Meade LX70 R8 8 inch Instruction Manual - Page 12
Choosing an Eyepiece, Using the Bubble Level, Observing by Moving the, Telescope Manually
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outlined above. With this alignment performed, objects first located in the wide-field viewfinder will also appear in the telescope's eyepiece. Choosing an Eyepiece A telescope's eyepiece magnifies the image formed by the telescope's main optics. Each eyepiece has a focal length, expressed in millimeters, or "mm." The smaller the focal length, the higher the magnification. For example, an eyepiece with a focal length of 9mm has a higher magnification than an eyepiece with a focal length of 26mm. Your telescope comes supplied with a 26mm eyepiece which gives a wide, comfortable field of view with high image resolution. Low power eyepieces offer a wide field of view, bright, high-contrast images, and eye relief during long observing sessions. To find an object with a telescope, always start with a lower power eyepiece such as the 26mm. When the object is located and centered in the eyepiece, you may wish to switch to a higher power eyepiece to enlarge the image as much as practical for prevailing seeing conditions. For information about optional eyepieces for the LX70 Series models, see OPTIONAL ACCESSORIES. The power, or magnification of a telescope is determined by the focal length of the telescope and the focal length of the eyepiece being used. To calculate eyepiece power, divide the telescope's focal length by the eyepiece's focal length. For example, a 26mm eyepiece is supplied with the LX70 series. The focal length of the 8" reflector model is 1000mm. Telescope Focal Length ÷ Eyepiece Focal Length = Magnification (Power) Telescope Focal Length = 1000mm Eyepiece Focal Length = 26mm 1000 ÷ 26 = 38.46 The eyepiece power, or magnification is therefore 38X (approximately). Can you ever have too much power? If the type of power you're referring to is eyepiece magnification, yes, you can! The most common mistake of the beginning observer is to "overpower" a telescope by using high magnifications which the telescope's aperture and atmospheric con- ditions cannot reasonably support. Keep in mind that a smaller, but bright and well-resolved image is far superior to one that is larger, but dim and poorly resolved. Powers above 400X should be employed only under the steadiest atmospheric conditions. Most observers will eventually want three or four additional eyepieces to achieve the full range of reasonable magnifications possible with the LX70 telescopes. See OPTIONAL ACCESSORIES. Using the Bubble Level For best telescope performance, the equatorial mount should be properly leveled. A level tripod allows better weight distribution and easier alignment on the night sky. The LX70 mount includes a small bubble level near its base. Adjust the height of each tripod leg until the bubble appears in the center of the circle. Note: Adjusting the tripod on a fully assembled mount can be dangerous. Get the assistance of a friend if attempting to adjust the tripod height while fully assembled. Observing by Moving the Telescope Manually After the telescope is assembled and balanced as described previously, you are ready to begin manual observations. View easy-to-find terrestrial objects such as street signs or traffic lights to become accustomed to the functions and operations of the telescope. For the best results during observations, follow the suggestions below: When you wish to locate an object to observe, first loosen the telescope's R.A. lock and Dec. lock. The telescope can now turn freely on its axes. Unlock each axis separately and practice moving your telescope. Then practice with two unlocked axes at the same time. It is very important to practice this step to understand how your telescope moves, as the movement of an equatorial mount is not intuitive. Use the aligned viewfinder (see ALIGNING THE VIEWFINDER, pg 11) to sight-in on the object you wish to observe. When the object is centered in the viewfinder's crosshairs, re-tight- 12