User manual CELESTRON FIRSTSCOPE 76 EQ

[. . . ] Model # 31032 FIRSTSCOPE 76 3" NEWTONIAN EQUATORIAL TELESCOPE Model # 31044 FIRSTSCOPE 114 EQ 4. 5" NEWTONIAN TELESCOPE Model # 31041 FIRSTSCOPE 114 SHORT 4. 5" NEWTONIAN EQUATORIAL TELESCOPE INSTRUCTION MANUAL Equatorial Model 6 Figure 1 2 IDENTIFYING PARTS OF FIGURE 1 1. Front Cell (open part of tube) Secondary Mirror (inside) Star Pointer Finderscope Star Pointer Adjustment Knob (Altitude) Star Pointer Bracket Star Pointer Adjustment Knob (Azimuth) Eyepiece Eyepiece Adapter Focusing Knob 22. INTRODUCTION Thank you for purchasing this Celestron Newtonian Telescope. This telescope is a precision scientific instrument. [. . . ] Remember to always turn the power off after you have found an object. This will extend the life of both the battery and the LED. 7 4. The Celestial - Coordinate System. The celestial-coordinate system is an imaginary projection of the Earth's geographical coordinate system onto the celestial sphere which seems to turn overhead at night. This celestial grid is complete with equator, latitudes, longitudes and poles. The Earth is in constant motion as it rotates on its axis. Actually the celestial-coordinate system is being displaced very slowly with respect to the stars. This is called precession and is caused by gravitational influences from the Sun, Moon and other celestial bodies. All other coordinates are names for the 8 number of hours, minutes and seconds that they lag behind this coordinate after it passes overhead moving westward. Given the celestial coordinate system, it now becomes possible to find celestial objects by translating their celestial coordinates using telescope pointing positions. For this you use setting circles (if you have the Firstscope EQ - equatorial mount models) for R. A. to find celestial coordinates for stellar objects which are given in star charts and reference books. B. Polar Alignment To make tracking the stars easier, rough polar alignment is required. The right ascension (polar) axis should be pointed towards the North Pole (see the illustration below). Your latitude should be set (see 3. A). 9 4. To find astronomical objects, you will now mainly use the right ascension axis as the polar alignment virtually eliminates needed adjustments in the declination axis. To track objects continuously, adjustments will be made with the right ascension cable. When using the telescope, all objects in the sky will slowly drift out of the field of view unless you manually make corrections with the right ascension cable. The above method of polar alignment is adequate for casual observing. More precise methods of polar alignment are available and most astronomy texts or telescope books describe the procedures. If you look at the North Star after this polar alignment procedure, your declination setting circle (#23) should read 90° (the actual is 89. 2°). 6. C. Using the Setting Circles Setting Circles are dials (or gauges) for right ascension and declination that allow you to locate celestial objects easily from their coordinates as listed in a star chart or atlas. 1. The declination setting circle is scaled in degrees and the right ascension setting circle is incremented in minutes. The circles will get you close to your target but not directly on it. Also, the accuracy of your polar alignment will affect how accurate your setting circles read. The declination setting circle is factory set and should not need any adjustment if it reads accurately. The right ascension setting circle (#25) must be aligned. Choose a bright and easy to find star in a star chart and note the coordinates (right ascension and declination). [. . . ] 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. [. . . ]