Orion EQ-3M User manual

Welcome to a new world of adventure. The Orion EQ-3M
Dual-Axis DC Motor Drive System allows convenient hands-
free sidereal tracking of the night sky for telescopes, like the
SkyWatcher 120, that utilize the Orion EQ-3 Equatorial Mount.
The motor drive system is also a necessary component for
doing long-exposure astrophotography. The electronic hand
controller allows positional corrections to be made to both the
right ascension (R.A.) and declination (Dec.) axes of the
mount during an astrophotographic exposure.
1. Parts List
1 R.A. motor assembly
1 Dec. motor assembly (with white nylon gear wheel)
1 Dec. clutch assembly
1 Hand controller
1 Battery pack
1 Socket-head cap screw
1 Washer
1 5mm Allen wrench
1 4mm Allen wrench
1 2mm Allen wrench
2. Installing the R.A. Motor Assembly
1. When facing the front of the mount, the R.A. slow-motion
control cable should be mounted to the right end of the
R.A. worm gear shaft (Figure 1). If it is mounted on the left
end, remove it, and reinstall it on the right end of the
shaft.
2. The R.A. motor is the one with the chrome-colored bracket
and black cylindrical coupling, pictured in Figure 2. Using
the provided 2mm Allen wrench, loosen the socket-head
setscrew on the end of the coupling).
Orion®EQ-3M Dual-Axis DC Motor Drive System
#7828
Figure 1
Figure 2
Left end of
R.A. worm
gear shaft
Dec. worm gear
assembly
Right end
of R.A.
worm gear
shaft
Setscrew
on end of
R.A. motor
drive coupling
IN 134 Rev. B 02/09

3. Use the provided 4mm Allen wrench to remove the socket-
head bolt on the left side of the mount (Figure 3).
4. Orient the motor so that the drive coupling slips over the
left end of the R.A. worm gear shaft. Now, attach the
motor to the mount by inserting the socket-head bolt
through the slot in the motor’s bracket, and rethreading it
into the mount.
5. Tighten the socket-head setscrew on the end of the
motor’s drive coupling. The setscrew should seat into the
groove on the end of the worm gear shaft. You may need
to rotate the worm gear, using the R.A. slow-motion con-
trol cable, for the setscrew and the groove to line up. You
may also need to adjust the drive coupling to position the
setscrew over the groove; this is done by loosening the
setscrew on the drive coupling that is closest to the motor.
Once both setscrews are tightened, the R.A. motor is
engaged. When the motor is engaged, never, under any
circumstances, should you use the R.A. slow-motion con-
trol cable! If you want to use it, first loosen the socket-head
setscrew on the end of the coupling to disengage the
motor drive.
The motor is now properly installed on the EQ-3 mount, and
should appear as in Figure 4.
3. Installing the Declination Motor Assembly
1. Release the Dec. lock lever, and rotate the mount about
the Dec. axis until the Dec. worm gear assembly is on the
right side when facing the mount, as in Figure 1. Retighten
the Dec. lock lever. If the Dec. slow-motion control cable
is attached to the front end of the Dec. worm gear shaft,
it will need to be removed, for now.
2. Attach the Dec. clutch assembly to the front end of the
Dec. worm gear shaft. This is done by first loosening the
setscrew on the brass portion of the clutch assembly with
the 2mm Allen wrench. Now, slide the clutch assembly
over the front end of the Dec. worm gear (Figure 5).
Position the clutch assembly so that the setscrew lines up
with the groove on the end of the worm gear. Tighten the
Figure 3
Figure 5
Figure 4
Socket-
head bolt
Head
casting
flange
Dec.
clutch
assembly

setscrew so it seats into the groove and makes a firm
connection.
3. Attach the Dec. motor assembly to the flange on the head
casting of the mount (refer to Figure 5) with the socket-
head cap screw and washer. First, position the motor
underneath the flange so that the gear on the motor and
the gear on the clutch assembly mesh. Next, insert the
cap screw with washer attached down through the slot in
the head casting flange and thread it into the insert on the
Dec. motor housing. Use the 5mm Allen wrench to do this.
While threading the cap screw into the housing, hold the
Dec. motor assembly in position, so that when the screw
is fully tightened, the gears make a good connection
(Figure 6).
4. If you have removed the Dec. slow-motion control cable, it
can now be replaced on either the front shaft of the clutch
assembly or the rear end of the Dec. worm gear shaft.
5. When the knurled chrome section of the clutch assembly
is rotated clockwise until tight, the Dec. motor is engaged.
Never use the Dec. slow-motion control cable when the
Dec. motor is engaged or you may damage the motor. To
use the Dec. slow-motion control cable, first rotate the
chrome bushing of the clutch assembly counter-clockwise
by a turn.
The Dec. motor is now properly installed on the EQ-3 mount,
and should appear as in Figure 7.
4. Operation
Insert four D-cell batteries into the battery pack. Orient the
batteries as indicated on the white plastic battery holder.
Connect the end of the battery pack’s power cord to the DC
power input on the hand controller.
There are two white cords that are permanently connected to
the hand controller. The printing on the bottom of the hand
controller’s front panel indicates the R.A. cord and the Dec.
cord. Connect the modular connector on the end of the R.A.
cord to the receptacle on the R.A. motor assembly, and con-
nect the end of the Dec. cord to the receptacle on the Dec.
motor assembly.
For the motor drive system to track the motion of the night
sky properly, the equatorial mount must be polar aligned.
This involves aligning the R.A. axis of the mount so it is paral-
lel to the Earth’s axis of rotation (polar axis). Consult the
manual that came with your equatorial mount for details on
how to polar align it.
When observing in the Northern Hemisphere, the N/S switch on
the hand controller should be in the “N” position. For the
Southern Hemisphere, it should be in the “S” position.
Make sure the motors are engaged, and turn the power
switch on the hand controller to the “ON” position. The LED
in the center of the hand controller should be shining green.
If properly polar aligned, the mount will now be tracking the
motion of the night sky, and the telescope should hold any
astronomical object in its eyepiece steady over time.
To move your telescope to a new object, loosen both the R.A.
and Dec. lock levers and move the telescope until it is point-
ed in the general direction of the object you wish to view.
Retighten the R.A. and Dec. lock levers. Now, disengage
both motors and use the R.A. and Dec. slow-motion control
cables to center the object in the eyepiece’s field of view.
Re-engage the motors, and the motor drive system will keep
the object centered over time. Remember, never use the
Figure 6
Figure 7

Providing Exceptional Consumer Optical Products Since 1975
Customer Support [phone]
E-mail: [email protected]
Corporate Offices [phone]
89 Hangar Way, Watsonville, CA 95076
One-Year Limited Warranty
This Orion EQ3M Dual-Axis DC Motor Drive System is warranted against defects in materials or work-
manship 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, con-
tact: Customer Service Department, Orion Telescopes & Binoculars, 89 Hangar Way, Watsonville, CA
95076; [phone].
slow-motion control cables when the motors are engaged or
you could permanently damage the motors.
There are four pushbuttons on the hand controller. When the
motors are engaged the left and right buttons move the
mount about its R.A. axis, and the up and down buttons
move the mount about its Dec. axis. The rate of speed the
mount moves at is determined by the rate switch at the top
right of the hand controller. If the switch is at the 2x position,
the mount will move at two times the sidereal rate when any
of the buttons are pushed. Similarly, if the switch is at the 4x
or 8x position, the mount will move at four times or eight
times sidereal when a button is pushed. If no buttons are
pushed, the R.A. motor will turn the R.A. axis at sidereal rate
to track the motion of the night sky.
The 2x sidereal rate is the best setting for making guiding
corrections during long-exposure astrophotography. The 4x
and 8x rates are best for centering an object within the tele-
scope’s eyepiece.
Note that whenever any of the four buttons on the hand con-
troller are pressed, the LED in the center of the controller will
shine red; when the button is released, the LED will be green
again. Also, when the LED starts to blink at a constant rate, it’s
time to change the batteries in the battery pack.
6. Specifications
EQ-3M
Guiding rate: ±100% sidereal
Centering rates: ±400% sidereal , ±800% sidereal
Power requirement: 6V DC
Battery type: four D-cells
Northern or Southern Hemisphere operation
DC stepper motors
Externally clutched