User manual BUSHNELL 78-4501

[. . . ] Most noted features are its dark stripes or bands both above and below its equator. Look at different times of the year and try to catch a glimpse of the white polar ice caps. Venus--Just like the moon, Venus changes phases from month to month. At times Venus appears brilliantly in the night sky, just as if you were looking at a distant crescent moon. Nebulae--The Great Orion Nebula is a very well known night sky object. [. . . ] You should always start viewing with the lowest power eyepiece, which in this case is the 20 mm lens. Note: the base power of each eyepiece is determined by the focal length of the telescope objective lens. A formula can be used to determine the power of each eyepiece: telescope OBJECTIVE lens focal length divided by EYEPIECE focal length = MAGNIFICATION (e. g. Using the 20 mm lens, a sample calculation would look like this: 900 mm / 20mm = 45x or 45 power. Telescope models will vary in focal length. ) Included with this telescope is a Barlow lens. Barlow lenses are used to double or triple the power of your telescope. Using the example above, your 3x Barlow lens would give you a total power of 135x or 135 power. The magnification calculation would look like this: 900 mm/ 20mm =45 power. After selecting the desired eyepiece, aim main telescope tube at a land-based target at least 200 yards away (e. g. Fully extend focusing tube by turning Rack and Pinion Focusing Mechanism. While looking through selected eyepiece (in this case the 20 mm), slowly retract focusing tube by turning Rack and Pinion Focusing Mechanism until object comes into focus. 2. (see Focusing Telescope section) Looking through Wide Field Finderscope, alternate tightening each Finderscope Adjustment Screw until crosshairs of Wide Field Finderscope are precisely centered on the same object already centered in Main Telescope Tube's field of view. Now, objects located first with the Wide Field Finderscope will be centered in the field of view of the main telescope. 2. 3. Never Look Directly At The Sun With Your Telescope Permanent Damage To Your Eyes May Occur 7. HOW TO USE YOUR NEW TELESCOPE (CONTINUED) Understanding the Equatorial Mount The Equatorial Mount is designed to move in any direction. It can be set to allow manual controls to track the movements of celestial bodies across the sky. This is referred to as diurnal movement: movement of celestial bodies in the direction opposite to that of the earth's rotation and around the earth's axis. By aligning the telescope's polar axis at celestial North, you will place the telescope parallel with the earth's axis and thus be able to locate stars in the sky based on star atlas information. Loosen the Declination Lock Knob and rotate the telescope around the declination axis until the arrow on the declination scale points to 90 degrees. Loosen the Latitude Lock Knob and set the latitude scale to the correct latitude for your area. You will probably notice that Polaris is not dead center in the Finderscope's field of view. This is probably because your telescope is not absolutely level with the ground. Loosen the Horizontal Axis Lock Knob again and turn the telescope so that it is directly aimed at Polaris. Therefore, the sighting of stars will have to be slightly adjusted as you locate them in the heavens. 2. LATITUDE N N EARTH'S AXIS (CELESTIAL AXIS) POLAR AXIS S S POLAR AXIS & EARTH'S AXIS 8. M ENJOYING YOUR NEW TELESCOPE 1. [. . . ] The reason the sky seems to move daily just as the sun and the moon "move" across our sky is that the earth is rotating about its axis. As a result you may notice that after a few minutes or a few seconds depending on what power you are viewing at, the objects in your telescope will move. At higher magnifications especially, you will notice that the moon or Jupiter will "race" right out of the field of view. To compensate, just move your telescope to "track" it in the necessary path. 9. M HELPFUL HINTS 1. [. . . ]