User manual ORION TELESCOPES & BINOCULARS 09801

[. . . ] INSTRUCTION MANUAL Orion Observer 70mm Altaz ® TM #9801 Altazimuth Refractor Telescope Customer Support (800) 676-1343 E-mail: support@telescope. com Corporate Offices (831) 763-7000 Providing Exceptional Consumer Optical Products Since 1975 P. O. Box 1815, Santa Cruz, CA 95061 IN 095 0898 Finder scope Finder scope bracket Focuser drawtube Eyepiece Star diagonal Focus knob Altitude micromotion thumbwheel Altitude micromotion rod Objective lens Dew cap/glare shield Yoke knob Altitude lock knob Altazimuth yoke mount Azimuth lock knob Tripod leg attachment bolt Accessory tray Accessory tray bracket Tripod leg Leg lock thumbscrew Figure 1. Observer 70mm Altaz Parts Diagram 2 Congratulations on your purchase of a quality Orion telescope. Your new Observer 70mm Altazimuth Refractor is designed primarily for astronomical viewing, but can also be used for terrestrial observation (with the recommended addition of an image-erecting prism). If you have never used a telescope before, we would like to welcome you to amateur astronomy. [. . . ] (Always use the lowest-power eyepiece available for locating an object, then you can switch up to higher powers if desired. ) 1. Fine adjustments in the telescope's vertical position can be made by rotating the altitude micro-motion thumbwheel. Fine adjustments in the azimuth position can be made by applying slight sideways pressure to the back end of the telescope (make sure the azimuth lock knob is slightly loosened). Telescope focal length ÷ Eyepiece focal length = Magnification For example, if you're using this telescope, which has a focal length of 700mm, and a 25mm eyepiece, the power would be 700 ÷ 25 = 28x. We recommend having a selection of several eyepieces of different focal lengths, so that you can choose the optimal magnification, brightness level, and contrast for each object and for different observing conditions. Useful Limit of Magnification Every telescope has a useful limit of power of about 45x-60x per inch of aperture (diameter of objective lens). Claims of higher power by some telescope manufacturers are a mislead- 5 ing advertising gimmick and should be dismissed. The Observer 70mm Altazimuth Refractor, with its 70mm-diameter (2. 8") objective lens, is capable of a maximum useful magnification of about 160x. Any higher and the images will virtually always appear very faint and fuzzy. As a general rule, if the image you see is not crisp and steady, reduce the magnification by switching to a longer-focal-length (lower-power) eyepiece. A small but well-resolved image will show more detail and be more rewarding than a dim, fuzzy, over-magnified one. Camera Attachment A 35mm single-lens reflex (SLR) camera body can easily be attached to the Observer 70mm enabling you to take pictures through the telescope. All that is needed is one additional part, called a T-ring, which is specific to your model of camera (see the Orion catalog for selection). Also remove any lenses that may already be attached to your camera body. The T-ring, with your camera attached, threads directly onto the end of the telescope. When used in this configuration, the Observer 70 acts as a 700mm telephoto lens (the focal length of the telescope). In conditions of good seeing, star twinkling is minimal and images appear steady in the eyepiece. Also, seeing generally gets better after midnight, when much of the heat absorbed by the Earth during the day has radiated off into space. Especially important for observing faint objects is good "transparency"--air free of moisture, smoke, and dust. Transparency is judged by the magnitude of the faintest stars you can see with the unaided eye (6th magnitude or fainter is desirable). Tracking Celestial Objects Celestial objects appear to move slowly across the sky because of the rotation of the Earth on its polar axis. When you observe an object through the telescope, you'll see it drift gradually across the field of view. To keep the object centered in the field, give the tube a light tug or push in altitude and azimuth as needed (make sure the altitude and azimuth lock knobs are slightly loosened). Objects will appear to move faster at higher magnifications, when the field of view is narrower. How to Find Interesting Celestial Objects To locate celestial objects with your telescope, you first need to become reasonably familiar with the night sky. [. . . ] Keep the objective lens cap on the front of the telescope when it is not in use. The optical tube is aluminum and has a smooth painted finish that is fairly scratch-resistant. Smudges on the tube can be wiped off with a soft cloth and a household cleaner such as Windex or Formula 409. Cleaning the Optics A small amount of dust or a few specks on the glass objective (main) lens will not affect the performance of the telescope. [. . . ]