Assessments - 2, GPA: 4.5
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Facilidade de uso
Place the optical tube assembly roughly in the center of the cradle rings and close the rings over the tube. Then tighten the cradle ring lock knobs (15) to a firm feel; do not overtighten these knobs. Please note that you may want to change the rotational position of the optical tube to gain a more comfortable observing position of the focuser (17). This adjustment may be performed several times in one observing session, as desired. • Insert the 25mm eyepiece (19) into the focuser, and tighten the focuser thumbscrew (18) to secure the eyepiece. The telescope is now fully assembled. Before it can be properly used, however, the telescope must be balanced and the viewfinder aligned. Balancing the Telescope In order for the telescope to move smoothly on its mechanical axes, it must first be balanced about the 2 telescope axes: the polar axis (10, Fig. 1c) and the Declination axis (21, Fig. 1c). All motions of the polar aligned telescope (more on this later) take place by moving about these two axes, separately or simultaneously. To obtain a fine balance of the telescope, follow the method below: • Loosen the R.A. lock (22, Fig. 1c) and rotate the telescope so that the counterweight shaft (6, Fig. 1c) is parallel to the ground (horizontal). • Slide the counterweight along the counterweight shaft until the telescope remains in one position without tending to drift down in either direction. Then tighten the counterweight lock knob (7, Fig. 1c), locking the counterweight in position. • Lock the R.A. lock (22, Fig. 1c), and unlock the Declination lock (23, Fig. 1c). The telescope will now turn freely about the Declination axis. Loosen the cradle ring lock knobs (15, Fig. 1e) so that the main tube in the cradle rings slides easily up-or-down in the cradle rings. Move the main tube in the cradle rings until it is balanced rotationally about the Declination axis. Re-lock the knobs (15, Fig. 1e). The telescope is now properly balanced on both axes. Alignment of the Viewfinder The wide field of view provided by the 5 x 24mm viewfinder permits easy object sighting prior to observation in the higher-power main telescope. The 5 x 24 Viewfinder (24, Fig. 1a) and viewfinder bracket (20, Fig. 1a) attaches to the telescope tube assembly as described above (see Fig. 1a). In order for the viewfinder to be functional, however, it must be aligned to the main telescope, so that both the viewfinder and main telescope point at the same position in the sky. With this simple alignment performed, finding objects is greatly facilitated, since you will first locate an object in the wide-field viewfinder, then you will look in the eyepiece of the main telescope for a detailed view. To align the viewfinder follow these steps: • Remove the telescope front dust cover (25, Fig. 1e), and the dust covers of the viewfinder. • Place the low- power (25mm) eyepiece into the focuser of the main telescope. • Unlock the R.A. lock (22, Fig. 1c) and the Dec. lock (23, Fig. 1c) so that the telescope turns freely on both axes. Then point the main telescope at some well-defined land object (e.g. the top of a telephone pole) at least 200 yards distant, and re-lock the R.A and Dec. axes. Turn the flexible cable controls, (3, Fig. 1e) and (4, Fig. 1e), to center the object in the telescopic field. • With the front of the viewfinder already centered in the front bracket ring, look through the viewfinder and loosen or tighten, as appropriate, one or more of the rear viewfinder bracket ring thumbscrews (26, Fig. 1a) until the viewfinder’s crosshairs are likewise centered on the object previously centered in the main telescope. – 8– • Check this alignment on a celestial object, such as a bright star or the Moon, and make any refinements necessary, using the method outlined above. With this alignment performed, objects first located in the wide-field viewfinder will also be centered in the main telescope’s field of view. (Note: The viewfinder presents an image which is upside-down.) UNDERSTANDING CELESTIAL MOVEMENTS AND COORDINATES Understanding where to locate celestial objects, and how those objects move across the sky is fundamental to enjoying the hobby of astronomy. Most amateur astronomers adopt the simple practice of “star-hopping” to locate celestial objects by using star charts or astronomical software which identify bright stars and star patterns (constellations) that serve as “road maps” and “landmarks” in the sky. These visual reference points guide amateur astronomers in their search for astronomical objects. And while star- hopping is the preferred technique, a discussion of using setting circles for locating objects is desirable since your telescope is provided with this feature. However, be advised, compared to star-hopping, object location by use of setting circles requires a greater investment in time and patience to achieve a more precise alignment of the telescope’s polar axis to the celestial pole. For this reason, in part, star-hopping is popu...