INSTRUCTION MANUAL
Orion®
EQ-2 Equatorial Mount
#9828 Equatorial Mount
Providing Exceptional Consumer Optical Products Since 1975
Customer Support (800) 676-1343
E-mail: support@telescope.com
Corporate Offices (831) 763-7000
89 Hangar Way, Watsonville, CA 95076
IN 168 Rev. B 04/09
Dec. setting circle
R.A. setting circle
Latitude lock t-bolt
Latitude adjustment t-bolt
Dec. slow-motion control cable
Azimuth lock knob
Counterweight
Counterweight lock knob
Counterweight shaft
R.A. slow-motion control cable
Accessory tray
Accessory tray bracket
Accessory tray bracket
attachment point
Leg lock knob
Figure 1. EQ-2 Mount
Congratulations on your purchase of a quality Orion product. Your new EQ-2 Equatorial Mount was
designed to work with many different telescope optical tubes. Designed for astronomical use, this precision mount allows convenient manual “tracking” of celestial objects as they move slowly across the sky,
so they remain within your eyepiece’s field of view. The setting circles will assist you in locating hundreds
of fascinating celestial denizens, including galaxies, nebulas, and star clusters, from their catalogued
coordinates. With a little practice and a little patience, you’ll find that your EQ-2 Equatorial Mount is an
invaluable tool for getting the most out of your astronomical observing sessions.
These instructions will help you set up and properly use your equatorial mount. Please read them over
thoroughly before getting started.
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Table of Contents
1. Unpacking ............................................................................................................................. 3
2. Assembly .............................................................................................................................. 3
3. Attaching a Telescope ........................................................................................................... 4
4. Balancing a Telescope .......................................................................................................... 4
5. Setting Up and Using the Equatorial Mount ............................................................................ 5
6. Specifications .......................................................................................................................... 8
1. Unpacking
The entire mount will arrive in one box. Be careful unpacking
the box. We recommend keeping the box and all the internal
shipping containers. In the event that the mount needs to be
shipped to another location, or returned to Orion for warranty
repair, having the proper box and internal shipping containers
will help ensure that your mount will survive the journey
intact.
Make sure all the parts in the Parts List are present. Be sure
to check all packaging carefully, as some parts are small. If
anything appears to be missing or broken, immediately call
Orion Customer Support (800-676-1343) or email support@
telescope.com for assistance.
2. Assembly
Assembling the mount for the first time should take about 20
minutes. No tools are needed, other than the ones provided.
All bolts should be tightened securely to eliminate flexing and
wobbling, but be careful not to over-tighten or the threads may
strip. Refer to Figure 1 during the assembly process.
1. Lay the equatorial mount on its side. Attach the tripod legs
one at a time to the mount by sliding the bolts installed in
the tops of the tripod legs into the slots at the base of the
mount and tightening the wing nuts finger-tight. Note that
the accessory tray bracket attachment point on each leg
should face inward.
2. Tighten the leg lock knobs on the bottom braces of the tripod legs. For now, keep the legs at their shortest (fully
retracted) length; you can extend them to a more desirable
length later, after the telescope is completely assembled.
3. With the tripod legs now attached to the equatorial mount,
stand the tripod upright (be careful!) and spread the legs
apart enough to connect each end of the accessory tray
bracket to the attachment point on each leg. Use the screw
that comes installed in each attachment point to do this.
First remove the screw using the supplied screwdriver,
then line up one of the ends of the bracket with the attachment point and reinstall the screw. Make sure that the
Parts List
Box #1: Optical Tube Assembly and Accessories
Qty. Description
1 German-type equatorial mount
2 Slow-motion control cables
1 Counterweight
1 Counterweight shaft
3 Tripod legs w/attachment bolts
1 Tripod accessory tray w/mounting hardware
1 Accessory tray bracket
accessory tray bracket is oriented so that the ribs in its
plastic molding face downwards.
4. Now, with the accessory tray bracket attached, spread the
tripod legs apart as far as they will go, until the bracket is
taut.
5. Attach the accessory tray to the accessory tray bracket
with the three wing screws already installed in the tray.
This is done by pushing the wing screws up through the
holes in the accessory tray bracket, and threading them
into the holes in the accessory tray.
6. Next, tighten the bolts at the tops of the tripod legs, so the
legs are securely fastened to the equatorial mount. Use
the provided wrench and your fingers to do this.
7. Orient the equatorial mount as it appears in Figure 2, at a
latitude of about 40°, i.e., so the pointer next to the latitude
scale (located directly above the latitude lock t-bolt) is
pointing to the mark at “40.” To do this, loosen the latitude
lock t-bolt, and turn the latitude adjustment t-bolt until the
pointer and the “40” line up. Then retighten the latitude lock
t-bolt. The declination (Dec.) and right ascension (R.A.)
axes may need re-positioning (rotation) as well. Be sure to
loosen the R.A. and Dec. lock knobs before doing this.
Retighten the R.A. and Dec. lock knobs once the equatorial
mount is properly oriented.
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8. Slide the counterweight onto the counterweight shaft.
Make sure the counterweight lock knob is adequately
loosened to allow the counterweight shaft to pass
through the hole in the counterweight.
9. Now, with the counterweight lock knob still loose, grip the
counterweight with one hand and thread the shaft into the
equatorial mount (at the base of the declination axis) with
the other hand. When it is threaded as far in as it will go,
position the counterweight about halfway up the shaft and
tighten the counterweight lock knob. The retaining screw
and washer on the bottom of the shaft prevent the counterweight from falling off (and onto your foot!) if the
counterweight lock knob becomes loose.
10. Attach the two slow-motion cables to the R.A. and Dec.
worm gear shafts of the equatorial mount by positioning
the thumb screw on the end of the cable over the indented
slot on the worm gear shaft and then tightening the thumb
screw. We recommend that the shorter cable be used on
the R.A. worm gear shaft and the longer cable on the Dec.
worm gear shaft.
The equatorial mount is now fully assembled and should
appear as shown in Figure 1.
3. Attaching A Telescope
The EQ-2 Equatorial Mount is designed to hold small to midsize telescopes weighing up to about 10 lbs. For heavier
telescopes, the mount may not provide sufficient stability for
steady imaging. Any type of telescope can be mounted on the
EQ-2 Equatorial mount, including refractors, Newtonian reflectors, and cadadioptrics, provided a 1/4”-20 adapter or set of
tube rings is available to couple the tube to the mount.
Orion carries a variety of differently sized tube rings and a
1/4"-20 mounting adapter designed exclusively for the EQ-2
Equatorial Mount. One of these items probably fits the telescope tube you wish to mount. Check the Orion print or online
catalogs for currently available mounting accessories.
4. Balancing the Telescope
Once the telescope is attached to the equatorial mount, the
next step is to balance the telescope. Proper balance is
required to insure smooth movement of the telescope on both
axes of the equatorial mount.
If you attach your telescope with a 1/4”-20 adapter, it may not
be possible to balance the scope precisely with respect to the
Figure 2. The equatorial mount.
Dec. slow-motion control cable
Dec. setting circle
Latitude scale
Latitude adjustment t-bolt
Dec. lock knob
R.A. lock knob
DECLINATION AXIS
RIGHT ASCENSION AXIS
R.A. setting circle
lock thumbscrew
Latitude lock t-bolt
Azimuth lock knob
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R.A. setting circle
R.A. slow- motion control cable
3a
3c
Figure 3A, 3B, 3C, 3D: Proper operation of the equatorial
mount requires balancing the telescope tube on the R.A.
axis. (a) With the R.A. lock knob released, slide the
counterweight along the counterweight shaft until it just
counterbalances the tube. (b) When you let go with both
hands, the tube should not drift up or down. (c) With the
Dec. lock knob released, loosen the tube ring lock
clamps a few turns and slide the telescope forward or
back in the tube rings. (d) When the tube is balanced
about the Dec. axis, it will not move when you let go.
3d
3b
5. Loosen the tube ring clamps a few turns until you can slide
the telescope tube forward and back inside the rings (this
can be aided by using a slight twisting motion on the optical
tube while you push or pull on it). Position the telescope so
that it remains horizontal when you carefully let go with both
hands. This is the balance point for the Dec. axis (Figure 3d).
Before clamping the rings tight again, rotate the telescope
so that the eyepiece is at a convenient angle for viewing.
The telescope is now balanced on both axes. Now when you
loosen the lock knob on one or both axes and manually point
the telescope, it should move without resistance and should
not drift from where you point it.
5. Setting Up and Using
the Equatorial Mount
When you look at the night sky, you no doubt have noticed that
the stars appear to move slowly from east to west over time.
That apparent motion is caused by the Earth’s rotation (from
west to east). An equatorial mount (Figure 2) is designed to
compensate for that motion, allowing you to easily “track” the
movement of astronomical objects, thereby keeping them from
drifting out of the telescope’s field of view while you’re observing.
This is accomplished by slowly rotating the telescope on its right
ascension (R.A.) axis, using only the R.A. slow-motion cable.
But first the R.A. axis of the mount must be aligned with the
Earth’s rotational (polar) axis - a process called polar alignment.
declination axis. This is because the telescope cannot be
repositioned as it can when tube rings are used.
Assuming you will be using tube rings, we will first balance the
telescope with respect to the R.A. axis, then the Dec. axis:
1. Keeping one hand on the telescope optical tube, loosen the
R.A. lock knob. Make sure the Dec. lock knob is locked, for
now. The telescope should now be able to rotate freely about
the R.A. axis. Rotate it until the counterweight shaft is parallel to the ground (i.e., horizontal).
2. Now loosen the counterweight lock knob and slide the weight
along the shaft until it exactly counterbalances the telescope
(Figure 3a). That’s the point at which the shaft remains horizontal even when you let go of the telescope with both hands
(Figure 3b). If you position the counterweight all the way at
the end of the shaft (near the retaining bolt and washer) and
it still does not counterbalance the telescope, you will need
to purchase an additional counterweight. Retighten the
counterweight lock knob. The telescope is now balanced on
the R.A. axis.
3. To balance the telescope on the Dec. axis, first tighten the
R.A. lock knob, with the counterweight shaft still in the horizontal position.
4. With one hand on the telescope optical tube, loosen the Dec.
lock knob. The telescope should now be able to rotate freely
about the Dec. axis.
Polar Alignment
For Northern Hemisphere observers, approximate polar alignment is achieved by pointing the mount’s R.A. axis at the North
Star, or Polaris. It lies within 1° of the north celestial pole
(NCP), which is an extension of the Earth’s rotational axis out
into space. Stars in the Norther n Hemisphere appear to
revolve around the NCP.
To find Polaris in the sky, look north and locate the pattern of
the Big Dipper (Figure 4). The two stars at the end of the “bowl”
of the Big Dipper point right to Polaris.
Observers in the Southern Hemisphere aren’t so fortunate to
have a bright star so near the south celestial pole (SCP). The
star Sigma Octantis lies about 1° from the SCP, but it is barely
visible with the naked eye (magnitude 5.5).
For general visual observation, an approximate polar alignment is sufficient.
Level the equatorial mount by adjusting the length of the three
tripod legs.
Loosen the latitude lock t-bolt. Turn the latitude adjustment
t-bolt and tilt the mount until the pointer on the latitude scale is
set at the latitude of your observing site. If you don’t know your
latitude, consult a geographical atlas to find it. For example, if
your latitude is 35° North, set the pointer to 35. Then retighten
the latitude lock t-bolt. The latitude setting should not have to
be adjusted again unless you move to a different viewing location some distance away.
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Little Dipper
(in Ursa Minor)
Big Dipper
(in Ursa Major)
N.C.P.
Polaris
Stars
Pointer
Figure 4: To find Polaris in the night sky, look north and
find the Big Dipper. Extend an imaginary line from the
two “Pointer Stars” in the bowl of the Big Dipper. Go
about five times the distance between those stars and
you’ll reach Polaris, which lies within 1° of the north
celestial pole (NCP).
Loosen the Dec. lock knob and rotate the telescope optical tube
until it is parallel with the R.A. axis. The pointer on the Dec. setting circle should read 90°. Retighten the Dec. lock lever.
Loosen the azimuth lock knob at the base of the equatorial
mount and rotate the mount so the telescope tube (and R.A.
axis) points roughly at Polaris. If you cannot see Polaris directly from your observing site, consult a compass and rotate the
mount so the telescope points North. Retighten the azimuth
lock knob.
The equatorial mount is now polar aligned for casual observing. More precise polar alignment is recommended for
astrophotography.
From this point on in your observing session, you should not
make any further adjustments in the azimuth or the latitude of
the mount, nor should you move the tripod. Doing so will undo
the polar alignment. The mount should be moved only about
its R.A. and Dec. axes.
Use of the R.A. and Dec. Slow-Motion
Control Cables
The R.A. and Dec. slow-motion control cables allow fine
adjustment of the telescope’s position to center objects within
the field of view. Before you can use the cables, you must
manually “slew” the mount to point the telescope in the vicinity
of the desired target. Do this by loosening the R.A. and Dec.
lock knobs and moving the telescope about the mount’s R.A.
and Dec. axes. Once the telescope is pointed somewhere
close to the object to be viewed, retighten the mount’s R.A.
and Dec. lock knobs.
The object should now be visible somewhere in the telescope’s finder scope. If it isn’t, use the slow-motion controls to
scan the surrounding area of sky. When the object is visible in
the finder scope, use the slow-motion controls to center it.
Now, look in the telescope’s eyepiece. If the finder scope is
properly aligned, the object should be visible somewhere in
the field of view. Once the object is visible in the eyepiece, use
the slow-motion controls to center it in the field of view.
The Dec. slow-motion control cable can move the telescope a
maximum of 25°. This is because the Dec. slow-motion mech-
Cassiopeia
anism has a limited range of mechanical travel. (The R.A.
slow-motion mechanism has no limit to its amount of travel.) If
you can no longer rotate the Dec. control cable in a desired
direction, you have reached the end of travel, and the slowmotion mechanism must be reset. This is done by first rotating
the control cable several turns in the opposite direction from
which it was originally being turned. Then, manually slew the
telescope closer to the object you wish to observe (remember
to first loosen the Dec. lock knob). You should now be able to
use the Dec. slow-motion control cable again to fine adjust the
telescope’s position.
Tracking Celestial Objects
When you observe a celestial object through the telescope,
you’ll see it drift slowly across the field of view. To keep it in the
field, if your equatorial mount is polar aligned, just turn the
R.A. slow-motion control cable clockwise. The Dec. slowmotion control cable is not needed for tracking. Objects will
appear to move faster at higher magnifications, because the
field of view is narrower.
Optional Motor Drives for Automatic Tracking
An optional DC motor drive can be mounted on the R.A. axis
of the equatorial mount to provide hands-free tracking. Objects
will then remain stationary in the field of view without any
manual adjustment of the R.A. slow-motion control cable.
Understanding the Setting Circles
The setting circles on an equatorial mount enable you to
locate celestial objects by their “celestial coordinates”. Every
object resides in a specific location on the “celestial sphere”.
That location is denoted by two numbers: its right ascension
(R.A.) and declination (Dec.). In the same way, every location
on Earth can be described by its longitude and latitude. R.A. is
similar to longitude on Earth, and Dec. is similar to latitude.
The R.A. and Dec. values for celestial objects can be found in
any star atlas or star catalog.
The R.A. setting circle is scaled in hours, from 1 through 24,
with small marks in between representing 10-minute increments (there are 60 minutes in 1 hour of R.A.). The lower set
of numbers (closest to the plastic R.A. gear cover) apply to
viewing in the Northern Hemisphere, while the numbers above
them apply to viewing in the Southern Hemisphere. The R.A.
coordinate indicator arrow is between the “R” and the “A” on
the plastic R.A. gear cover (see Figure 5); ignore the metal
pointer on the R.A. axis of the mount.
The Dec. setting circle is scaled in degrees, with each mark
representing 1° increments. Values of Dec. coordinates range
from +90° to -90°. The 0° mark indicates the celestial equator
(see Figure 5). When the telescope is pointed nor th of the
celestial equator, values of the Dec. setting circle are positive,
while when the telescope is pointed south of the celestial
equator, values of the Dec. setting circle are negative.
So, the coordinates for the Orion Nebula listed in a star atlas
will look like this:
R.A. 5h 35.4m Dec. -5° 27’
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That’s 5 hours and 35.4 minutes in right ascension, and -5
degrees and 27 arc-minutes in declination (there are 60 arcminutes in 1 degree of declination).
Before you can use the setting circles to locate objects, the
mount must be well polar aligned, and the R.A. setting circle
must be calibrated. The Dec. setting circle has been permanently calibrated at the factory, and should read 90° whenever
the telescope optical tube is parallel with the R.A. axis.
Calibrating the Right Ascension Setting Circle
1. Identify a bright star in the sky near the celestial equator
(Dec. = 0°) and look up its coordinates in a star atlas.
2. Loosen the R.A. and Dec. lock knobs on the equatorial
mount, so the telescope optical tube can move freely.
3. Point the telescope at the bright star whose coordinates you
know. Lock the R.A. and Dec. lock knobs. Center the star in the
telescope’s field of view with the slow-motion control cables.
Celestial equator (Dec. = 0°)
Dec. coordinate indicator arrow
4. Loosen the R.A. setting circle lock thumb screw (see Figure
2); this will allow the setting circle to rotate freely. Rotate the
setting circle until the arrow between the “R” and the “A” on
the plastic gear cover indicates the R.A. coordinate listed in
the star atlas for the object. Retighten the thumb screw.
Finding Objects With the Setting Circles
Now that both setting circles are calibrated, look up in a star
atlas the coordinates of an object you wish to view.
1. Loosen the Dec. lock knob and rotate the telescope until the
Dec. value from the star atlas matches the reading on the
Dec. setting circle. Remember that values of the Dec. setting circle are positive when the telescope is pointing north
of the celestial equator (Dec. = 0°), and negative when the
telescope is pointing south of the celestial equator. Retighten
the lock knob.
2. Loosen the R.A. lock knob and rotate the telescope until the
R.A. value from the star atlas matches the reading on the
R.A. setting circle. Remember to use the lower set of numbers on the R.A. setting circle. Retighten the lock knob.
Most setting circles are not accurate enough to put an object
dead-center in the telescope’s eyepiece, but they should place
the object somewhere within the field of view of the finder
scope, assuming the equatorial mount is accurately polar
aligned. Use the slow-motion controls to center the object in
the finder scope, and it should appear in the telescope’s field
of view.
Use these numbers on
the R.A. setting circle
Plastic R.A.
gear cover
(Northern Hemisphere)
R.A. coordinate
indicator arrow
Figure 5: For Northern Hemisphere observers, use the
lower set of numbers on the R.A. setting circle. The R.A.
coordinate indicator arrow is between the “R” and the
“A” on the plastic gear cover. The telescope (not shown)
is pointing north of the celestial equator, so the
approximate coordinates of the mount in the image are
R.A. 8h 30m Dec. 60°.
Confused About Pointing the Telescope?
Beginners occasionally experience some confusion about
how to point the telescope overhead or in other directions. In
Figure 1 the telescope is pointed north, as it would be during
polar alignment. The counterweight shaft is oriented downward. But it will not look like that when the telescope is pointed
in other directions. Let’s say you want to view an object that is
directly overhead, at the zenith. How do you do it?
One thing you DO NOT do is make any adjustment to the latitude adjustment t-bolt. That will nullify the mount’s polar
alignment. Remember, once the mount is polar aligned, the
telescope should be moved only on the R.A. and Dec. axes. To
point the scope overhead, first loosen the R.A. lock knob and
rotate the telescope on the R.A. axis until the counterweight
shaft is horizontal (parallel to the ground). Then loosen the
Dec. lock knob and rotate the telescope until it is pointing
straight overhead. The counterweight shaft is still horizontal.
Then retighten both lock knobs.
Similarly, to point the telescope directly south, the counterweight shaft should again be horizontal. Then you simply rotate
the scope on the Dec. axis until it points in the south direction.
What if you need to aim the telescope directly north, but at an
object that is nearer to the horizon than Polaris? You can’t do
it with the counterweight down as pictured in Figure 1. Again,
you have to rotate the scope in R.A. so the counterweight
shaft is positioned horizontally. Then rotate the scope in Dec.
so it points to where you want it near the horizon.
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To point the telescope to the east or west, or in other directions, you rotate the telescope on its R.A. and Dec. axes.
Depending on the altitude of the object you want to observe,
the counterweight shaft will be oriented somewhere between
vertical and horizontal.
Figure 6 illustrates how the telescope will look pointed at the
four cardinal directions - north, south, east, and west
The key things to remember when pointing the telescope is that
a) you only move it in R.A. and Dec., not in azimuth or latitude
(altitude), and b) the counterweight and shaft will not always
appear as it does in Figure 1. In fact, it almost never will!
6. Specifications
Mount: German-type equatorial
Tripod: Aluminum
Height: 38” to 58”
Weight: 17 lbs
Counterweight: 5 lb. supplied
Maximum loading weight: About 10 lbs
Slow-motion adjustment: on both RA and Dec axes
Setting circles: RA scaled in 10 min. increments, Dec scaled
in 1° increments, for N or S Hemisphere
Polar axis latitude adjustment: 5° to 75°
6a 6b
6c 6c
Figure 6A, 6B, 6C, 6D: This illustration shows the
telescope pointed in the four cardinal directions: (a)
north, (b) south, (c) east, (d) west. Note that the tripod
and mount have not been moved; only the telescope
tube has been moved on the R.A. and Dec. axes.
One-Year Limited Warranty
This Orion Product is warranted against defects in materials or workmanship for a period of one year
from the date of purchase. This warranty is for the benefit of the original retail purchaser only. During this
warranty period Orion Telescopes & Binoculars will repair or replace, at Orion’s option, any warranted
instrument that proves to be defective, provided it is returned postage paid to: Orion Warranty Repair, 89
Hangar Way, Watsonville, CA 95076. If the product is not registered, proof of purchase (such as a copy of
the original invoice) is required.
This warranty does not apply if, in Orion’s judgment, the instrument has been abused, mishandled, or
modified, nor does it apply to normal wear and tear. This warranty gives you specific legal rights, and you
may also have other rights, which vary from state to state. For further warranty service information, contact: Customer Service Department, Orion Telescopes & Binoculars, 89 Hangar Way, Watsonville, CA
95076; (800) 676-1343.
Orion Telescopes & Binoculars
89 Hangar Way, Watsonville, CA 95076
Customer Support Help Line (800) 676-1343 • Day or Evening
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