Bresser NATIONAL GEOGRAPHIC 9071000 Mode D'emploi page 14

Once you make this alignment, do not move or adjust the telescope, or it will
become misaligned. The telescope is now correctly aligned. This procedure is
essential so you can track celestial objects.
6. Tracking and Observation Positioning
Tilt the telescope 90° using the declination axis (No. 15, C). Then turn the tel-
escope 180° to the right or left, until the objective lens points skyward.
Tighten the clamping screws on the two flexible shafts (No. 13, X and Y) so that
you can track stars using these flexible shafts. Manual use of the flexible shaft
along the right ascension axis (No. 15, D) compensates for the Earth's rotation,
so that objects always remain visible in the eyepiece.
If you want to track a different celestial object than the one you're currently
focused on, undo the clamping screws on the flexible shafts (No. 13, X and
Y), reposition the telescope, and then retighten the clamping screws. You can
then use the flexible shafts to do fine adjustments to the telescope's position.
HINT
i
The latitude of your observation site can be found in maps
or on the Internet. A good source of information is www.
heavens-above.com. After checking "anonymous user" >
"select" you may choose your country and city.
7. Viewfinder
The telescope is now roughly aligned and adjusted.
In order to obtain a comfortable observation position, you should loosen the
screws on the tube ring (No. 1, 8), so that you can rotate the telescope tube.
Bring the eyepiece and the viewfinder into a position that makes it comfortable
for you to look through both.
Fine alignment is done using the viewfinder scope. Look through the viewfinder
scope and centre Polaris (No. 16) in the middle of the crosshairs (No. 17).
For fine adjustments, use the flexible shafts along the right ascension axis (No.
15, D) and the declination axis (No. 15, E).
8. Observation
After you have located the pole star in the viewfinder scope, if you look through
the eyepiece, the pole star will be visible.
If necessary, you can use the flexible shafts to align the star more exactly, just
as you can adjust the image sharpness by using the focus wheel (No. 15, F).
Furthermore, you can now, by changing the eyepiece, increase the magnifica-
tion. Note that the magnification of the stars can hardly be seen.
HINT
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Eyepieces enlarge the picture of the telescope's prime
focus. The less the eyepiece's focal lengths is, the stronger
the magnification is. So various eyepieces are needed to
reach different magnifications. Begin every observation with
a low magnification (20 mm eyepiece), and increase the
magnification until you reach the desired picture size.
9. Find a Star
Initially it will be difficult for you to find your bearings in the firmament, since
the stars and the constellations are always moving, and according to the
season, date and time, their position in the heavens will change. The pole star
(Polaris) is the exception. It is a fixed star and the starting point for all star
maps.
When you first start observing, you should look at some well-known constella-
tions and star groups that are visible all year round. Remember that the position
of even constantly visible constellations shifts throughout the year.
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If you have aligned your telescope accurately to observe one of these stars, you
will find that it vanishes from your field of view after a few minutes. To even out
this effect, you must turn the flexible handle (No. 15, D) along the declination
axis and your telescope will follow the trajectory of this star.
10. Accessories
Your telescope comes with three eyepieces (No. 2, 18).
By interchanging the eyepieces, you can alter the magnification of your tel-
escope.
Formula for calculating magnification:
Focal length (Telescope) ÷ Focal length (Eyepiece) = Magnification
Examples:
Focal length Focal length
of telescope of eyepiece
900 mm 20 mm
900 mm 12 mm
900 mm 4 mm
The diagonal mirror (No. 2, 19) causes the image you view to be horizon-
tally reversed. You should use the diagonal mirror whenever making terrestrial
observations.
In order to see an upright and sidecorrect picture, you may use the erecting
lens. Loosen the screw (No. 8, X) and remove the diagonal mirror from the
eyepiece connection tube (No. 1, 6). Now put the erecting lens (No. 2, 20) in
place and retighten the screw. Finally, put an eyepiece in place and tighten the
screw (No. 9, X).
11. Dismantling
After your interesting and successful observation, it is recommended that you
store the entire telescope in a dry, well-ventilated area. On some telescopes,
the tripod and mount can easily be separated. The adjustments to the mount
will remain intact.
Don't forget to put the dust protection caps onto the barrel opening and the
eyepiece connection. Also, you should stow all the eyepieces and optical acces-
sories into their corresponding receptacles.
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HINT
The erecting lens is not recommended for astronomical
observations. Only use the diagonal mirror here.
To observe landscapes, you may use the erecting lens.
Notes on Cleaning
Clean the eyepieces and lenses only with a soft, lint-free cloth, like a microfibre
cloth. To avoid scratching the lenses, use only gentle pressure with the clean-
ing cloth.
To remove more stubborn dirt, moisten the cleaning cloth with an eyeglass-
cleaning solution, and wipe the lenses gently.
Protect the device from dust and moisture. After use, particularly in high humid-
ity, let the device acclimatize for a short period of time, so that the residual
moisture can dissipate before storing. Remove the dust protection cap and
store it in the included bag during use.
Magnification
Magnification
with 1.5 erecting lens
45X 67X
75X 112X
225X 337X