Troubleshooting - Bresser Venus 76/700 AZ Bedienungsanleitung

Formula for calculating magnification:
Focal length of the telescope : focal length of the eyepiece = magnifi-
cation
Beispiele:
Focal length Focal length
telescope
eyepiece
700 mm 20 mm
700 mm 4 mm
6.2. Zenith mirror (refraction telescope only)
The zenith mirror reverses (19) reverses the image (mirror image) and is
therefore used only for celestial observation.
6.3. Barlow lens
A Barlow lens (20) increases magnification three times over.
6.3.1 Assembling and using refracting telescopes
If you use a refracting telescope the Barlow lens should only be inserted
in the zenith mirror (Fig. 12a, X). Remove the eyepiece from the zenith
mirror and replace it with the Barlow lens. Then first insert the eyepiece
with the greatest focal length and then hand tighten the clamping screw
to affix it in place (Fig. 21, Z).
6.3.2 Assembling and using reflecting telescopes
If you use a reflecting telescope please undo the clamping screw on
the eyepiece supports (Fig. 21, X) and remove the eyepiece from those
supports. Then insert the Barlow lens (20) straight in the supports and
hand tighten the clamping screw. Finally first insert the eyepiece with the
greatest focal length in the Barlow lens and then fasten it in place with
the clamping screw (Fig. 21, Z).
6.4 Smartphone holder
Insert the eyepiece into the smartphone holder and tighten the screw
(Fig. 23, X) to the bracket firmly. Then set the smartphone holder with
the eyepiece into the eyepiece connection (6) or the diagonal mirror
(19) (refractor telescopes) and tighten the clamping screws (Fig. 23,
Y) by hand firmly. Now start your smartphone camera app and press
your smartphone on the plate. Make sure that it is properly secured.
The camera should rest just above the eyepiece. Place the smartphone
exactly over the eyepiece, so that the image is exactly centered on
your display. It may be necessary to use the zoom function to fill out the
whole screen of your smartphone. The suction cups must be dry, clean
and free from all kinds of dust and dirt. We assume no responsibility for
dropped and broken smartphones due to incorrect handling.
7. Dismantling
After a hopefully interesting and successful observation, it is recom-
mended that you store the entire telescope in a dry, well aired 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 tube opening and onto the eyepiece connec-
tion. Also, you should stow all the eyepieces and optical accessories into
their corresponding receptacles.
NOTES on cleaning
Clean the lenses (eyepiece and/or lens) with a soft and lint-free cloth
only (e.g. microfibre). Do not apply excess pressure to the cloth so as
to avoid scratching the lenses.
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 - in particular in
situations of high humidity - let the device acclimatize for a short period
of time, so that the residual moisture can dissipate.
Magnification Magnification
with 3x Barlow lens
35X 105X
175X 525X
Part III – Appendix
1. Possible observation targets
In the following, we like to present to you a choice of very
interesting and easy-to-find celestial objects. On the depending pic-
tures at the end of the manual you will see how they will appear in the
eyepiece of your telescope:
The moon (Fig. 24)
The moon is the only natural satellite of the earth.
Diameter: 3,476 km
Distance: 384,000 km (average)
The moon is well-known since thousands of years. He is the second-
brightest celestial object after the sun. Because the moon circles
around the earth, he changes periodically its inclination to the sun;
therefore we see changing phases. The time for one complete lunation
is 29.5 days (709 hours).
Constellation Orion: The great Orion nebula / M 42 (Fig. 25)
Right Ascension: 05h 33' (hours : minutes)
Declination: -05° 25' (Degrees : minutes)
Though it is 1,600 light years away, the Orion nebula (M 42) is the
brightest nebula object at the sky – visible even with naked eyes and
a worthwhile object for telescopes of all kinds and sizes. It consists of
a gigantic cloud of hydrogen gas with a diameter of hundreds of light
years, taking a field on the sky of 10°.
Constellation Lyra: The Ring Nebula / M 57 (Fig. 26)
Right Ascension: 18h 52'
Declination: +32° 58'
Distance: 4,100 light years
The famous Ring Nebula is often called the prototype of planetary
nebulae; he belongs to the northern hemisphere summer sky's pieces
of splendour. Recent investigations have shown that he is a ring of
light-emitting matter that surrounds its central star (only visible in bigger
telescopes). If one could look onto its top, he would see a structure like
the Dumbbell Nebular / M 27
Constellation Vulpecula (little fox):
The Dumbbell Nebula / M 27 (Fig. 27)
Right Ascension: 19h 59'
Declination: +22° 43'
Distance: 1,250 light years
The Dumbbell Nebula / M 27 was the first planetary nebula ever
found. On July 12th, 1764, Charles Messier discovered this new and
fascinating class of objects. We can see it directly from its equatorial
pane. If it could be viewed from top, we would appear like the Ring
Nebula / M 57. This Object can even be viewed at average weather
conditions at low magnifications.

2. Troubleshooting

Mistakes:
No picture
Blurred picture
No focus possible
Bad picture
Viewing object visible
in the finder, but not
through the telescope
Despite using star
diagonal prism
the picture is
"crooked"
- 12 -
Help:
Remove dust protection cap and
sunbathe-shield from the objective
opening.
Adjust focus using focus ring
Wait for temperature to balance out
Never observe through a glass surface
Adjust finder (See Part II-4)
The star diagonal prism
should be vertical in
the eyepiece connection