Bresser JUNIOR 70/900 NG Mode D'emploi page 23

1*
9. Finding stars
In the beginning, you will certainly find it dif-
ficult to orient yourself in the sky, since stars
and constellations 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 num-
ber of the more familiar constellations and star
clusters, which are visible throughout the year.
The position of the stars is, of course, depen-
dent 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, opera-
te the flexible shaft (17) of the counterweight
axis, und your telescope will follow the appa-
rent 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 te-
lescope.
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
properly orientated side-to-side (no mirror-
image, in other words), you must use the in-
verting 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
GB
Magnification
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