User manual CELESTRON FIRSTSCOPE 21086 INSTRUCTION MANUAL

[. . . ] FIRSTSCOPE 60 EQ REFRACTORS MODELS #21067 FIRSTSCOPE 70 EQ REFRACTOR MODEL #21076 FIRSTSCOPE 80 EQ REFRACTORS MODELS #21086 INSTRUCTION MANUAL FIRSTSCOPE EQ REFRACTORS FIGURE 1 3 LIST OF PARTS: FIRSTSCOPE EQ REFRACTORS 1. Telescope Objective (inside) Diagonal Star Pointer Finderscope Star Pointer adjustment knob (Altitude) Star Pointer bracket Star Pointer adjustment knob (Azimuth) Eyepiece Tripod leg adjusting screw Focusing knob Rack and pinion focuser Telescope optical tube Tube mounting plate and bolts Declination cable holder Safety washer for counterweight Tripod head (part of mount) Polar axis knob Latitude scale Declination cable 19. Tripod tray bracket (Collapsible leg brace on some models) Tripod leg Finderscope bracket mounting screws Declination tightening knob Right ascension setting circle Right ascension tightening knob Declination setting circle Front lens cover Right ascension cable holder Horizontal adjustment knob Counterweight shaft Counterweight Right ascension cable Tripod accessory tray & hardware Equatorial mount Tripod leg mounting hardware Tripod leg tips Optical Tube with Mounting Rings for 70mm/80mm Telescopes 4 INTRODUCTION Congratulations on your purchase of a Celestron equatorial refractor telescope. This telescope is a precision scientific instrument that will allow you to enjoy viewing numerous objects in the night sky -- planets, nebulae, star clusters, galaxies and more. [. . . ] RA coordinates are marked off in units of time eastward from an arbitrary point on the celestial equator, in the constellation Pisces. The prime RA coordinate which passes through this point is designated "O hours O minutes O seconds. " We call this reference point the vernal equinox where it crosses the celestial equator. All other coordinates are names for the number of hours, minutes and seconds that they lag behind the prime coordinate after it passes overhead, moving westward. 10 Using the celestial coordinate system, it becomes possible to find celestial objects by translating their celestial coordinates, using telescope pointing positions. To do this, you use your RA and DEC setting circles to find celestial coordinates for stellar objects. These coordinates are given in star charts and reference books. 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 previous section on "Setting Latitude" ). 11 Figure 3A For the most part, to find astronomical objects you'll be using the right ascension axis, as polar alignment virtually eliminates the need to adjust the declination axis. To track objects continuously, adjustments must be made with the right ascension cable, otherwise the rotation of the earth will cause the object you're viewing to drift out of your field of view. The method of polar alignment described above is adequate for casual observing. More precise methods of polar alignment are available, and most astronomy or telescope textbooks describe these procedures. Look at the North Star after doing the polar alignment procedure given here - your declination setting circle should read 90º. SETTING CIRCLES The setting circles are dials, or gauges, for right ascension and declination that allow you to locate a celestial object easily using its coordinates, as listed in a star chart or atlas. The declination setting circle is scaled in degrees and the right ascension setting circle is laid out in increments of minutes. The setting circles will assist you to get close to your target, but not directly on it. It's important to note that the accuracy of your polar alignment will affect the accuracy of your setting circles readings. The declination setting circle is set at the factory and won't require adjustment if it reads accurately. The right ascension setting circle must be aligned. Choose a bright and easy to find star on a star chart, and note its right ascension and declination coordinates. Find the star and center it first with the Star Pointer finderscope, then in the telescope. Rotate the right ascension circle to match the coordinates of the star with the indicator mark. 12 The right ascension setting circle does not move as the telescope moves in right ascension, and thus it must be aligned each time you want to use it to find a new object. However, you don't need to use a bright star each time. Instead, you can use the object you're observing at the time. [. . . ] 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. [. . . ]