BRESSER 8845001 Refractor Telescope Instruction Manual
- June 9, 2024
- BRESSER
Table of Contents
- BRESSER 8845001 Refractor Telescope
- UKCA Declaration of Conformity
- Warranty & Service
- Your telescope has the following parts
- Assembly
- Using the Telescope
- Troubleshooting
- Technical data
- Possible objects for observation:
- Telescope ABC’s
- References
- Read User Manual Online (PDF format)
- Download This Manual (PDF format)
BRESSER 8845001 Refractor Telescope
RISK to your child!
Never look through this device directly at or near the sun. There is a risk of
BL-INDING YOURSELF!
Children should only use this device under su-pervision. Keep packaging
materials (plastic bags, rubber bands, etc.) away from children. There is a
risk of SUFFOCATION!
Fire/Burning RISK!
Never subject the device – especially the lenses – to direct sunlight. Light
ray con-centration can cause fires and/or burns.
RISK of material damage!
Never take the device apart. Please con- sult your dealer if there are any
defects.
The dealer will contact our service centre and send the device in for repair
if needed.
Do not subject the device to temperatures ex-ceeding 60 C.
TIPS on cleaning
Clean the lens (objective and eyepi-ece) only with the cloth supplied or some other soft lint-free cloth (e.g. micro-fibre). Do not use excessive pressure – this may scratch the lens.
Dampen the cleaning cloth with a spectacle cleaning fluid and use it on very
dirty lenses.
Protect the device against dirt and dust. Leave it to dry properly after use
at room temperature. Then put the dust caps on and store the device in the
case provided.
RESPECT privacy!
This device is meant for private use. Respect others‘ privacy – do not use the device to look into other people‘s homes, for example.
DISPOSAL
Dispose of the packaging material/s as legally required. Consult the local
autho-rity on the matter if necessary.
EC Declaration of Conformity
Bresser GmbH has issued a “Declaration of Conformity” in accordance with
applicable guidelines and corresponding standards. The full text of the EU
declaration of conformity is available at the following internet address:
www.bresser.de/download/8845001/
CE/8845001_CE.pdf
UKCA Declaration of Conformity
Bresser GmbH has issued a „Declara-tion of Conformity“ in accordance with
applicable guidelines and corresponding standards. The full text of the UKCA
declaration of conformity is available at the following internet address:
www.bresser.de/download/8845001/
UKCA/8845001_UKCA.pdf
Bresser UK Ltd. • Suite 3G, Eden House, Enterpri-se Way, Edenbridge, Kent TN8
6HF, Great Britain
Warranty & Service
The regular guarantee period is 5 years and be-gins on the day of purchase. You can consult the full guarantee terms and details of our ser-vices at www.bresser.de/warranty_terms.
Your telescope has the following parts
-
Telescope tube
-
Finder
-
Adjusting crews for finder
-
Tube opening
-
Objective lens
-
Eyepiece holder
-
Focus adjustment knob
-
Tube holder
-
Tripod head (with pole elevator cradle and mount)
-
Accessory tray
-
Locking clips (on tripod)
-
Mounting bracket for the tray (on division bar)
-
Tripod legs
-
Flexible shaft (long)
-
Flexible shaft (short)
-
Tripod leg brace
-
Latitude control rod
-
3 Eyepices (Ø 31.7 mm or 11/4”):
f = 20 mm, f = 12 mm, f = 4mm 19 Zenith mirror -
Inverting lens 1.5x
Parts of the Eyepiece holder (Figure 8) -
Clamping screw
-
a Lens Cover
Parts of the Zenith Mirror (Figure 9) -
Clamping screw
Parts of the Finder (Figure 10) -
Front lens mount (objective lens)
23a Objective lens counter-ring -
Finder holder
Parts of the Telescope Tube (Figure 12) -
Lens Cover
-
Axel with flexible shaft (Figure 13)
-
27 Clamping screw for the flexible shaft
Pole elevator cradle (Figure 14) -
Clamping screw for pole elevator cradle
-
Latitude control rod
-
Tilt plate
Parts of the Mount (Figure 15)
- 26 Flexible shaft (for counterweight shaft, for tracking)
- 27 Flexible shaft (for declination shaft)
- 31 Vertical clamp
- 31a Declination shaft
- 32 Dovetail adapter
- 33 Horizontal clamp
Assembly
2. General Information regarding Assembly, Positioning
Before beginning with the assembly, choose a suitable position for your
telescope.
It will help if you assemble this apparatus at a spot from where you have a
clear view of the sky, a sturdy surface beneath you, and enough space.
Important: Tighten screws only as much as you can by hand – do not „over-
tighten“ the screws.
Tripod
Take the three-legged tripod and set it vertically on the floor with the feet
pointing downwards. Now take two of the tripod legs (13) and pull these legs
carefully out away from each other, until they have reached their fully opened
posi-tion. During this time, the entire weight of the
tripod rests on one leg. Finally, set the tripod down on all legs, so that it
stands straight.
Loosen the three locking clips (11) (Figure 1 + 4) on the tripod legs, pull
each individual tripod leg out until it has reached the desired length (see
figure 4), close up the locking clips and set the tripod down on a sturdy,
even surface.
TIP:
A small water level on the accessory tray can help you position your tripod
horizontally.
Mounting the tray:
The accessory tray (10) (Figure 1 + 3) must be positioned with its flat side
down in the middle of the tripod leg brace (16) (Figure 1), and then must be
mounted by turning it 60° in a clockwi-se direction (Figure 5).
The three projections on the tray plate must match up to the mounting brackets on the divisi-on bars (12) (Figures 1 + 3) and must snap into place. If necessary, you may push the tripod leg brace downwards a little.
Tube
In order to mount the telescope tube (1) (Fig. 1), loosen the locking screw on
the tube clamp (8) (Fig. 6) and open up the clamp.
Set the tube in the middle of the holder and snap the clamp shut again. Please
screw the locking screw on the holder tightly, using your hand only.
Now set the tube (and holder) onto the mount with the objective opening in the
direction marked (N-marking on the tripod head, north point and telescope
figure on the mount). Then fasten the tube holder with the clamping screw of
the dovetail adapter on the mount head (Fi-gure 7).
Inserting the Eyepiece
Three eyepieces (18) (Figure 2) and one zenith mirror (19) (Figure 2) come
with your tele-scope. With the eyepieces, you can control the magnification of
your telescope.
Before installing the eyepieces and the zenith mirror, take the lens cap (21a)
out of the eyepi-ece holder (6) (Figure 1). Loosen the clamping screws (21) on
the eyepiece holder and insert the zenith mirror. Then screw the clamp screws
(21) back on.
Finally, in the same way (by opening and clo-sing the clamp screws) secure the 20-mm eye-piece in the zenith mirror.
Be sure that the entrance of the eyepiece (the end you look into) is facing straight upwards. This will make observation easier. Alternatively, loosen the clamp screws (21) on the eyepiece holder and turn the zenith mirror into this po-sition.
Mounting and Adjusting the Finder
Slide the foot of the finder holder (24) comple-tely into the finder holder
base on the telescope tube (Figure 10). The finder holder will snap into
place. Be sure that the objective lens on the fin-der is pointing in the
direction of the front tube opening.
On the finder holder, there are adjusting screws for the finder (3) (Figure
1): two clamp screws (black) and one spring-loaded counter screw (silver). The
clamp screws (black) are to be screwed (equally as far) in so that you can
feel some resistance; the finderscope is then secu-re.
Before beginning an observation, it is absolutely necessary that you align the
finderscope – the finderscope and the main telescope must point to exactly the
same position. Here is the pro-cess for alignment:
Take the 20-mm eyepiece, set it into the zenith mirror and aim the main
telescope at an easy to find, clearly defined earthbound object (Fi-gure 11,
e.g. church steeple, gable of a house). The object should be at least 200-300
meters away. Hone in on the object so that it is exactly in the middle of the
field of vision when you look through the eyepiece.
The image reproduced will be upright, but ro-tated around its vertical axis
(you will see a mirror-image). In the finder, however, the repro-duced image
will be upright and its sides will not be reversed, as above. Now turn one of
the two clamp screws (right/left) of the finderscope while looking
continuously through the finder. Continue to turn until the finder’s
crosshairs are exactly over the position that corresponds to what you see when
you look through the eyepie-ce of the main telescope.
Focusing the finderscope:
Turn the front lens mount (23) one to two rota-tions to the left. Now you can
adjust the coun-ter-ring (23a) by itself.
Look through the finder and focus on a far-away object. Turn the front lens
mount (23) in one direction or another until the object appears in focus. Now
screw the counter-ring (23a) in the direction of the lens mount.
Lens Covers
In order to protect the interior of your telescope from dust and dirt, the
opening of the tube is protected by a lens cover. There is also a lens cover
(21) on the eyepiece holder (6) (Figure 1).
For observing, take the caps off the openings.
Flexible shafts In order to facilitate the exact fine adjustment of the declination- and right ascension shafts, the flexible shafts have been placed on the holders of both these shafts, in the places designed for that purpose.
The long flexible shaft (14) (Figure 1) is moun-ted parallel to the telescope
tube. It is secured with a clamp screw (16, 17) on the designated indentation
on the shaft.
The short flexible shaft (15) (Figure 1) is moun-ted sideways. It is secured
with a clamp screw (16, 17) on the designated indentation on the shaft. Your
telescope is now ready for use.
Using the Telescope
Operation –Mounting
Your telescope comes with a mount that gives you two possibilities for
observation.
A: Azimuthal = ideal for viewing objects on the Earth (terrestrial
observation)
B: Parallactic = ideal for viewing objects in the sky (astronomical
observation)
Regarding A:
In azimuthal mode, the telescope swings hori-zontally and vertically. Loosen
the pole elevator clamp screw (28) and lower the tilt plate (30) until it is
horizontal (in other words, until it stops). Screw the pole ele-vator clamp
screw back on.
Loosen the vertical clamp (31) and set the tube in a horizontal position.
Screw the clamp back on.
By turning both flexible shafts (14, 15) (Figure 1), the telescope can be
moved horizontally and vertically.
Regarding B: Kapitel (3–11).
Set-Up (at night)
A dark location is very important for many ob-servations, as bothersome lights
(lamps, lan-terns) can have quite a negative effect on the detail and clarity
of the telescope image.
If you leave a bright room at night to go outside, your eyes need time to
adjust to the darkness.
After approx. 20 minutes, you can begin with the astronomical observation.
Do not observe from closed spaces, and set up your telescope with the
accessories approx. 30 minutes before beginning observation; this will ensure
that the temperatures inside the tube have adjusted.
In addition, you should be careful to set your te-lescope on a level, stable
surface.
First time Set-up
Loosen the pole elevator clamp screw (28) and set the tilt plate (32) roughly
to the latitude of your location, according to the scale of the lati-tude
control rod (29) – in Germany, this is about 50°. Point the part of the tripod
with the North-marking (N) in a northerly direction. The upper side of the
tilt plate will also be pointing north. The latitude control rod will be
pointing south.
Positioning of Geographical Latitude
From a street map, an atlas, or the Internet, find out your location’s angle
of latitude. Germany lies between 54° (Flensburg) and 48° (Mu-nich) north
geographical latitude. Now loosen the pole elevator clamp screw (28) and tilt
the tilt plate (32) until the number on the latitude control rod (29) that is
next to the clamp is the same number as your location‘s angle of latitu-de
(e.g. 51°).
TIP:
The angle of latitude can always be found in an atlas on the right side, or on
the left side of a map. You can get more informa-tion at your city hall, your
land registry of-fice, or on the Internet: for instance, at www.heavens-
above.com. There, under “An- onymous user > Select,” you can choose your
country; the relevant information will then come up.
Final orientation
Turn the declination shaft (8) as well as the te-lescope holder upwards 90°
(white arrow mar-kings at the front of the mount will be across from each
other). Set the tube the right way around (see telescope illustration and
north ar-row) in the holder and tighten the clamp screw. The eyepiece of the
telescope is now pointing at the ground; the objective lens is pointing at the
North Star. Loosen first the clamp of the latitude control rod and then the
clamp of the declination shaft, and bring the North Star into the middle of
the eyepiece field of vision. Finally, retighten the clamp. From this point
onward, the tripod may not be moved or ad-justed because the orientation will
be lost.
The telescope is now properly oriented. This procedure is necessary for
tracking celestial bodies.
Tracking- and/or Observation Position
Loosen the vertical clamp (8) and tilt the tele-scope tube 90° downwards.
Loosen the hori-zontal clamp (33) and turn the telescope 180° to the right or
left, until the objective lens is pointing in the direction of the sky.
Retighten all clamps so that you can track with the flexible shaft.
The manual operation of the counterweight axis (right ascension axis, R.A.
axis) via the flexible shaft (26) allows for the rotation of the Earth in such
a way that the positioned object always stays in the eyepiece field of vision.
If you would like to switch to another object, loosen the clamps, swing with
the tube in the proposed direction and retighten the clamps. The fine
adjustment is then performed with the flexible shafts (14, 15) (Figures 1).
Finder
Your telescope is now roughly aligned and set up.
In order to obtain a comfortable observation position, carefully loosen the
screw on the tube clamp (8) (Figure 1) so that you can turn the telescope
tube. Bring the eyepiece and the fin-derscope into a position from which you
can observe comfortably.
The fine adjustment happens with the help of the finderscope (2). Look through
the finder and try to hone in on, for instance, the North Star (Figure 16),
positioning it in the middle of the finder‘s crosshairs (Figure 17). For the
exact adjustment, the shaft of the counterweight axis (26) as well as the
shaft of the declination axis
(27) will be helpful.
Observation
After you have located the North Star in the fin-der, you will be able to
recognize the North Star when you look through the eyepiece of the tele-scope.
If needed, you can angle the telescope even more exactly toward the star (with
the help of the flexible shafts), or you can adjust the fo-cus with the focus
knob (7) (Figure 1).
Additionally, you can now switch to a higher magnification by changing the
eyepiece (to a smaller focal width). Please be aware that the magnification of
the stars is barely perceptible.
TIP:
Eyepieces are lens systems designed for your eye. In an eyepiece, the clear
image that is gene-rated in the focal point of a lens is captured (in other
words, made visible) and magnified still more. Eyepieces with various focal
widths are necessary in order to achieve various degrees of magnification.
Begin each observation with an eyepiece with a low magnification (= large
focal width, e.g. 20 mm).
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.
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| :| Focal width of the eyepiece| | =|
Magnification
---|---|---|---|---|---
Let’s calculate:| 900 mm| :| 20 mm| =| 45x
| 900 mm| :| 12 mm| =| 75x
| 900 mm| :| 4 mm| =| 225x
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.
Dismantling the Telescope
Hopefully your observation session will have been interesting and successful;
afterwards, it is recommended to store the telescope in a dry and well-
ventilated room. Please do not forget to place the lens caps back onto the
front tube opening and the eyepiece holder. All eyepieces and optical
accessories should also be stored in their respective containers.
TIP:
The inverting lens is not suitable for astronomi-cal observation. Here, work
with just the zenith mirror and an eyepiece. For terrestrial observa-tions and
for viewing nature, you may use the inverting lens with an eyepiece.
Troubleshooting
Problem | Solution |
---|---|
No image | Remove lens cap from lens opening |
Fuzzy image
| ****
Adjust focus with focus adjustment knob
Focusing is not possible| Wait for temperatures inside tube to balance out
(about 30 minutes)
Bad image| Never observe through a pane of glass.
Object of observation is visible in finder,
but not in telescope
| Align finder (see chapter 7)
Sluggish or stiff steering of the shafts| Balance telescope
Image is “askew,” even with zenith mirror| The eyepiece holder in the zenith
mirror must be aligned vertically
Technical data
- Double-lens system (achromatic) made of glass
- Alt-azimuth mount with equatorial wedge (Optimised mounting system with flexible shafts)
- Magnification: 45x – 337.5x
- Lens Diameter: 70 mm
- Focal Length: 900 mm
- 3 eyepieces: K-20 / K-12 / K-4 mm
- Diagonal Mirror
- 6×25 Viewfinder
- 1,5x Erecting lens
- Adjustable Aluminium Tripod
Possible objects for observation:
We have compiled and explained a number of very interesting celestial bodies and star clus-ters for you. On the accompanying images at the end of the instruction manual, you can see how objects will appear in good viewing condi- tions through your telescope using the eyepie-ces that came with it.
The Moon
The moon is the Earth’s only natural satellite. Figure 19)
Diameter: 3.476 km
Distance: approx. 384 401 km
The moon has been known to humans since prehistoric times. It is the second
brightest object in the sky (after the sun). Because the moon circles the
Earth once per month, the ang-le between the Earth, the moon and the sun is
constantly changing; one sees this change in the phases of the moon. The time
between two consecutive new moon phases is about 29.5 days (709 hours).
Orion Nebula (M 42)
M 42 in the Orion constellation (Figure 20) Right ascension: 05:32.9 (Hours:
Minutes) Declination: -05:25 (Degrees: Minutes) Distance: 1.500 light years
With a distance of about 1500 light years, the Orion Nebula (Messier 42,
abbreviation: M 42) is the brightest diffuse nebula in the sky – visible with
the naked eye, and a rewarding object for telescopes in all sizes, from the
smallest field glass to the largest earthbound observatories and the Hubble
Space Telescope.
When talking about Orion, we‘re actually refer-ring to the main part of a much
larger cloud of hydrogen gas and dust, which spreads out with over 10 degrees
over the half of the Orion con-stellation. The expanse of this enormous cloud
stretches several hundred light years.
Ring Nebula in Lyra constellation (M 57)
M 57 in the Lyra constellation (Figure 21) Right ascension: 18:51.7 (Hours:
Minutes) Declination: -+32:58 (Degrees: Minutes) Distance: 2.000 light years
The famous Ring Nebula M 57 in the constel-lation of Lyra is often viewed as
the prototype of a planetary nebula; it is one of the magni-ficent features of
the Northern Hemisphere’s summer sky. Recent studies have shown that it is
probably comprised of a ring (torus) of brightly shining material that
surrounds the central star (only visible with larger tele-scopes), and not of
a gas structure in the form of a sphere or an ellipsis. If you were to look at
the Ring Nebula from the side, it would look like the Dumbbell Nebula (M27).
With this object, we’re looking directly at the pole of the nebula.
Dumbbell Nebula in the Vulpecula (Fox) cons-tellation (M 27)
M 27 in the Fox constellation (Figure 22) Right ascension: 19:59.6 (Hours:
Minutes) Declination: -+22:43 (Angle: Minutes) Distance: 1.250 light years
The Dumbbell Nebula (M 27) in Fox was the first planetary nebula ever
discovered. On July 12, 1764, Charles Messier discovered this new and
fascinating class of objects. We see this object almost directly from its
equatorial plane. If you could see the Dumbbell Nebula from one of the poles,
it would probably reveal the shape of a ring, and we would see something very
similar to what we know from the Ring Nebula (M 57). In reasonably good
weather, we can see this ob-ject well even with small
magnifications.
Telescope ABC’s
What do the following terms mean?
Barlow Lens:
The Barlow Lens was named after its inventor, Peter Barlow, a British
mathematician and phy-sicist who lived from 1776-1862. The lens can be used to
increase the focal width of a tele-scope. Depending on the type of lens, it is
pos-sible to double or even to triple the focal width. As a result, the
magnification can of course also be increased. See also “Eyepiece.“
Focal width:
Everything that magnifies an object via an op-tic (lens) has a certain focal
width. The focal width is the length of the path the light travels from the
surface of the lens to its focal point. The focal point is also referred to as
the focus. In focus, the image is clear. In the case of a te-lescope, the
focal widths of the telescope tube and the eyepieces are combined:
Lens:
The lens turns the light which falls on it around in such a way so that the
light gives a clear image in the focal point after it has traveled a certain
distance (focal width).
Eyepiece:
An eyepiece is a system made for your eye and comprised of one or more lenses.
In an eyepie-ce, the clear image that is generated in the focal point of a
lens is captured and magnified still more.
There is a simple formula for calculating the magnification:
Focal width of the telescope tube / Focal width of the eyepiece =
Magnification
You see: In a telescope, the magnification de-pends on both the focal
width of the telescope tube and the focal width of the eyepiece.
From this formula, we see that if you use an eyepiece with a focal width of 20
mm and a te-lescope tube with a focal width of 600 mm, you will get the
following magnification:
600 mm / 20 mm = 30 times magnification
Inverting lens:
The inverting lens is set into the eyepiece holder of the telescope before the
eyepiece itself. This lens can produce an additional magnification (mostly
around 1.5x) via the integrated lens in the eyepiece. As the name suggests,
the image will be turned around if you use an inverting lens, and appears
upright and even properly ori-ented on the vertical axis.
Magnification:
The magnification corresponds to the difference between observation with the
naked eye and observation through a magnification apparatus (e.g. a
telescope). In this scheme, observation with the eye is considered “single”,
or 1x magni-fication. Accordingly, if a telescope has a mag-nification of 30x,
then an object viewed through the telescope will appear 30 times larger than
it would with the naked eye. See also “Eyepiece.“
Zenith mirror:
A mirror that deflects the ray of light 90 de-grees. With a horizontal
telescope tube, this device deflects the light upwards so that you can
comfortably observe by looking downwards into the eyepiece. The image in a
zenith mirror appears upright, but rotated around its vertical axis (what is
left appears right and vice versa).
Bresser GmbH Gutenbergstraße 2
46414 Rhede · Germany
www.bresser.de
@BresserEurope
Bresser UK Ltd.
Suite 3G, Eden House Enterprise Way, Edenbridge, Kent TN8 6HF, Great Britain
SERVICE AND WARRANTY
TELESCOPE GUIDE:
TELESCOPE FAQ:
DOWNLOADS:
References
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