® Astronomical Telescope User Guide WARNING!! Never point the telescope directly at or near the Sun at any time. Observing the Sun, even for a fraction of a second, will result in instant and ir reversible eye damage. Please ensure minors ar e supervised by an adult conversant with this real danger when using telescopes or binoculars. OPTICAL VISION LIMITED www.opticalvision.co.
Types of Telescope... f all the many and varied telescopes available for use by amateur astronomers and nature watchers, all can be categorised into three types: the refractor, the reflector & the catadioptric. Each have their relative strengths and weaknesses, but they all have a common function: to gather and focus light from distant objects to produce a bright image that may be magnified. In this respect it is the aperture (i.e.
Consequently, an objective lens is a piece of optical equipment that is difficult to manufacture and explains why refractors are the most expensive form of telescope, aperture for aperture. However, a refractor can deliver exquisite images that are very well corrected and extremly high in contrast, suitable for observing fine lunar and planetary detail, or for separating difficult double stars.
Telescopes & Mounts... The three legs should be attached to the tripod head one by one by the three bolts and wing nuts provided. They should not be overtightened, but just made finger tight. Pay particular attention to the orientation of each leg prior to assembly such that the tripod tray bracket is facing inward. The tripod may now be placed on the ground with the legs splayed enough for the accessory tray to be attached.
screw firmly - the telescope is now balanced about the polar (right ascension) axis. (ii) With the counterweight bar horizontal, ensure that the right ascension clamp is locked and unlock the declination clamp and turn the telescope tube so that it is also horizontal. As before, GENTLY release your grip on the tube and note is there is a tendency for one end to rise in the air. If so, slowly loosen the clamps holding the tube and slowly slide the tube towards the end that rises.
Attaching the finderscope: (iv) Turn the focuser knobs back or forth until the image becomes crisp and sharp. Do not be concerned that the image appears upside down (reflecting telescope) or reversed in a left to right plane (refractor with zenith prism) - this is perfectly natural for an astronomical telescope since there is no 'up' or 'down' in the sky and you will soon get used to it.
The focal length of the telescope is usually given on a label near the eyepiece focuser and is the distance from the main lens or mirror to the point at which it forms an image of a distant object. The magnification of any given telescope/eyepiece combination is given thus: example would enable us to display the whole of the Moon's disc within the eyepiece's field of view.
Using your telescop e ... D epending on the type of telescope mount that you possess, there are two ways in which you can move the instrument in order to locate and track objects in the sky.
The further that one moves across the sky from Polaris, the apparent motion of the stars becomes more evident and their Altitudes and Azimuths will be continually changing. Taking the star labelled ‘AA’ in Fig. 1, at the instant of the observation its Altitude was 60° and its Azimuth bearing was also 60°. It can be seen that Azimuths are measured in degrees from due north (0°) through east (90°), south (180°), west (270°) and back to north (360˚ or 0°).
The equatorial mounting... Setting up and using an equatorial mount he Earth's eastward rotation causes stars to apparently rotate around a point in the sky which is a projection of the Earth's axis, called the celestial pole. A star's path through the sky from an earthbound observer's viewpoint is therefore an arc of this rotation; it rises in the east towards its highest altitude (on the local meridian - directly south) and then sets in the west. It does not travel in a line parallel to the horizon.
North Celestial Pole (near Polaris) west on the polar axis only as shown in figure 2a) so that the star is impelled to move from one side of the eyepiece field to the other. It will help if you arrange this line of motion to bisect the eyepiece field (as in figure 2b ). Declination Circle Polar axis Right Ascension Circle This procedure can be made easier if a reticle is placed at the eyepiece focus and aligned to indicate this motion, rather than having to remember it in the mind's eye.
Once this line of axial movement has been established, set the star at the edge of the field and allow it to drift across via its own motion. If the star drifts upwards from this line (figure 5a ), then the north end of the polar axis needs to be raised. If the star drifts below this line (figure 5b ), the north end of the polar axis needs to be lowered. This altitude adjustment is shown in figure 1a .
Using the setting circles Figure 6 (The following applies to telescopes using a single index on the R.A. circle) The easiest way to use setting circles is to offset from a known position. Set the telescope on an object whose position is known (i.e. a bright star in a recognisable constellation such as listed in the appendix). Unclamp and turn the R.A. circle so that the its pointer indexes the observed object's positional hour and minute. E.g. In figure 6 , the R.A.
Tips on observing with your telescope... ith the telescope assembled, balanced and polar-aligned as described previously, you are ready to begin observations. Decide on an easy to find object such as the Moon, if visible, or a bright star to become accustomed to the functions and operations of the telescope. For the best results during observations, follow the suggestions given as follows:- object in the field of view will begin to slowly move across the eyepiece field.
Get to know the sky... ince the dawn of mankind there have been independent thinkers who have sought to understand the nature of the Universe and our relationship to it. It is perhaps the city or suburban observer who feels the call of the cosmos most intensely when he or she experiences the majesty of the night sky from a truly rural location for the very first time.
to cover the seven principal stars that delineate the figure of Orion. A further hand span to the upper left brings you to the celestial twins of Gemini, Castor and Pollux. If we wish to be a little bolder we can relate the span of our outstretched hand to actual angular measure. It so happens that the span of our hand corresponds to just over 20 degrees (the symbol for degree is°), while the length of our thumb is about 7°.
special filters that can almost magically remove the orange cast to the sky created by sodium streetlights revealing a dark, starstudded sky beyond. These filters are not cheap – you can spend £100 quite easily for two for a pair of binoculars – but to the telescope user they are almost mandatory for any serious work concerned with hunting for galaxies and faint nebulae. (or 'B' setting) setting, a standard 50mm lens, a fast colour (or B/W, it's up to you) film, tripod and cable release.
a simple way to avoid camera shake which ruins many a time exposure. make sure that the technician knows that your subject matter is astronomical since it is very frustrating to return to pick up your hardearned snaps only to be told that the roll was unexposed - they're just not used to seeing tiny white dots! Just tell them to print all frames regardless.
