Orion ATLAS EQ-G User manual

INSTRUCTION MANUAL
IN 279 Rev. C 01/09
Providing Exceptional Consumer Optical Products Since 1975
Customer Support (800)-676-1343
E-mail: [email protected]
Corporate Offices (831)‑763‑7000
89 Hangar Way, Watsonville, CA 95076
Orion®Atlas™EQ-G
Equatorial Mount
#9996

2
Figure 1. The Atlas EQ-G mount.
Power switch
Power indicator light
12V DC power jack
Auto guider jack
Right Ascension
setting circle
Right Ascension
lock lever
Hand controller jack
Latitude scale
Latitude adjustment L-bolts
Center support shaft
Tripod center support tray
GoTo hand controller
Tube ring mounting plate
Mounting plate lock knobs
Declination lock lever
Declination setting circle
Front opening
Counterweight shaft lock lever
Counterweight shaft
Counterweights
Counterweight lock knobs
“Toe-saver”
GoTo hand controller cable
Tripod leg
Leg lock levers

3
Table of Contents
1. Unpacking............................ 3
2. Parts List............................. 3
3. Assembly ............................ 3
4. Attaching a Telescope................... 4
5. Balancing a Telescope .................. 4
6. Setting Up and Using the Equatorial Mount . . 5
7. The Atlas EQ-G Dual Axis Hand Controller .. 8
8. The Atlas EQ-G GoTo Hand Controller..... 10
9. Specifications ........................ 19
10. Appendices......................... 21
1. Unpacking
The entire mount will arrive in three boxes, one containing
the tripod, one containing the equatorial mount, and one con-
taining the hand controller. Be careful unpacking the boxes.
We recommend keeping the boxes and original packaging.
In the event that the mount needs to be shipped to another
location, or returned to Orion for warranty repair, having the
proper packaging will ensure that your mount will survive the
journey intact.
Make sure all the parts in the Parts List are present. Be
sure to check the box carefully, as some parts are small.
If anything appears to be missing or broken, immediate-
ly call Orion Customer Support (800-676-1343) or email
suppor[email protected] for assistance.
2. Parts List
Box 1: Tripod
Qty. Item
1 Tripod
2 Counterweights (11lbs. each)
1 Tripod center support tray
Box 2: Equatorial Mount
1 Equatorial mount
1 Tube ring mounting plate
1 12V DC Power cable
If you’ve purchased the #7945 Dual-Axis hand controller:
Box 3: Dual-Axis Hand Controller
1 Dual-Axis hand controller
2 Nylon hook-and-loop strips
(1 hook strip, 1 loop strip)
1 Wire clip
If you’ve purchased the #7947 GoTo hand controller:
Box 3: GoTo Hand Controller
1 GoTo hand controller
1 GoTo hand controller cable for Sirius EQ-G
1 GoTo hand controller cable for Atlas EQ-G
1 GoTo hand controller bracket
1 Computer interface cable (RS-232)
1 Wire clip
3. Assembly
Refer to Figure 1 as needed during the assembly process.
1. Stand the tripod legs upright and spread the legs out as
far as they will go. Make certain that the leg lock levers
are tightened. Keep the tripod legs at their shortest (fully
retracted) length, for now; you can extend them to a more
desirable length later, after the mount is fully assembled.
2. Place the base of the equatorial mount onto the tripod
head. Orient the equatorial mount so that the post on the
tripod head lines up with the azimuth adjustment knobs on
the equatorial mount (Figure 2). You may need to loosen
the azimuth adjustment knobs on the equatorial mount in
order to fit the mount onto the tripod head.
Congratulations on your purchase of a quality Orion mount. Your new Atlas EQ-G mount works with many different
optical tubes. Designed for astronomical use, the Atlas EQ-G provides a solid, stable foundation for precise navigation of the
night sky. The internally housed, dual-axis stepper motors provide smooth slewing and tracking of any celestial object. With a
little practice, you’ll find that the Atlas EQ-G 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.
Figure 2. Orient the equatorial head so that the post on the tripod
lines up with the azimuth adjustment knobs on the equatorial mount.
Azimuth
adjustment
knobs
Post

4
3. Thread the center support shaft up through the tripod head
and into the bottom of the equatorial mount until tight. Use
the upper knob on the center support shaft to do this. The
equatorial mount should now be firmly connected to the
tripod.
4. Remove the knob and washer from the bottom of the
center support shaft. Slide the tripod support tray up the
bottom of the central support shaft until the three tray
arms are touching the legs of the tripod. The flat side of
the support tray should be facing up. Make sure the “V” of
each tray arm is against a tripod leg. Place the washer on
the center support shaft against the tray, and follow it by
threading the knob all the way up the center support shaft
until it is tight against the tray. The tripod support tray pro-
vides additional stability for the tripod, and holds up to five
1.25" eyepieces and two 2" eyepieces.
5. Loosen the counterweight shaft lock lever and fully extend
the counterweight shaft. Retighten the lock lever.
6. Remove the knurled “toe saver” retaining screw on the
bottom of the counterweight shaft and slide both counter-
weights onto the shaft. Make sure the counterweight lock
knobs are adequately loosened to allow the counterweight
shaft to pass through the hole. Position the counterweights
about halfway up the shaft and tighten the lock knobs.
Replace the toe saver at the end of the bar. The toe saver
prevents the counterweights from falling on your foot if the
lock knobs happen to come loose.
Your Atlas EQ-G mount is now fully assembled and should
resemble Figure 1 except for the hand controller, which will be
installed and explained in Section 7 (Dual-Axis) or Section 8
(GoTo) of this manual.
4. Attaching a Telescope
The Atlas EQ-G equatorial mount is designed to hold tele-
scope tubes weighing up to approximately 40 lbs. For heavier
telescopes, the mount may not provide sufficient stability for
steady imaging. Any type of telescope can be mounted on the
Atlas EQ-G, including refractors, Newtonian reflectors, and
catadiotropics, provided a set of tube rings is available to cou-
ple the tube to the mount. Orion sells a variety of telescope
tube rings. Please visit our website at OrionTelescopes.com
for details.
1. Attach the tube mounting rings to the tube ring mounting
plate using the screws that come with the tube rings. The
screws should go through the center holes in the ends of
the mounting plate and rethread into the tube rings. Note
that the side of the mounting plate with the central “groove”
will be facing up (Figure 3). Use a small wrench to secure
the tube rings to the mounting plate.
Note: The tube ring mounting plate included with the Atlas
EQ-G includes four optical axis offset adjustment screws;
these are the socket head cap screws located at each cor-
ner of the mounting plate. These adjustment screws will be
explained further in Appendix A. For now, confirm that all four
adjustment screws are sufficiently unthreaded so that the
ends of their threaded shafts are flush with the top surface of
the tube ring mounting plate.
Note: The optical axis offset adjustment screws should be
oriented so that the threaded shaft extends upward through
the top surface of the tube ring mounting plate. If the tube
ring mounting plate arrives with the optical axis offset screws
installed backwards, reverse their orientation before proceed-
ing (Figure 3).
2. Loosen the black mounting plate lock knobs on the top of
the equatorial mount. Place the mounting plate, with the
tube rings attached, in the slot on top of the equatorial
mount. Position the mounting plate so that it is centered in
the slot. Re-tighten the mounting plate lock knobs until the
plate is secure.
3. Open the tube rings and lay the telescope optical tube in
the rings at about the midpoint of the tube’s length. Rotate
the tube so that the focuser is at a convenient height for
viewing. Close the tube rings and tighten them.
Note: The Atlas EQ-G mount is very heavy. Alone it weighs 54
lbs. With a large optical tube and counterweights it can easily
weigh over 100 lbs. Keep this in mind when moving the tele-
scope even small distances, and use assistance when need-
ed. It is best to remove the optical tube and counterweights
when moving the mount.
Note: Some telescope optical tubes (specifically Schmidt-
Cassegrains and Maksutov-Cassegrains) have a mounting
plate connected directly to the tube. For these telescopes,
optional tube rings are not required. Simply follow step 2
(above) to connect the telescope to the mount.
5. Balancing a Telescope
To ensure smooth movement of a telescope on both axes of
the equatorial mount, it is imperative that the optical tube is
properly balanced. We will first balance the telescope with
respect to the right ascension (R.A.) axis, then the declination
(Dec.) axis.
1. Keeping one hand on the telescope optical tube, loosen
the R.A. lock lever. Make sure the Dec. lock lever is locked,
for now. The telescope should now be able to rotate freely
about the right ascension axis. Rotate it until the counter-
weight shaft is parallel to the ground (i.e., horizontal).
Figure 3. The tube ring mounting plate.
Optical axis offset
adjustment screws
Flat washer
Lock washer
Tube ring
attachment screw

5
2. Now loosen both counterweight lock knobs and slide the
weights along the shaft until they exactly counterbalance
the telescope (Figure 4a). That’s the point at which the
shaft remains horizontal even when you let go with both
hands (Figure 4b). If the telescope refuses to balance
than you have either too much or too little counterweight.
Remove a counterweight, or add optional counterweights
if needed.
3. Retighten the counterweight lock knobs. The telescope is
now balanced on the right ascension axis.
4. To balance the telescope on the declination axis, first tight-
en the R.A. lock lever, with the counterweight shaft still in
the horizontal position.
5. With one hand on the telescope optical tube, loosen the
Dec. lock lever. The telescope should now be able to rotate
freely about the declination axis.
6. Loosen the knurled ring clamps on the tube rings 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) (Figure 4c).
7. Position the telescope in the tube rings so it remains hori-
zontal when you carefully let go with both hands. This is
the balance point for the optical tube with respect to the
Dec. axis (Figure 4d).
8. Retighten the knurled ring clamps.
The telescope is now balanced on both axes. When you loos-
en the lock lever on one or both axes and manually point the
telescope, it should move without resistance and should not
drift from where you point it.
6. 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 5) is designed to
compensate for that motion, allowing you to easily “track” the
movement of astronomical objects, thereby keeping them
from drifting out of your 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 the built in motor drive. But
first the R.A. axis of the mount must be aligned with the Earth’s
rotational (polar) axis—a process called polar alignment.
Figure 4a-d. Proper operation of the equatorial mount requires
that the telescope tube be balanced on the R.A. and Dec. axes. (a)
With the R.A. lock lever released, slide the counterweights down
the counterweight shaft until they just counterbalance the telescope
tube. (b) When you let go with both hands, the tube should not drift
up or down. (c) With the Dec. lock lever 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.
a. b.
c. d.
Figure 6. 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).
Big Dipper
(in Ursa Major)
Little Dipper
(in Ursa Minor)
Cassiopeia
N.C.P.
Pointer
Stars
Polaris
Figure 5. The Atlas EQ-G mount.
Dec. lock lever
(not shown)
Front opening
R.A. lock lever
Polar axis
finder scope
Latitude scale
Latitude
adjustment L-bolts
Azimuth
adjustment
knobs (2)
Declination (Dec) axis
Right Ascension
(R.A.) axis

6
Polar Alignment
For Northern Hemisphere observers, approximate polar align-
ment is achieved by pointing the mount’s right ascension axis
at the North Star, or Polaris. It lies within 1° of the north celes-
tial pole (NCP), which is an extension of the Earth’s rotational
axis out into space. Stars in the Northern Hemisphere appear
to revolve around the NCP.
To find Polaris in the sky, look north and locate the pattern
of the Big Dipper (Figure 6). 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 align-
ment is sufficient.
1. Level the equatorial mount by adjusting the length of the
three tripod legs.
2. There are two latitude adjustment L-bolts (see Figure 5);
loosen one while tightening the other. By doing this you
will adjust the latitude of the mount. Continue adjusting the
mount until the pointer on the latitude scale is set at the
latitude of your observing site. If you don’t know your lati-
tude, consult a geographical atlas to find it. For example,
if your latitude is 35° North, set the pointer to 35. The lati-
tude setting should not have to be adjusted again unless
you move to a different viewing location some distance
away.
3. Loosen the Dec. lock lever and rotate the telescope’s opti-
cal tube until it is parallel with the right ascension axis, as
it is in Figure 5.
4. Move the tripod so the telescope tube and right ascen-
sion axis point roughly at Polaris. If you cannot see Polaris
directly from your observing site, consult a compass and
rotate the tripod so the telescope points north.
The equatorial mount is now polar aligned for casual observ-
ing. More precise polar alignment is recommended for
astrophotography. For this we recommend using the polar
axis finder scope.
From this point on in your observing session, you should not
make any further adjustments to the latitude of the mount,
nor should you move the tripod. Doing so will undo the polar
alignment. The telescope should be moved only about its R.A.
and Dec. axes.
The Polar Axis Finder Scope
The Atlas EQ-G mount comes with a polar axis finder scope
(Figure 7) housed inside the right ascension axis of the
mount. When properly aligned and used, it makes accurate
polar alignment quick and easy to do. Unthread the cover at
the rear of the mount’s right ascension axis and remove the
cap on the front opening of the equatorial mount (Figure 5) to
view through the polar axis finder scope.
Alignment of the Polar Axis Finder Scope
1. Loosen the Dec. lock lever and rotate the optical tube about
the declination axis until you have a clear view through the
polar axis finder scope (Figure 8). Tighten the Dec. lock
lever.
2. Look through the polar finder at a distant object (during
the day) and center it in the crosshairs. You may need to
adjust the latitude adjustment L-bolts and the tripod posi-
tion to do this. Focus the polar finder by rotating the eye-
piece.
3. Rotate the mount 180° about the R.A. axis. It may be con-
venient to remove the counterweights and optical tube
before doing this.
4. Look through the polar finder again. Is the object being
viewed still centered on the crosshairs? If it is, then no
further adjustment is necessary. If not, then look through
the polar finder while rotating the mount about the R.A.
axis. You will notice that the object you have previously
centered moves in a circular path. Use the three alignment
set-screws on the polar axis finder (Figure 7) to redirect
the crosshairs of the polar finder to the apparent center of
this circular path.
5. Repeat this procedure until the position that the crosshairs
point to does not rotate off-center when the mount is rotat-
ed in R.A.
Figure 8. The optical tube must be rotated about the declination
axis in order to view through the polar axis finder.
Figure 7. The polar axis finder scope.
Eyepiece
focus ring
Alignment
setscrew (3)
Focus
lock ring
Objective
lens

7
The polar axis finder scope is now ready to be used. When not
in use, replace the plastic protective cover to prevent the polar
finder from getting bumped.
Using the Polar Axis Finder Scope
The reticle of the polar axis finder scope for the Atlas EQ-G
has a tiny star map printed on it that makes precise polar align-
ment quick and easy. To polar align the mount using the polar
axis finder scope, follow these instructions:
1. Approximately polar-align the mount as outlined in the pro-
cedure above.
2. Loosen the Dec. lock lever and rotate the optical tube on
the declination axis so the tube is at a 90° angle to the right
ascension axis (Figure 8). Tighten the Dec. lock lever.
3. Focus the polar finder by rotating the eyepiece. Now, sight
Polaris in the polar axis finder scope. If you have followed
the approximate polar alignment procedure accurately,
Polaris will probably be within the field of view. If not, move
the tripod left-to-right, and adjust the latitude up-and down
until Polaris is somewhere within the field of view of the
polar axis finder scope.
4. The mount has a built-in illuminator that allows you to see
the reticle pattern in the polar axis finder scope at night.
Simply turn on the power switch on the Atlas EQ-G mount
(see “Powering the Atlas EQ-G Mount”) and the polar axis
finder scope reticle will be illuminated. Note the constel-
lation Cassiopeia and the Big Dipper in the reticle. They
do not appear in scale, but they indicate the general posi-
tions of Cassiopeia and the Big Dipper relative to the north
celestial pole (which is indicated by the cross at the cen-
ter of the reticle). Rotate the reticle so the constellations
depicted match their current orientation in the sky when
viewed with the naked eye. To do this, release the R.A. lock
lever and rotate the main telescope around the R.A. axis
until the reticle is oriented with sky. For larger optical tubes,
you may need to remove the tube from the mount to pre-
vent it from bumping into the mount. Once the reticle is cor-
rectly oriented, use the right ascension lock lever to secure
the mount’s position.
5. Now use the azimuth adjustment knobs (Figure 2) and the
latitude adjustment L-bolts (Figure 5) on the mount to posi-
tion the star Polaris inside the tiny circle marked “Polaris”
on the finder’s reticle.You must first loosen the knob under-
neath the equatorial mount on the center support shaft to
use the azimuth adjustment knobs. Once Polaris is properly
positioned within the reticle, you are precisely polar aligned.
Retighten the knob underneath the equatorial mount.
If you do not have a clear view of Polaris from your observing
site, you will not be able to use the polar-axis finder to pre-
cisely polar align the telescope.
Note: 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 telescope should be moved only
about its right ascension and declination axes.
Additional Note Regarding Focusing the Polar Axis
Finder Scope
The polar axis finder scope is normally focused by simple rota-
tion of the eyepiece focus ring. However, if after adjusting the
focus ring you find that the image of the reticle is sharp, but
the stars are out of focus, then you must adjust the focus of
the polar axis finder’s objective lens. To do this, first remove
the polar axis finder from the mount by unthreading it. Look
through the polar axis finder at a star (at night) or distant object
at least 1/4 mile away (during daylight). Use the eyepiece focus
ring to bring the reticle into sharp focus. Now, loosen the focus
lock ring (Figure 7) and thread the entire objective end of the
finder inward or outward until images appear sharp. Re-tighten
the focus lock ring. Once the polar axis finder’s objective lens
is focused, it should not need to be adjusted again.
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?
DO NOT make any adjustment to the latitude adjustment L-
bolts. That will spoil 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 lever and rotate the tele-
scope on the right ascension axis until the counterweight shaft
is horizontal (parallel to the ground). Then loosen the Dec. lock
lever and rotate the telescope until it is pointing straight over-
head. The counterweight shaft is still horizontal. Then retighten
both lock levers.
Figure 9a-d. These illustrations show 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 has been moved on the its R.A. and Dec. axes.
a. b. c. d.

8
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 counterweights down as pictured in Figure 1. Again,
you have to rotate the scope in right ascension so that the
counterweight shaft is positioned horizontally. Then rotate the
scope in declination so it points to where you want it near the
horizon.
To point the telescope directly south, the counterweight shaft
should again be horizontal. Then you simply rotate the scope
on the declination axis until it points in the south direction.
To point the telescope to the east or west, or in other directions,
you rotate the telescope on its right ascension and declina-
tion axes. Depending on the altitude of the object you want to
observe, the counterweight shaft will be oriented somewhere
between vertical and horizontal.
Figure 9 illustrates how the telescope will look when pointed
at the four cardinal directions: north (Figure 9a), south (Figure
9b), east (Figure 9c) and west (Figure 9d).
The key things to remember when pointing the telescope are
that a) you only move it in right ascension and declination, 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!
7. The Atlas EQ-G Dual-Axis
Controller
The Atlas EQ-G with dual-axis hand controller will track any
celestial object as the Earth rotates.You can also use the con-
troller’s directional buttons to center objects within your tele-
scope’s finderscope or eyepiece. For imaging purposes, the
controller provides several guide speed rates so a camera can
be accurately guided during a long exposure.
Attaching the Dual-Axis Controller
The dual-axis controller has a cable with a large, serial con-
nector (DB-9) on one end. Plug the serial connector into the
jack on the faceplate of the mount (Figure 9.1). Use the captive
screws to secure the serial connector in place.
The nylon hook-and-loop strips have been provided so the
dual-axis hand controller can be placed in a convenient posi-
tion on the mount when not in use. Place the “hooks” strip on
the back of the dual-axis hand controller, and the “loops” strip
on the mount in a convenient location. Make certain the loca-
tion of the strip on the mount will not cause the dual-axis hand
controller to interfere with the motions of the mount or tele-
scope being used.
You can reduce the chances of getting your hand controller,
power supply, or other cables tangled during use of the Atlas
EQ-G by using the included wire clip. The clip also prevents
mechanical strain on the cord when being used. The wireclip is
adhesive backed for easy attachment to any convenient loca-
tion on the mount.
Powering the Atlas EQ-G Mount
The Atlas EQ-G should be powered by a 12V DC power sup-
ply (tip-positive) capable of producing continuous current
with a minimum of 2 amps. We recommend using a portable
rechargeable battery, like the Dynamo or Dynamo Pro avail-
able from Orion.
If you are using a portable battery like the Orion Dynamo, use
the supplied 12V DC power cable (male cigarette lighter plug
on one end, standard 12V DC power plug on the other end) to
connect the battery to the 12V DC power jack on the faceplate
of the mount (Figure 9.1). Make sure the Dynamo’s power
switch is in the “on” position after connecting.
Functions of the Dual-Axis Hand Controller
There are three main categories of control buttons on the dual-
axis controller (Figure 9.2).
1. Speed buttons
2. Directional buttons
3. Set button
The dual-axis hand controller is equipped with a red LED light
in each button to indicate operation. An individual button’s LED
will illuminate when the button is pressed. If a button combina-
tion is entered, all LEDs will illuminate to indicate a successful
operation.
Speed Buttons
The three buttons located near the top of the dual-axis hand
controller (Guide, Slow, and Fast) are used to set the slewing
and guiding speed of the mount.
Directional Buttons
The directional buttons allow complete control of the mounted
telescope’s position during slewing or tracking. The Left and
Right directional buttons control movements about the right
ascension (R.A.). axis. The Up and Down directional buttons
control movements about the declination (Dec.) axis.
Set Button
The Set button is used to set the dual-axis hand controller to
operate in either Northern or Southern hemisphere locations.
Note: The Go button is not used in normal operation of the
dual-axis controller.
Tracking Objects with the Dual-Axis Hand
Controller
In order for your Atlas EQ-G mount to accurately track celestial
objects as they appear to migrate across the night sky, your
mount must be properly polar aligned. For more details on
polar alignment, please consult section 6 of this manual.
Once the power switch is turned on, the dual-axis controller
begins to track by rotating the R.A. axis motor at the default
(sidereal) rate. The Dec. axis motor will not rotate. As long as
the mount has been properly polar aligned, it should not be
necessary to adjust the Dec. axis for accurate tracking. If you
notice a lack of tracking precision at the default (sidereal) rate,

9
consult section 6 of this manual and attempt to polar align the
mount more accurately.
Tracking can be deactivated or activated at any time the Atlas
EQ-G mount is receiving power. In order to deactivate tracking,
simply press and hold the Guide button then press the Slow
button on the controller. Pressing the same button combination
will reactivate tracking at the default (sidereal) rate.
There are three tracking rates used by the dual-axis control-
ler:
Sidereal rate tracking is the default tracking rate for the Atlas
EQ-G mount. Celestial objects are tracked using this rate
which is equivalent to the rate of the Earth’s rotation.
Solar rate tracking is used to track the Sun over a long period
of time. Solar rate tracking is activated by pressing and holding
the Slow speed button, then the Right directional button.
Warning: Never look directly at the Sun through your tele-
scope or its finder scope, even for an instant, without a
professionally made solar filter that completely covers the
front aperture of the instrument, or permanent eye dam-
age could result.Young children should use this telescope
only with adult supervision.
Lunar rate tracking is used to track the Moon at its rate of
apparent motion across the sky. Lunar rate tracking is activat-
ed by pressing and holding the Slow button, then the Down
directional button.
Note: Solar and Lunar tracking rates can only be used when
the Atlas EQ-G has tracking activated. If tracking is deacti-
vated, you must first activate tracking by holding the Guide
button then pressing the Slow button.
Setting the Slewing Speed
In order to conveniently center an object in your telescope’s
finderscope or eyepiece, you can set the speed rate at which
the motors slew (move) the telescope when the directional
buttons are pressed. The three speed buttons located near the
top of the hand controller are used to set the slewing rates of
the mount.
The slewing speed buttons each have two different speeds
assigned to them. The slewing speed employed is dependent
on whether or not the dual-axis controller has tracking activat-
ed or deactivated (by holding the Guide button then pressing
the Slow button).
With tracking activated, the Guide button will slew the Atlas
EQ-G mount at a very slow speed equal to 1.5x sidereal rate.
This speed rate will generally be used to guide a telescope
while imaging with a camera. You can also change the Guide
button speed rate to be slightly faster or slower (see “Setting
the Guiding Speed”). If tracking is deactivated, pressing the
Guide button will set the Atlas EQ-G to slew at 32x sidereal
rate; this speed is too fast for guiding during imaging.
By pressing the Slow button with tracking activated, the Atlas
EQ-G will slew at 4x sidereal rate. With tracking deactivated,
pressing the Slow button will set the Atlas EQ-G mount to slew
at 64x sidereal rate.
With tracking activated, the Fast button will set the Atlas EQ-G
mount to slew at 8x sidereal rate. If tracking is not activated,
pressing the Fast button will set the Atlas EQ-G to slew at
800x sidereal rate; this is a very fast speed that can be used to
slew the mount from object to object across the sky.
Figure 9-1. Atlas EQ-G mount faceplate.
Power indicator light
12V DC
power jack Power
switch
Autoguider
modular
jack
Hand controller serial jack
Figure 9-2. The Atlas EQ-G Dual-Axis hand controller
Speed
buttons
Directional
buttons
Set button

10
Changing the Guiding Speed
The dual-axis hand controller provides 4 different guiding
speed settings: 2x, 1.75x, 1.5x (default), and 1.25x sidereal
rate. If you change the guiding speed from the default setting
of 1.5x sidereal rate, the controller will guide at the chosen
speed until another guiding speed is selected.
In order to set the guiding speed of your Atlas EQ-G, use the
button following button combinations:
 •2xsiderealrate: HoldtheFast button, then press
the Up directional button.
 •1.75xsiderealrate: HoldtheFast button, then press
the Left directional button.
 •1.5xsiderealrate: HoldtheFast button, then press
the Right directional button.
 •1.25xsiderealrate: HoldtheFast button, then press
the Down directional button.
Reversing the Directional Buttons
Celestial objects appear to move through the sky differently
when viewed through telescopes and/or accessories of dif-
ferent designs. For example, if an object viewed through a
refractor appears to migrate towards the left-hand side of an
eyepiece’s field of view, it will appear to migrate towards the
right-hand side of an eyepiece’s field of view in a reflector
telescope.
In order to make viewing and tracking objects convenient,
regardless of telescope design, the dual-axis controller fea-
tures a “reverse” function which reverses the direction of the
hand controller’s directional buttons. This way you can match
the directional button to the way the object actually moves in
the telescope eyepiece.
To reverse the direction of the Left and Right directional but-
tons, press and hold the Slow speed button then press the
Left directional button. To reverse the direction of the Up and
Down directional buttons, press and hold the Slow button
then press the Up directional button.
Once you have reversed the directional buttons, the dual-axis
controller will save the reversed settings until it they are man-
ually changed again. Turning the power off will not affect the
directional button setting last entered.
Northern or Southern Hemisphere Operation
The dual-axis hand controller is capable of operating in either
Northern or Southern Hemisphere viewing locations.The sys-
tem is set up for Northern Hemisphere locations by default, so
if you are viewing from a Northern Hemisphere location, it is
not necessary to make any setting changes.
For the dual-axis controller to properly track celestial objects
in the Southern Hemisphere, press and hold the Down direc-
tional button and then press the Set button while powering
on the mount. Release the Set button after the mount has
successfully powered on and the Guide button begins flash-
ing. The controller will now operate properly in the Southern
Hemisphere. You can switch back to Northern Hemisphere
mode by using the same button combination. As long as the
controller is operating in Southern Hemisphere mode, the Set
button will illuminate.
Power Conservation
In the interest of conserving the amount of power drawn by the
Atlas EQ-G mount, the Dec. motor will enter a “sleep” mode if
left idle for a period of 15 seconds. In “sleep” mode, the Dec.
motor stops completely and the amount of used power drops
by about 40%. To reactivate the Dec. motor, press the Up or
Down directional button.
Upgrading your Atlas EQ-G
While the dual-axis hand controller provides many useful
functions such as celestial object tracking and motorized
motion control, there is a GoTo hand controller for the Atlas
EQ-G available from Orion. The features and functions of the
GoTo hand controller are explained in the following section.
If you are interested in upgrading your Atlas EQ-G to a GoTo
system, call our Customer Service department at 800-676-
1343 or visit our website at www.OrionTelescopes.com for
more information.
8. The Atlas EQ-G GoTo
Hand Controller
The Atlas EQ-G mount equipped with the GoTo hand control-
ler provides easy, computerized location of thousands of night
sky objects such as planets, nebulae, star clusters, galaxies,
and more for viewing through your telescope. The GoTo hand
controller and internal dual-axis motors allow you to automati-
cally point your telescope at a specific object, or tour the skies
with pushbutton simplicity. The user-friendly menu allows
automatic slewing to over 13,400 objects. Even inexperienced
astronomers will find themselves quickly mastering the vari-
ety of features the GoTo hand controller offers in just a few
observing sessions.