Manuel d'utilisation / d'entretien du produit 9877 du fabricant Orion
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Astronomical T elescope User Guide OPTICAL VISION LIMITED www.opticalvision.co.uk ® W ARNING!! 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 r eversible eye damage.
O f all the many and varied telescopes av ai lab le for use b y am at eur astronomers and nature watchers, all can be cat egor ised into three typ es: th e r e f r a c t o r , the r e flec t or & the c a t a dioptr ic .
Consequently, an objective lens is a piece of optical equipment that is difficult to manufac - ture and explains why refractors are the most expensive form of telescope, aperture for aperture.
O f all the many and varied telescopes a vailable for u se by the a mateur astronomers, the mountings that sup- port them fall into two types - the alt-azimuth and the equa torial.
Balancing the Telescope: T o eliminate stresses on the EQ equatorial mounts and to ensure smooth, judder-free motion of the tel escope th e inst r ument needs to be balanced about both the declination and polar (right ascension) axis. This is especially im- portant if you propose to use a motor drive for astrophotography at a future date.
Attaching the finderscope: An essential prerequisite for the easy location of objects on both land and in the sky is the corr ect location and al ignment of the finder- scop e that attac hes to the tube of the tele- scope.
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 mir ror to the point at which it forms an image of a distant object.
D e pendi ng on the type of te lescope mount that you possess, there are two ways in which you can move the instr u- ment 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°.
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T he E art h's ea stw ard r otati on c auses stars to apparently rotate around a point in the sky which is a projection of the Earth's axis, called the celestial pole.
12 Polar axis alignment (precise setting) The follow ing process w ill allow tracking without the need for occasional cor rections, an d i s e ss ent ial i f p hoto gra phy us in g a motorised drive is envisioned.
13 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.
14 Using the setting circles (The following applies to telescopes using a single index on the R.A. circle) The easiest way to use setting circles is to off- set 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).
15 W i th t he t el e sco pe as se mb le d, ba la nc ed a n d po l ar -a l i gn e d a s d e s cr i b ed pr e v i o u s l y , yo u a re re ady t o be g in o bs er v a t i o n s .
16 S ince the dawn of mankind there have bee n indepe ndent thinkers who hav e sought to understand the nature of the Universe and our relationship to it.
17 to cover the seven principal stars that delin- eate the figure of Orion. 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 cor r esponds to just over 20 degrees (the symbol for degree is°), while the length of our thumb is about 7°.
18 s peci a l fil ters th at can almost magica lly r emove the orange cast to the sky created by sodium streetlights revealing a dark, star - studded sky beyond.
19 a simple way to avoid camera shake which ruins many a time exposure. So how long should you leave the lens uncov- ered? Under dark skies with ISO 400 film and a 50mm f/2.8 lens you can expose for up to about 20 seconds before the motion of the stars becomes evident as small trails on the film.
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Un point important après l'achat de l'appareil (ou même avant l'achat) est de lire le manuel d'utilisation. Nous devons le faire pour quelques raisons simples:
Si vous n'avez pas encore acheté Orion 9877 c'est un bon moment pour vous familiariser avec les données de base sur le produit. Consulter d'abord les pages initiales du manuel d'utilisation, que vous trouverez ci-dessus. Vous devriez y trouver les données techniques les plus importants du Orion 9877 - de cette manière, vous pouvez vérifier si l'équipement répond à vos besoins. Explorant les pages suivantes du manuel d'utilisation Orion 9877, vous apprendrez toutes les caractéristiques du produit et des informations sur son fonctionnement. Les informations sur le Orion 9877 va certainement vous aider à prendre une décision concernant l'achat.
Dans une situation où vous avez déjà le Orion 9877, mais vous avez pas encore lu le manuel d'utilisation, vous devez le faire pour les raisons décrites ci-dessus,. Vous saurez alors si vous avez correctement utilisé les fonctions disponibles, et si vous avez commis des erreurs qui peuvent réduire la durée de vie du Orion 9877.
Cependant, l'un des rôles les plus importants pour l'utilisateur joués par les manuels d'utilisateur est d'aider à résoudre les problèmes concernant le Orion 9877. Presque toujours, vous y trouverez Troubleshooting, soit les pannes et les défaillances les plus fréquentes de l'apparei Orion 9877 ainsi que les instructions sur la façon de les résoudre. Même si vous ne parvenez pas à résoudre le problème, le manuel d‘utilisation va vous montrer le chemin d'une nouvelle procédure – le contact avec le centre de service à la clientèle ou le service le plus proche.
