Bresser National Geographic 76-700 Mode D'emploi page 14

8. Aligning the finder scope
8.1 Aligning types I and IV (finder scopes)
The finder scope must be adjusted before use; the finder scope and
the telescope's main tube must be aligned parallel to one another.
Insert the eyepiece with the greatest focal length into the zenith mir-
ror ( No. 13a, refracting telescopes only) or directly into the eyepiece
supports (No. 13b, reflecting telescopes only). Point the telescope
at a significant object approximately 300 metres away (e.g. a house
gable, church tower top or building facade) and adjust until the
object appears in the centre of the field of vision (No. 15, A).
Look through the finder scope and align it by turning the three or
six adjustment screws until the object is visible in the middle of the
crosshairs. The image you previously saw through your telescope
lens must be visible exactly in the centre of the finder scope (2)
crosshairs in order to align properly (No. 15, C).
NOTE!
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Some finder scopes have no integrated optical
image reversion. The image in these finder scopes
will be upside down. This is not a fault.
8.2 Aligning, types II and III (LED finder scopes)
The LED finder scope must be adjusted before use; the LED finder
scope and the telescope tube must be aligned parallel to one anoth-
er.
Insert the eyepiece with the greatest focal length into the zenith mir-
ror (No. 13a, refracting telescopes only) or directly into the eyepiece
supports (No. 13b, reflecting telescopes only). Point the telescope
at a significant object approximately 300 metres away (e.g. a house
gable, church tower top or building facade) and adjust until the
object appears in the centre of the field of vision (No. 15 A).
Then turn the LED finder scope (No. 1, 2) on using the On/Off switch
(No. 1b, Z). Select setting 2 for daytime or setting 1 for nighttime.
Look through the LED finder scope and align it by turning the hori-
zontal (No. 1b, X) and vertical (No. 1b, Y) adjustment screws until
you see the red dot in the centre of the image (No. 15, C). The finder
scope and telescope are now aligned.
9. Protection caps:
In order to protect the inside of your telescope from dust and dirt,
the tube opening is protected by a dust-protection cap.
To use the telescope, remove the cap from the opening.
10. Flexible shafts
To ease precise adjustments of the declination and right
ascension axes, flexible shafts are installed in the holding devices of
both axes (No. 14, X).
The long flexible shaft is mounted parallel to the telescope barrel
(No. 1, 14). It is secured in place with a clamping screw in the axis
notch provided.
The short flexible shaft (No. 1, 15) is mounted laterally. It is also
secured in place with a clamping screw in the axis notch
provided.
Your telescope is now ready for use.
14
Part II – Handling
1. Telescope mount:
The following information is important for positioning and tracking
accuracy of your telescope during nighttime observation.
Your telescope is equipped with an equatorial mount, which has two
perpendicular axes on which to rotate your telescope (No. 16, a and
b).
The right ascension axis (RA or axis of sidereal time on the meridian)
(No. 16, b) must be aligned parallel to the Earth's polar axis (No. 26,
c). The coordinates can be found in celestial charts and programs.
Manually operate the right ascension axis via the flexible shaft (No 1,
15) to compensate for the Earth's rotation by turning it in the oppo-
site direction.
An electric tracking accessory, for which the necessary equipment is
already installed, can help you continuously adjust this axis in a con-
trolled way via the flexible shaft.
2. Setup:
A dark place is essential for observations because light of all kinds
(e.g. street lamps) disturb the visible details of the sky. If you leave
a bright room at night, your eyes need approximately 20 minutes to
reach full night adaptation, after which you can begin your observa-
tions.
Don't observe from enclosed areas, and put your telescope in loca-
tion, with the accessories, 30 minutes before beginning observation,
in order to guarantee a temperature balance.
You should also make sure that the telescope is placed on stable
and even ground.
3. Balance:
To avoid damaging sensitive parts of the mount, the two axes must
be balanced before observation.
Balance the right ascension axis by loosening the fixing screws (No.
16, I) and tilting the weight pole into a horizontal position. Adjust the
counterweight (No. 16, H) on the pole until the tube and the weight
remain in this horizontal position. Then retighten the fixing screw (No.
16, I) on the right ascension axis.
Balance the declination axis by loosening the fixing screw (No. 16, D)
on the declination axis. Then loosen the screws on the tube mount
(No. 16, A) and move the tube until it also remains in a horizontal
position. Then retighten the fixing screws.
4. Adjustment:
To set the latitude axis (No. 16, F) (polar height), loosen the fixing
screw (No. 18, X) and adjust the polar height using the adjusting
screw (No. 18, Y).
Adjust the latitude scale to match the local latitude (e.g. Munich, 48°
or Hamburg, 53°).
Don't forget to retighten the fixing screw. Now set the declination
axis (No. 16, C) to 90° by loosening and retightening the screw (No.
16, D). The telescope tube is now pointing to the celestial pole.
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NOTE!
The latitude of your observation site can be found
in maps or on the Internet. A good source of infor-
mation is www.heavens-above.com.