User manual SKY-WATCHER EQ6

[. . . ] HEQ5/EQ6 MOUNT SLOW GUIDE 2 FAST 1 3 5 4 7 6 SET GO SLOW GUIDE 2 FAST 1 3 5 4 7 6 SET GO 130405V1 A B C D HEQ5 E F G REFRACTOR HI J 16 15 L 14 13 12 11 10 9 8 SLOW GUIDE K 1 2 3 4 5 N M A 2 FAST B 6 1 3 5 4 7 6 C SET GO D E F G EQ6 7 H 16 HEQ5 A. Mounting Plate 13 12 11 10 SLOW GUIDE 1 2 3 4 5 NM L 2 FAST 1 3 9 5 4 7 6 6 7 SET GO 8 A B C D HEQ5 E F G REFRACTOR HI J 16 15 L 14 13 12 11 10 9 8 SLOW GUIDE K 1 2 3 4 5 N M A 2 FAST B 6 1 3 5 4 7 6 C SET GO D E F G EQ6 7 H 16 HEQ5 A. Mounting Plate 13 12 11 10 SLOW GUIDE 1 2 3 4 5 NM L 2 FAST 1 3 9 5 4 7 6 6 7 SET GO 8 E REFLECTOR FG HI HEQ5 J D K L C BA 16 15 E FG 14 13 12 11 10 9 SLOW GUIDE EQ6 1 2 3 4 5 D C H I J K L A 2 FAST 1 3 5 4 7 6 B 6 7 16 15 14 SET GO HEQ5 A. Eyepiece Focus Tube Focus Knob Dust Cap/Mask (Remove before viewing) Finderscope Finderscope Bracket Alignment Screw Tension Adjustment Screw Piggyback Bracket Tube Rings Telescope Main Body Primary Mirror Location A. [. . . ] Very long optical tubes need to be mounted higher or you will end up crouching or lying on the ground when looking at objects near the zenith. On the other hand, a short optical tube can be mounted lower so that there is less movement due to vibration sources, such as wind. This is something that should be decided before going through the effort of polar aligning the mount. Fig. i-3 a. b. Telescope pointing at the Zenith 16 Choosing the appropriate eyepiece Calculating the magnification (power) The magnification produced by a telescope is determined by the focal length of the eyepiece that is used with it. To determine a magnification for your telescope, divide its focal length by the focal length of the eyepieces you are going to use. For example, a 10mm focal length eyepiece will give 80X magnification with an 800mm focal length telescope. Focal length of the telescope magnification = Focal length of the eyepiece = 800mm 10mm = 80X When you are looking at astronomical objects, you are looking through a column of air that reaches to the edge of space and that column seldom stays still. Similarly, when viewing over land you are often looking through heat waves radiating from the ground, house, buildings, etc. Your telescope may be able to give very high magnification but what you end up magnifying is all the turbulence between the telescope and the subject. A good rule of thumb is that the usable magnification of a telescope is about 2X per mm of aperture under good conditions. Calculating the field of view The size of the view that you see through your telescope is called the true (or actual) field of view and it is determined by the design of the eyepiece. Every eyepiece has a value, called the apparent field of view, which is supplied by the manufacturer. Field of view is usually measured in degrees and/or arc-minutes (there are 60 arc-minutes in a degree). The true field of view produced by your telescope is calculated by dividing the eyepiece's apparent field of view by the magnification that you previously calculated for the combination. Using the figures in the previous magnification example, if your 10mm eyepiece has an apparent field of view of 52 degrees, then the true field of view is 0. 65 degrees or 39 arc-minutes. Apparent Field of View True Field of View = Magnification 52° 80X = = 0. 65° To put this in perspective, the moon is about 0. 5° or 30 arc-minutes in diameter, so this combination would be fine for viewing the whole moon with a little room to spare. Remember, too much magnification and too small a field of view can make it very hard to find things. It is usually best to start at a lower magnification with its wider field and then increase the magnification when you have found what you are looking for. Calculating the exit pupil The Exit Pupil is the diameter (in mm) of the narrowest point of the cone of light leaving your telescope. Knowing this value for a telescope-eyepiece combination tells you whether your eye is receiving all of the light that your primary lens or mirror is providing. This value, varies a bit from person to person, is less until your eyes become fully dark adapted and decreases as you get older. To determine an exit pupil, you divide the diameter of the primary of your telescope (in mm) by the magnification. Diameter of Primary mirror in mm Exit Pupil = Magnification For example, a 200mm f/5 telescope with a 40mm eyepiece produces a magnification of 25x and an exit pupil of 8mm. [. . . ] The resulting value is sometimes called the system's "speed". Focuser A device which brings the light rays in a telescope to a precise focus. Common designs include geared (rackand-pinion), gearless (Crayford- style) and helical. C ollimation The process of aligning all the elements of an optical system. Collimation is routinely needed in reflectors, often in Catadioptric systems but seldom in refractors. D eclination Similar to Latitude on the Earth's surface, it is the distance in degrees North or South of the Celestial Equator (the projection of the Earth's Equator onto the Celestial Sphere). [. . . ]