Omegon EQ-1 Mode D'emploi page 70

Minimum, optimal and maximum magnifications
Every telescope has a minimum and a maximum magnification. You should not use magnifications outside this
range for optical reasons, although it would be technically feasible to do so. There is also a magnification where
you are employing the full resolving power of your telescope.
In order to calculate this magnification, you need to determine the following: divide the focal length of your
telescope by its lens aperture, e.g. 900mm/114mm. This gives the aperture ratio, or f-number, of your telescope.
For a telescope with specifications 114/900mm, this would be f/7.8.
Minimum magnification
The eyepiece focal length for the minimum magnification, in mm = 5 x aperture ratio
Optimal magnification
The eyepiece focal length for the ideal magnification = aperture ratio in mm
Maximum magnification
The eyepiece focal length for the maximum magnification, in mm = aperture ratio / 2
Eyepiece and focuser
The eyepiece is always inserted into the focuser. Tightening the locking screw prevents the eyepiece from
falling out. The focuser can be moved inwards or outwards with the focus wheel. This brings celestial objects
into a sharp focus for your eye.
1. Find the object with the telescope and centre on it.
2. While looking through the eyepiece in the focuser, slowly turn the focus wheel until the object comes into
the sharpest focus possible.
Tip: A star must appear small and absolutely punctiform, only then is it in sharp focus. If the star appears larger,
2-dimensional or has a black circle in the centre, it has not yet been focused.
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