Instruction Manual
Instruction Manual
Omegon 130/920 EQ-3
English version 12.2014 Rev A
The Omegon® 130/920 EQ-3
Congratulations on the purchase of the new Omegon® 130/920 EQ-2. This small telescope will give
you hours of fun, with its all optical glass lens and super compactness, and it is the ideal companion
to start in the world of amateur astronomy. With this telescope you will be able to see the craters on
the Moon, star clusters, some nebulae a glimpse of the Jupiter disc features and its Galilean moons
and the rings of Saturn. We have included many accessories so it will be easy to use this telescope.
1. Included parts
We have included several accessories that will make the use of the telescope easier and fun, please
take a look at the list of the parts so you can identify them in the future.
1. & 2. Two eyepieces 1.25” (31.75mm); a Kellner 25mm and a Kellner 10mm eyepiece;
3. 2x magnification Barlow Lens;
4. Red-dot finderscope;
2. Getting Started. It is very simple to get
started. Here is how the telescope works. The
telescope should point to the object being
observed. The mirror at the bottom of the
telescope’s tube gathers the object’s light and
reflects it to the secondary mirror that brings
it to the eyepiece. Next to the telescope’s
aperture there is the focuser. The focuser
tube moves to get a precise focused image. At
the focuser one can use the supplied
accessories. Different combinations of
accessories give different results, such as
different image magnifications or correct
image. All this will be explained in more detail
on the next pages.
3. Assembly. Start by setting up the tripod.
Figure 1. Parts list.
Open the tripod legs as shown (figure 2). Place the tripod tray and thread it (figure 3). You can use
the tray to put your eyepieces or other observing accessories. Place the equatorial head on top of
the tripod (figure 4). Next place the tube rings on the mount (figure 5), tighten it securely, and insert
the counterweight shaft by threading it to the Right Ascension (R.A.) axis. Insert the counterweight
(figure 7), don’t forget to thread the foot-saver (the screw and washer at the end of the shaft). Place
the optical tube by opening the tube rings. Slide it so that the tube stays centred with the rings
(figure 8). Install the fine movement handles as shown in the protruding shafts. Remove the two
thumbscrews (figure 10) and install the red-dot finder (figure 11) as shown, the finder should point
to the same direction as the telescope. Congratulations! You are almost ready to use the telescope!
Figure 2. Tripod assembly.
Figure 3. Tray placement.
Figure 4. Place equatorial head on top of tripod.
Figure 5. Place the tube rings.
Figure 6. Insert fine shaft.
Figure 7. Place the counterweight.
Figure 8. Tube placement.
Figure 9. Fine movement handles.
Figure 10. Finderscope placement.
Figure 11. Finderscope placement.
4. Start using your Omegon® 130/920 EQ-3 telescope. Point the telescope to a distant object
during the day. It is important to do this during daylight, so that you get familiarized with the
telescope operation. A good target is a church tower, a chimney or a distant mountain peak.
Rotate the focuser knob, so that the focuser tube moves in and out. Do this slowly. We suggest that
you start by racking the focuser all the way in and slowly move it out. With the K25mm eyepiece you
should be able to get a focused image easily. 4.1. The Finderscope. Before we mentioned the
finderscope as a valuable tool to point the telescope at an object. To operate properly, the telescope
and the finderscope should be aligned. The image obtained through the finderscope has a much
broader field of view than that of the telescope. 4.2. How to align the finderscope? You have the
house chimney (example mentioned before) centered at the telescope eyepiece field of view. Now
look through the finderscope. The small red-dot at the center of the finderscope field of view should
match the center of the telescope field of view. Adjust the two finderscope screws to get the cross
pointing to the same object as the telescope (as shown in Figure 4.2.1.).
4.2.1. A distant object is centered at the telescope’s
field of view. In this example we have a house with a
chimney. The chimney is the reference point to
place at the center of the field of view. We first look
through the telescope with the lowest magnification
possible (PL25mm should be preferrable), so we
have the widest field of view.
4.2.2. Looking through the finderscope (it should be
powered on) we see the same building ,but in this
case the red dot and chimney are not centered. We
adjust the finderscope using the two thumbscrews
(figure below) so that the finderscope red point
moves slightly until it matches the chimney. This is
enough to correct the objects position in the
finderscope. Trial and error is required to get a
satisfactory result.
4.2.3. After playing with the two findercope
thumbscrews and some trial and error, we get the
finderscope red dot close to the center (in this case
the chimney). The finderscope is now ready to use!
5. Using the accessories, a bit of math to
understand how all it works.
This means that the PL25 eyepiece provides a
36x power (magnification). This seems low,
but when you try it, you will see a bright
image with some (very good) details.
Using the accessories is easy and fun. To
change magnification simply swap eyepieces.
To get more magnification simply use the
barlow lens. But how does all of this work?
5.2. Barlow Lens
The barlow lens is a very interesting device. It
is a negative lens, that multiplies the
telescope’s focal length. So a 2x Barlow
multiplies the original focal length by 2x, in
this case 920𝑚𝑚 𝑥 2 = 1840𝑚𝑚.
A 3x Barlow lens multiplies by 3x.
Your telescope is supplied with a 2x Barlow
lens. When used with the PL25mm eyepiece
you get 2x the power obtained before
36 𝑝𝑜𝑤𝑒𝑟 𝑋 2𝑥 𝐵𝑎𝑟𝑙𝑜𝑤 = 72 𝑝𝑜𝑤𝑒𝑟
5.1. Power (magnification)
Your telescope has a focal length of 920mm.
This is approximately the distance between
the telescope lens and its focal point (very
similar to the distance between the focus
point of a loupe and the loupe lens). This is a
very important feature, that allows to
determine several interesting facts such as
5.3. Erecting lens (not included)
The magnification is determined by the
telescope’s focal length and the used
eyepiece. You probably noticed that the two
supplied eyepieces are PL25mm and PL10mm.
This means that the PL25mm is a 25mm focal
length eyepiece while the PL10mm is a 10mm
focal length eyepiece.
The erecting lens gets you an upright image
view with the telescope. It also adds some
power like the barlow lens. The supplied
Erecting Lens provides an extra 1.5x power.
5.4. Diagonal Mirror (does not apply to this
To determine the magnification just divide the
telescope’s focal length by the eyepiece’s
focal length. Let’s give an example for our
telescope and the supplied eyepieces:
This diverts the light coming from the
telescope to an angle of 45 or 90 degrees. It is
useful because it provides a more confortable
position when observing.
Telescope’s focal length is 920mm.
PL25 eyepiece’s focal length is 25mm.
Here are some examples on how to use the
= 36 𝑝𝑜𝑤𝑒𝑟
Some possible accessory combinations
Barlow Lens 2x
PL25mm Eyepiece
PL10mm Eyepiece
Does not apply
Deep Sky
Jupiter and
6. What can been seen with this telescope?
Below you will find some examples of what you can expect to see when using this telescope.
6.1. The Moon is one of the most spectular objects
to be seen through a telescope. Even a small
telescope will reveal high detail of the Moon’s
surface. You will be able to see the craters on the
Moon’s surface and other features like the Marea.
The moon is a very bright object. It is better to
observe it when the Moon is not full. Try the
crescent Moon and look for features along the
terminator (between illuminated and dark surfaces).
6.2. Jupiter is the biggest planet of our solar system.
It is also one of the favorite targets for beginners.
Galileo was able to discover that the four tiny dots
that turn around the planet were in fact part of
Jupiters system of moons. With this telescope you
will not only be able to see Jupiter’s planet disc with
its two major discernible bands, but also its biggest
moons, Io, Europa, Ganymedes and Callisto.
6.3. The “lord of the rings” of the night skies, Saturn
is by far the most popular target for small
telescopes. Saturn’s rings are discernible even at
60x magnification. In a very good night you will be
able to see the Cassini’s division (the darker band
on the Saturn’s rings).
7. Troubleshooting and frequently asked questions
Q: I get a mirrored view of the objects. Like if they were reversed, and R shows up like
R: This is caused by the telescope’s mirrors. To get a corrected image it is necessary to use the
correcting lens and the eyepiece as shown below. Please notice this telescope is not designed for
terrestrial viewing.
Q: I use the finderscope to point to objects but I always miss the target.
A: You probably need to realign the finderscope. Please proceed as described in 4.2.
Q: When I use the barlow lens and the PL10mm eyepiece the image is so dark I can hardly see
A: Power should be used with moderation. It depends on how stable the atmosphere is, too much
turbulence causes image distortion. Usually the limit is 2x for each millimeter of the telescope
aperture. In this case the telescope has an aperture of 130mm, so in a very good night you should be
able to reach 260x. The more magnified the image is, the darker it gets.
Q: Is my telescope compatible with other eyepieces ?
A: Omegon telescopes are compatible with all telescope eyepieces from different manufacturers as
long as the eyepiece is a 1.25” (or 31.75mm) size eyepiece. If you would like to test an eyepiece from
a fellow astronomer go ahead. Different eyepieces provide different visual experiences.
Q: I want to use my telescope to take pictures.
A: This telescope is designed for visual use. It doesn’t mean it can’t be used for photography, however
it will be hard to get high quality pictures with this telescope. If you have a smartphone you can shoot
the Moon or some terrestrial objects. Search online for digiscoping and afocal photography.
Q: The stars only appear as points in the telescope.
A: Stars will always only appear as points, even in the largest telescopes in the world. It is more
interesting for beginners to observe two-dimensional objects, such as the Moon or planets. Once you
find these, you will be able to start learning about the astronomical calendar.
Q: I would like to observe the Sun.
A: An appropriate solar filter, placed over the objective, is essential for observing the sun. These are
available as plastic foil or glass filters. They only allow a tiny and harmless fraction of sunlight into
the telescope, when securely positioned over the objective, allowing you to observe the sun in
complete safety. Eyepiece solar filters (not available from us) should be avoided at all costs as they
are considered unsafe.
Note: Never look directly at the sun through a telescope without an objective solar filter!
Q: I can’t see anything when I look through my telescope.
A: The telescope is only suitable for astronomical observing and when used outside at night.
Observing from inside the house or during the day usually is not possible.
The dust caps must first be removed and an eyepiece inserted before you can start observing. Are you
sure you have removed all the dust caps, not just the small ones? If you have not, then no light will
enter the telescope and everything will appear black.
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