User manual CELESTRON CG-4 EQUATORIAL MOUNT

[. . . ] · C80-HD Refractor Telescope · C102-HD Refractor Telescope · C114-HD Reflector Telescope · C150-HD Reflector Telescope · CG-4 Equatorial Mount Models #21077 / #21016 / #31027 / #31056 / #91510 INSTRUCTION MANUAL 1 IDENTIFYING PARTS OF FIGURE 1 1. Star Diagonal (Refractors only) Eyepiece Finderscope Finder Bracket Focuser Tube Rings Objective Cap Optical Tube Platform DEC Setting Circle R. A. Accessory Tray Mounting Screws 3. 4. 6. 2. 1. 5. Figure 1A C80-HD & C102-HD 4. 24. Figure 1C CG-4 EQ Mount 3 INTRODUCTION Congratulations on your purchase and welcome to the Celestron world of astronomy. [. . . ] If your telescope does not use a motor drive, all celestial objects in the sky (day or night) will slowly drift out of the field. Even if you are not using a motor drive, polar alignment is still desirable since it will reduce the number of corrections needed to follow an object and limit all corrections to one axis (R. A. ). There are several methods of polar alignment, all of which work on a similar principle, but are performed somewhat differently. For each hemisphere, there is a point in the sky around which all the other stars appear to rotate. These points are called the celestial poles and are named for the hemisphere in which they reside. For example, in the northern hemisphere all stars appear to move around the north celestial pole (see figure 6). When the telescope's polar axis is pointed at the celestial pole, it is parallel to the Earth's rotational axis. Many of the methods of polar alignment require that you know how to find the celestial pole by identifying stars in the area. For those in the northern hemisphere, finding the celestial pole is not difficult. This star, Polaris, is the end star in the handle of the Little Dipper. Since the Little Dipper (technically called Ursa Minor) is not one of the brightest constellations in the sky, it may be difficult to locate, especially from urban areas. If this is the case, use the two end stars in the bowl of the Big Dipper. The position of the Big 10 Dipper will change during the year and throughout the course of the night. When the Big Dipper is low in the sky (i. e. , near the horizon) it may be difficult to locate. Figure 6 Figure 7 To make finding and tracking the stars easier, a rough polar alignment is required. The right ascension (polar) axis should be pointed towards the North Pole (see figure 7). Set the latitude of the telescope to the latitude of your observing location by turning the azimuth adjustment screws (#14) on the mount. The latitude of your observing location corresponds to the altitude that Polaris will appear to be above the horizon. For example, If you are observing from Los Angeles, which has a latitude of 34°, then the celestial pole (and Polaris) will be 34° above the northern horizon. All a latitude scale does then is to point the polar axis of the telescope at the right elevation above the northern (or southern) horizon. Release the DEC clamp and move the telescope so that the tube is parallel to the polar axis. If the declination setting circle is not aligned, move the telescope so that the tube is parallel to the polar axis. 4. 11 5. Using the altitude and azimuth adjustment screws (#14 & #20), move the mount until Polaris is in the field of view of the finderscope. You want to adjust the direction the polar axis is pointing and you are using the telescope to see where the polar axis is pointing. 6. This gets you close to the pole but not directly on it. In order to improve your accuracy for more serious observations and photography Celestron offer an optional Polar Axis Finderscope (#94221) that fits into the polar axis of the mount. Aligning the R. A. [. . . ] Celestron warrants this telescope to be free from defects in materials and workmanship for two years. Celestron will repair or replace such product or part thereof which, upon inspection by Celestron, is found to be defective in materials or workmanship. As a condition to the obligation of Celestron to repair or replace such product, the product must be returned to Celestron together with proof-of-purchase satisfactory to Celestron. The Proper Return Authorization Number must be obtained from Celestron in advance of return. [. . . ]