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Objects located below the 0-0 line of the Dec. circle carry minus Declination coordinates. Each division of the Dec. represents a 1° increment. The R.A. circle runs from 0hr to (but not including) 24hr, and reads in increments of 5min. Note that the R.A. circle (17, Fig. 5) is double-indexed, i.e., there are 2 series of numbers running in opposite directions around the circumference of the R.A. circle. The upper series of numbers (increasing counterclockwise) applies to observers located in the Earth’s Northern Hemisphere; the lower series of numbers (increasing clockwise) applies to observers located in the Earth’s Southern Hemisphere. With the telescope aligned to the pole, center an object of known R.A. in the telescopic field. Then turn the R.A circle, which can be rotated manually, until the R.A. coordinate of the object is correctly indicated by the R.A. pointer. As long as the telescope’s motor drive remains “ON,” the R.A. pointer will then correctly indicate the R.A. of any object at which the telescope is pointed throughout the duration of the observing session. To use the circles to locate a particular object, first look up the celestial coordinates (R.A. and Dec.) of the object in a star atlas. Then loosen the R.A. lock and turn the telescope to read the correct R.A. of the desired object; lock the R.A. lock onto the object. Next, turn the telescope in Declination to read the correct Declination of the object. If the procedure has been followed carefully , and if the telescope was well-aligned with the pole, the desired object should now be in the telescopic field of a low-power eyepiece. If you do not immediately see the object you are seeking, try searching the adjacent sky area, using the R.A. and Dec. slow-motion controls to scan the surrounding region. Keep in mind that with the 26mm eyepiece, the field of view of the telescope is less than 1°. Because of its much wider field, the viewfinder may be of significant assistance in locating and centering objects, after the setting circles have been used to locate the approximate position of the object. Pinpoint application of the setting circles requires that the telescope be precisely aligned with the pole. Refer to the preceding section on “Precise Polar Alignment,” page 20 for further details. The setting circles may be used with or without an optional motor drive system. As you track the object, whether by turning the R.A. slow-motion control knob or using an optional motor drive system, the setting circles keep position with the object. - 23 - 9. Observing with the Telescope Meade APO telescopes permit an extremely wide array of serious observational opportunities. Even in normal city conditions, with all of the related air and light pollution, there are a good many interesting celestial objects to observe. But to be sure, there is no substitute for the clear, steady, dark skies generally found only away from urban environments, or on mountain tops: objects previously viewed only in the city take on added detail or are seen in wider extension, or even become visible at all for the first time. The amateur astronomer is faced typically with two broadly defined problems when viewing astronomical objects through the Earth’s atmosphere: first is the clarity, or transparency, of the air and, secondly the steadiness of the air. This latter characteristic is often referred to as the quality of “seeing.” Amateur astronomers talk almost constantly about the “seeing conditions,” since, perhaps ironically, even the clearest, darkest skies may be almost worthless for serious observations if the air is not steady. This steadiness of the atmosphere is most readily gauged by observing the “twinkling” of the stars: rapid twinkling implies air motion in the Earth’s atmosphere, and under these conditions resolution of fine detail (on the surface of Jupiter, for instance) will generally be limited. When the air is steady, stars appear to the naked eye as untwinkling points of unchanging brightness and it is in such a situation that the full potential of the telescope may be realized: higher powers may be used to advantage, closer double stars are resolved as distinct points and fine detail may be observed on the Moon and planets. Several basic guidelines should be followed for best results in using your telescope: 1. Try not to touch the eyepiece while observing. Any vibrations resulting from such contact will immediately cause the image to move. 2. Allow your eyes to become “dark adapted” prior to making serious observations. Night adaptation generally requires about 10 to 15 minutes for most people. 3. Let the telescope “cool down” to the outside environmental temperature before making observations. Temperature differentials between a warm house and cold outside air require about 30 minutes for the telescope’s optics to regain their true and correct figures. During this period, the telescope will not perform well. A good idea is to take the tele...

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