ("alt-az") or equatorial. Altazimuth mounts are simple up-down, left-right mounts, allowing the telescope to move simultaneously on both axes. Equatorial mounts also have two axes, but are designed to have one axis point to the North Star. Alt-az mounts are intuitive to use and less expensive.
  2. Learn the sky. Take the time to look at and study star maps. There are several good books and monthly publications with maps available. Star maps are also available on the Internet.
  3. Set up the telescope. Place the telescope outside, preferably on grass, approximately 30 minutes before you plan on using it. This allows for temperatures to equalize. Avoid using the telescope on a windy night-the air should be still. Never use your telescope through a window.
  4. Position the telescope so that everything is at right angles. The telescope should be placed on flat ground, and the tripod legs should be fully extended.
  5. If you have an equatorially mounted telescope, align it. Tilt the telescope so that one axis (the right ascension axis) points to the North Star by turning the latitude adjustment knob. Once you find the North Star through the eyepiece, tighten the latitude lock knob. Next, tilt the telescope so that the declimation axis is on the star or object you are trying to track.
  6. Align the finder scope. The finder scope must be aligned precisely with the telescope so they both point to the exact same spot. First, insert the lowest power eyepiece and point the telescope at a bright planet or the moon. Once you get it centered in the eyepiece, lock it down. Now, loosen the three thumbscrews holding the finderscope in place and look through the eyepiece, which should have a cross hair or "X". Align the planet on the cross hair and tighten the screws so it holds the finderscope in place.
  7. Enjoy you evenings looking at the night sky through your telescope!

 

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