Bresser Junior 70/900 EL Instrucciones De Uso página 23

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9. Finding stars
In the beginning, you will certainly find it difficult
to orient yourself in the sky, since stars and con-
stellations are always moving, and their position
in the sky varies according to the season, date,
and time.
The North Star is an exception to this. If you
were to imagine the polar axis of the Earth ex-
tending out into space, it would approximately
hit the North Star. The so-called north celestial
pole is the starting point for all star charts.
On the drawing (Figure 18), you see a number of
the more familiar constellations and star clus-
ters, which are visible throughout the year. The
position of the stars is, of course, dependent on
date and time.
If you have fixed your telescope on one of the-
se stars, you will notice that within a short time
it disappears from the eyepiece field of vision.
In order to compensate for this effect, operate
the flexible shaft (17) of the counterweight axis,
und your telescope will follow the apparent path
of this star.
10. Accessories
Three eyepieces (18) (Figure 2) come with your
telescope. By switching the eyepieces, you can
control the magnification of your telescope.
Note:
Focal width of the :
telescope tube
Let's calculate:
The zenith Mirror (19) (Figure 2) produces an
image reversal (mirror-image) and is only used
for astronomical observation.
In order to see an image that is upright and pro-
perly orientated side-to-side (no mirror-image,
in other words), you must use the inverting lens
that came with your telescope.
Loosen the clamping screw (39) and take the
zenith mirror out of the eyepiece holder (6)
(Figure 1). Then set the inverting lens (20) (Fi-
gure 2) straight into the eyepiece holder and
retighten the clamping screws with your hand.
Then, place the eyepiece (e.g. f = 20 mm) into
the opening of the inverting lens and tighten the
clamping screw there.
Focal width of the =
eyepiece
900 mm : 20 mm = 45x
900 mm : 12 mm = 75x
900 mm : 4 mm = 225x
EN
Magnification
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