User manual SKY-WATCHER HEQ5

[. . . ] 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. Dust Cap/Mask (Remove before Viewing) I J K EQ6 A. Dust Cap/Mask (Remove before Viewing) 15 14 B. 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. [. . . ] It is very important to move the tube back to the Dec-balanced position before observing other sky areas. Something which can be a problem is that the optical tube often rotates so that the eyepiece, finderscope and the focussing knobs are in less convenient positions. The diagonal can be rotated to adjust the eyepiece. However, to adjust the positions of the finderscope and focussing knobs, loosen the tube rings holding the optical tube and gently rotate it. Do this when you are going to view an area for while, but it is inconvenient to do every time you briefly go to a new area. Finally, there are a few things to consider to ensure that you are comfortable during the viewing session. First is setting the height of the mount above the ground by adjusting the tripod legs. You must consider the height that you want your eyepiece to be, and if possible plan on sitting on a comfortable chair or stool. 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. [. . . ] 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). The degrees can be subdivided into minutes and seconds. Dew Cap A tube extending forward from the front lens of a telescope. [. . . ]