Orion HDX110 User manual

Orion HDX110 EQ-G Equatorial
GoTo Mount
#10011 HDX110 Mount with Tripod Pier
#10044 HDX110 Mount only
IN 502 Rev. B 06/14
INSTRUCTION MANUAL
Figure 1. The HDX110 EQ-G mount with Tripod Pier
Customer Support:
www.OrionTelescopes.com/contactus
Corporate Offices:
89 Hangar Way, Watsonville CA 95076 - USA
Providing Exceptional Consumer Optical Products Since 1975
Copyright © 2014 Orion Telescopes & Binoculars
All Rights Reserved. No part of this product instruction or any of its contents may be reproduced, copied, modified or adapted,
without the prior written consent of Orion Telescopes & Binoculars.

2
Figure 2. Contents of the Equatorial Mount box
EQ Mount
SNAP
(camera) cable
12V DC
power cable Hand
controller
cable
SynScan
hand
controller
Azimuth
lock bolts
Azimuth
adjustement
knobs
Counterweight
shaft
RS-232 cable
Jackscrew
handle
Table of Contents
1. Unpacking ........................... 3
1.1. Unpacking .................................3
1.2 Parts List ..................................3
2. Setting Up the HDX110 EQ-G Mount ...... 4
2.1 Setting Up the Tripod Pier. . . . . . . . . . . . . . . . . . . . . . 4
2.2 Attaching the Mount to the Tripod Pier ............6
2.3 Leveling the Mount ...........................6
2.4 Attaching the Counterweight Shaft and
Counterweights ................................7
2.5 Setting the Latitude ..........................8
2.6 Adjusting the Azimuth.........................8
3. Installing a Telescope on the Mount ...... 8
3.1 Installing the Telescope .......................8
3.2 Balancing the Telescope.......................8
4. Polar Alignment ....................... 9
4.1 Preparing the Mount for Polar Alignment ..........9
4.2 Polar Alignment Using the SynScan Hand Controller 9
4.3 Polar Alignment Using the Optional Polar-Axis Scope 9
5. Drive Panel Interface .................. 10
5.1 Drive Panel................................10
5.2 Panel Interface Components ..................10
5.3 Pinout of the Interfaces (Figure 19) .............10
5.4 Connecting the SynScan GoTo Hand Controller ...10
5.5 Power Supply Requirements ..................11
6. Other HDX110 EQ-G Features .......... 11
6.1 Auto-Home Function ........................11
6.2 Auxiliary Encoder Function....................11
6.3 Permanent Periodic Error Correction ............11
6.4 Batch Exposure Function .....................11
7. Care of Your HDX110 EQ-G Mount ....... 12
Addendum: Adusting the Declination Axis
Backlash.............................. 12
Specifications ......................... 14

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Congratulations on your purchase of the Orion HDX110 EQ-G GoTo Mount! This high-performance
equatorial mount with an instrument payload capacity of 110 lbs. and typically +/- 3 arc-second tracking
accuracy delivers the stability and precision needed for serious visual and imaging work with medium-
size to large telescopes. These instructions will help you set up and properly use your new mount.
Please read them over thoroughly before getting started.
1. Unpacking
1.1. Unpacking
The entire mount including tripod pier (#10011) is packaged in
four boxes, one containing the equatorial head, hand control-
ler, and cables (Figure 2); one containing the pier tripod and
leveling pads (Figure 3); and two boxes containing one 22-lb.
counterweight each (Figure 4). Use care in opening the boxes.
If you purchased the #10044 HDX110 equatorial head only, it
comes in one box (Figure 2).
We recommend keeping all of the original packaging after
the mount is unpacked. In the event that the mount has to be
returned to Orion for warranty repair, having the proper pack-
aging will ensure that the mount will survive the journey intact.
Make sure all the parts in the Parts List are present. Be sure
to check the boxes thoroughly, as some parts are small. If
anything appears to be missing or damaged, immediately call
Orion Customer Support (800-676-1343) or email support@
telescope.com for assistance.
1.2 Parts List
Equatorial Mount Box (Figure 2)
Qty Item
1 HDX110 equatorial head
1 Counterweight shaft
1 DC power cable
1 SynScan hand controller
1 Hand controller coil cable
1 RS-232 serial cable
1 Shutter release cable (select Canon EOS)
1 Jackscrew handle
Tripod
pier
Leveling pads
Wing nuts
Washers
Combination
wrench
Hand controller bracket Bracket mounting
screws
2.5mm
Allen wrench
Slide
blocks
Bolts
Figure 3. Contents of the Tripod Pier box (included with #10011)
WARNING: Do NOT look at the Sun without a
professionally made solar filter on the telescope;
serious eye damage may result if you look at the
Sun with any unfiltered optical instrument. Do
not leave the telescope unsupervised around
children. Always cover the lenses when leaving
the telescope in direct sunlight.

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1 6mm Allen wrench
1 Cable clamp (not shown)
1 Instruction manual – HDX110 EQ-G
1 Instruction manual – SynScan
Tripod Pier Box (Figure 3)
1 Tripod pier
3 Leveling pads
1 Bracket for SynScan controller
2 M3 Allen screws (for SynScan bracket)
1 2.5mm Allen wrench
3 Slide blocks
3 Hex head bolts
3 Washers
3 Wing nuts
1 Combination wrench (19mm)
Counterweight box (Figure 4)
1 Counterweight (22 lbs.), with lock knob
Counterweight box
1 Counterweight (22 lbs.), with lock knob
CAUTION: Never set the equatorial head down such
that the motor covers or encoder/gear housings bear
the weight of the mount, as this could damage those
components and the hardware inside them. If you need
to set the mount down on the ground or other flat sur-
face, always orient the mount in the “upright” position in
which only the bottom plate contacts the surface.
2. Setting Up the HDX110
EQ-G Mount
2.1 Setting Up the Tripod Pier
The HDX110’s tripod pier is heavy and thus should be handled
with due caution.
1. Spread the tripod legs outward as far as they will go
(Figure 5a).
2. Loosen the two hex nuts on the pier clamp with the
included combination wrench (Figure 5b). Loosen them
alternately, a little at a time. Be aware that the pier could
drop suddenly if the clamp becomes loose enough. To
prevent this, we recommend keeping some positive,
upward pressure on the pier with one hand while
loosening the nuts with the other.
Figure 5. (a) Once the tripod legs are spread all the way
outward, (b) the pier height can be adjusted by loosening
the two hex nuts on the pier clamp.
Figure 4. Two 22-lb. counterweights (included with #10011)
a.
b.
Metal post
Pier
Gap
Pier clamp
Primary
locking
knob
Hex
nuts
align

5
3. Once the clamp is loosened, rotate the pier in the clamp
until the post on the top plate is roughly aligned with the
gap in the clamp (Figure 5b).
4. Slide the pier up or down in the clamp to the desired
height, then tighten the two hex nuts on the clamp.
Tighten them in an alternate manner a little bit at a time
to avoid damage to the clamp. Do not overtighten the two
nuts!
5. Clamp the three tripod support braces with the slide
blocks and associated hardware as shown in Figure 6.
Tighten the wing nuts.
6. If your surface is not level, use the leveling pads
underneath the tripod legs. Place a leveling pad under
each tripod foot by lifting each leg one at a time and
sliding a leveler pad under it. Place the tip of the foot in
the center depression of the pad (Figure 7).
7. While the HDX110’s equatorial head has a built-in
circular bubble level, if you wish to level the tripod before
adding the weight of the head on top of it, you will need
to purchase a circular bubble level from a hardware store.
8. To extend the leveling screw, turn it counterclockwise.
Tighten the lock rings on all three leveling pads once the
tripod is level (Figure 7).
Figure 6. Clamp the tripod support braces with the included
hardware as shown.
Washer
Wing nut
Slide block
Tripod
support
braces
Tripod
foot
Leveling
screw
Leveling
pad
Lock
ring
Bolt
Figure 7. Leveling pads placed under the tripod feet help
level the mount.

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9. Attach the hand controller bracket to the two posts with
the included screws (Figure 8).
2.2 Attaching the Mount to the Tripod Pier
1. Lift the mount out of the case with both hands, using the
handles attached to the mount.
2. Before attaching the mount, if the azimuth adjustment
knobs are installed, make sure there is a wide gap
between the bolts (Figure 9).
3. Then place the mount on the tripod pier, aligning the
metal post on the top of the pier with the gap between
the two azimuth adjustment knobs (Figure 10).
4. Once the mount is seated on the pier, turn the primary
locking knob clockwise. That turns the threaded center
post on the pier, which threads into the hole on the
bottom center of the mount. Turn the knob until tight.
5. Install the two azimuth locking bolts with washers; do not
tighten them completely yet (Figure 11).
6. Install the two azimuth adjustment knobs if they are not
already installed. Thread them in as far as they will go.
Refer to Figure 12.
7. Install the two altitude locking bolts if they are not already
installed. Do not tighten them completely.
8. Unthread and remove one of the two ball-head screws
from the end of the jackscrew handle and slide the
jackscrew handle into the hole in the altitude jackscrew.
Then replace the ball-head screw.
2.3 Leveling the Mount
The HDX110 mount has a built-in bubble level, shown in
Figure 12, making it easy to level the mount using the three
leveling pads that you placed under the tripod legs. It will be
easier to do this now, before attaching the counterweights and
telescope.
1. Adjusting the leveling screw on the leveling pad will raise
or lower the tripod leg. Adjust one or more of the leveling
screws until the bubble is centered in the circle of the
bubble level. The small holes on the side of the leveling
screw and locking ring can accept a small “tool,” such as
a Phillips screwdriver shaft or an Allen wrench, to aid in
turning them, if needed (Figure 7).
We found it helpful to lift the corresponding tripod leg with
one hand (yes, it’s heavy!) while turning the leveling screw
with the other hand.
2. Lightly tighten the lock rings on all three pads after the
mount is leveled.
Figure 8. The hand controller bracket installed.
Figure 10. When installing the mount on the tripod pier,
align the metal post on the pier with the slot on the mount’s
baseplate.
Figure 9. If the azimuth adjustment bolts are already
installed, make sure there is a wide gap between them in the
slot.
Gap
Altazimuth
adjustment
knob
Altazimuth
adjustment
knob
Metal
post
Slot
Slot for
metal
post

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2.4 Attaching the Counterweight Shaft and
Counterweights
CAUTION: Always install the counterweight(s) before
installing your telescope on the mount! (And when pack-
ing up, always remove the telescope from the mount
before removing the counterweights.)
1. Thread the counterweight shaft into the mount
(Figure 13a).
2. Remove the safety stop knob from the end of the
counterweight shaft.
3. Loosen the lock knob on the counterweight(s), then
slide one or more counterweights (depending on your
instrument payload) onto the shaft. Tighten the lock knob.
4. Replace the safety stop knob on the counterweight shaft
(Figure 13b).
Figure 13. (a) The counterweight shaft threads into the
mount. (b) Install the counterweight(s) and replace the safety
stop knob.
Figure 12. Install the azimuth adjustment knobs and thread
them in all the way.
Figure 11. Install the two azimuth locking bolts.
Primary
locking
knob
Satefy
stop knob
Jackscrew
handle
Altitude
jackscrew
Altitude
lock bolt
Azimuth
locking bolt
Bubble
level
Small
washer
Slot
Large
washer
Azimuth
adjustment
knobs
Altitude
lock knob a.
b.

8
2.5 Setting the Latitude
1. Make sure the two large altitude lock knobs and the two
altitude lock bolts are all loosened slightly.
2. Use the jackscrew handle to set the mount angle to your
latitude, referring to the latitude scale and pointer on the
left side of the mount (Figure 14). (If you don’t know your
latitude, consult a geographical atlas or look it up on the
internet.) For example, if your latitude is 36° North, set
the pointer to 36.
3. Tighten the two large altitude lock knobs and the two
altitude lock bolts. Note that when you perform a polar
alignment, you will need to loosen these knobs and
bolts a very slight amount to permit adjustment. Then
you should lightly tighten them once polar alignment has
been established.
2.6 Adjusting the Azimuth
1. Make sure the azimuth locking bolts are slightly
loosened.
2. Use the azimuth adjustment knobs to move the mount in
either direction. To do this, loosen one knob by turning it
counterclockwise, then turn the opposite knob clockwise.
3. When you’ve rotated the mount to the desired position,
carefully tighten the two azimuth adjustment knobs. Then
lightly tighten the two azimuth locking bolts.
Note that when you perform a polar alignment, you will need to
loosen the azimuth locking bolts a very slight amount to permit
adjustment. Then you should lightly tighten them once polar
alignment has been established.
3. Installing a Telescope on
the Mount
The HDX110 EQ-G mount is designed to hold a maximum
instrument payload of up to 110 lbs. This will vary with the
length of the telescope: for longer telescopes, which have a
longer moment arm, the maximum weight will be less.
3.1 Installing the Telescope
1. Before installing a telescope, be sure that:
• The counterweight shaft is pointing toward the ground.
• The counterweights are installed on the counterweight
shaft and have been moved to the bottom end of the
shaft.
• The R.A. axis is secured by tightening the R.A. clutch
lever.
2. Release the Dec. clutch lever and rotate the saddle
until the arrow on it points either forward or to the right,
depending on your preference. It’s shown pointing
forward in Figure 15. Then retighten the Dec. clutch lever.
3. Loosen the three saddle clamp knobs alternately until the
width of the groove is slightly wider than the width of the
dovetail bar on your telescope or telescope tube rings.
4. While holding the telescope securely, seat or slide the
dovetail bar of the telescope into the dovetail groove of
the saddle. Then, while still supporting the telescope with
one arm, tighten the three saddle lock knobs alternately
to secure the dovetail bar in the saddle.
3.2 Balancing the Telescope
To minimize stress on the motor drive system and ensure
smooth, accurate movement of a telescope on both axes of
the mount, it is imperative that the optical tube be properly bal-
anced. Proper balancing is critical for accurate tracking. We
will first balance the telescope with respect to the right ascen-
sion (R.A.) axis, then the declination (Dec.) axis.
Figure 14. Refer to the latitude scale to set the mount to
the latitude of your observing or imaging site.
Figure 15. When installing the telescope, the arrow on the
saddle should be pointing forward or to the right.
Latitude
scale
R.A. clutch lever
Pointer
Dec. motor housing
R.A. motor
housing
Saddle
clamp
knobs
Dec.
clutch
lever
Arrow

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1. Keeping one hand on the telescope optical tube, loosen
the R.A. clutch lever (Figure 15). Make sure the Dec.
clutch lever is tightened, 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(s) along the shaft until it exactly counterbalances
the telescope. That’s the point at which the shaft remains
horizontal even when you let go of it. Once balance is
achieved, retighten the counterweight lock knob.
3. To balance the telescope on the Dec. axis, first tighten
the R.A. clutch lever, with the counterweight shaft still
in the horizontal position. Then with one hand on the
telescope optical tube, release the Dec. clutch lever
and check for any rotation. If there is some, you’ll need
to adjust the telescope forward or back in the saddle
or in its tube rings until it remains horizontal when you
carefully let go of it. (You will likely have to swing the R.A.
axis so the telescope is back on top of the mount before
making this adjustment.)
The telescope is now balanced on both axes. When you loos-
en the clutch 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.
NOTE: For imaging, it is recommended that the mount
be slightly IMBALANCED – weighting the R.A. axis to the
EAST and the Dec. axis in either direction. The imbalance
should be very slight and should be implemented after
you have found the correct balance point using the above
procedure. This weight offset keeps a minimal load on the
gears at all times, which improves guiding behavior.
So for the R.A. axis, if the telescope is on the west side of the
mount, slide the counterweight down the counterweight shaft
(which is on the east side of the mount) a bit – 3 centimeters
or so should be enough. If the telescope is on the east side of
the mount, slide the counterweight up the shaft by the same
distance.
4. Polar Alignment
The HDX110 EQ-G mount can be polar aligned either with aid
of the optional, externally mounted polar-axis scope (avail-
able from Orion) or by the iterative polar alignment routine in
the SynScan hand controller. The iterative method does not
require the polar scope, and it can be done even without direct
visual access to Polaris (in Northern hemisphere) or Octans
(in Southern hemisphere). The iterative method is the more
accurate of the two methods.
4.1 Preparing the Mount for Polar Alignment
1. Set up the mount as directed in Part 2. We recommend
performing the polar alignment with the telescope and
other equipment installed.
2. Referring to Figure 12, slightly loosen the primary
locking knob and the two azimuth locking bolts, then
use the azimuth adjustment knobs to rotate the mount
until the azimuth locking screws are centered in the slots
(Figure 11). Lightly tighten the azimuth locking screws.
3. Loosen the altitude lock knobs and altitude lock bolts,
then lightly tighten them.
4. Tighten the primary locking knob and then loosen it 1/4
turn.
5. Move the tripod to roughly align the R.A. axis to true
north (or south for use in Southern hemisphere).
6. Install the handle on the altitude jackscrew and use it to
set the latitude scale to your local latitude (Figure 14).
4.2 Polar Alignment Using the SynScan Hand
Controller
1. Select 2-Star or 3-Star alignment to align the mount for
GoTo operation, then perform the polar-alignment routine
detailed in the SynScan Hand Controller manual. Repeat
these operations several times until the SynScan hand
controller reports a small polar alignment error after the
2-Star alignment or 3-Star alignment.
2. At the end of the polar-alignment routine, tighten the
primary locking knob, and then tighten the azimuth
locking screws, the altitude lock knobs, and the altitude
lock bolts. You should observe the final alignment star in
the eyepiece while alternately tightening these symmetric
knobs and screws, to try to minimize the movement of
the alignment star in the eyepiece while locking things
down.
3. It is recommended to remove the jackscrew handle after
the polar-alignment is completed, to avoid inadvertently
hitting it or having a cable catch on it, either of which
could disturb the polar-alignment.
4.3 Polar Alignment Using the Optional Polar-Axis
Scope
Instructions for using the polar-axis scope are included with
that accessory and are available for viewing or download on
our website. Figure 16 shows the polar-axis scope installed
on the mount.
Figure 16. Optional polar-axis scope installed on the
HDX110.

10
5. Drive Panel Interface
5.1 Drive Panel
The drive panel of the HDX110 EQ-G is shown at right (Figure
17).
5.2 Panel Interface Components
POWER: This is a threaded 12V DC power input jack that pro-
vides a secure connection to the power source. Align the index
on both the connector of the cable and the input jack on the
drive panel, then insert the connector into the jack and thread
it on (Figure 18). The “cigarette lighter” plug on the other end
of the cable connects to your 12V DC field battery or AC-to-DC
adapter.
AUTO GUIDE: A 6-pin RJ-12 jack is for connecting an autogu-
ider. It is compatible with any autoguider with an ST-4 type
interface.
HAND CONTROLLER: This RJ-45 8-pin jack is for connecting
the coil cable of the SynScan hand controller.
SNAP: This stereo jack allows connection to a camera’s shut-
ter control port. The SynScan hand controller can control a
camera to take pictures automatically via this interface. The
camera control cable included with the HDX110 mount is com-
patible with select Canon EOS series DSLR cameras. It has
a right angle 2.5mm stereo plug on one end for connection to
the drive panel and a straight 2.5mm plug on the other end for
connection to the camera. Cables for other cameras can be
sourced optionally or custom made.
ON/OFF Switch: Turns on and off the power to the mount and
hand controller. The power LED serves as a power-on indica-
tor and provides other status information:
1. Steady on: Power voltage is normal.
2. Slow flashing: Power voltage is low; continuing to operate
the mount may damage the battery (if a 12V lead-acid
battery is in use).
3. Fast flashing: Power voltage is extremely low; continuing
to operate the mount may damage the battery and the
motor controller in the mount.
4. Intermittent single flash: The PPEC training routine has
been triggered, but the controller board in the mount has
not received the worm index signal and the PE correction
recording has not started yet.
5. Intermittent double flash: The PPEC training routine has
been started and the controller board in the mount has
received the worm index signal and started to record the
PE correction. When the intermittent double flash stops,
it means the PPEC training has finished.
6. Intermittent triple flash: Sidereal tracking with PEC is now
enabled.
5.3 Pinout of the Interfaces (Figure 19)
Note:
• The SNAP port provides two trigger signals to the stereo
plug. The signal to the head of the plug is issued slightly
later than the signal to the ring of the plug.
• For a camera that needs only a shutter-release signal,
either trigger signal will work. For a camera that requires
a “Focus” signal ahead of the shutter-release signal, both
signals will be utilized.
5.4 Connecting the SynScan GoTo Hand
Controller
The coil cable for the SynScan hand controller has RJ-45
connectors on each end. Plug one connector into the Hand
Control port of the drive panel and the other connector into the
RJ-45 port on the bottom of the SynScan controller. Push the
connector into the port until it clicks into place.
The smaller modular port next to the RJ-45 port on the hand
controller enables serial communication between the HDX110
mount and a computer running astronomy software such as
Starry Night Pro. For that you will need the RS-232 computer
interface cable that was included with the mount. If your com-
puter does not have an RS-232 port, you will also need a
Figure 17. The drive panel of the HDX110.
Figure 18. The right angle connector of the included 12V
DC power cable threads onto the power connector on the
mount.
On/Off
switch
Power
cable
connector
Autoguide
port
Hand
controller
port
SNAP
port

11
USB-to-serial adapter. Check telescope.com for an available
adapter.
The 12V DC power jack on the hand controller is used only
for updating the firmware in the hand controller or for brows-
ing the object database without connecting to the telescope
mount. Do not connect the hand controller to a power source
when using the mount for normal operation!
5.5 Power Supply Requirements
The HDX110 EQ-G requires power from a 12V DC marine
battery or an AC-to-DC power supply with a 3-amp or higher
output current rating.
• Output Voltage: DC 11V (minimum) to DC 16V (maximum).
Voltage not in this range could cause permanent damage
to the motor controller board or the hand controller.
• Output Current: 4A for power supply with 11V output
voltage, 2.5A for power supply with 16V output voltage.
• Do not use an unregulated AC-to-DC adapter. When
choosing an AC adapter, it is recommended to use a
switching power supply with 15V output voltage and at least
3A output current.
• If the power voltage is too low, the motor controller will stop
the motors automatically.
6. Other HDX110 EQ-G
Features
6.1 Auto-Home Function
The HDX110 EQ-G mount has two integrated home position
sensors. With the SynScan hand controller the mount can be
placed to the same home position after turning on the power.
For detailed information, refer to the SynScan Hand Controller
instruction manual.
6.2 Auxiliary Encoder Function
Auxiliary encoders on both the R.A. and Dec. axes of the
HDX110 EQ-G mount enable it to continue tracking even
when the user unlocks the clutches and manually rotates the
mount in R.A. and Dec. With this feature, you can manually
operate the mount any time without worrying about losing the
mount’s GoTo star alignment status. When you want to oper-
ate the mount with the SynScan hand controller again, no re-
alignment is required; all that is needed is to re-lock the clutch
levers. This feature can be enabled or disabled in the SynScan
Hand Controller.
6.3 Permanent Periodic Error Correction
The HDX110 EQ-G mount is equipped with an index on its
R.A. worm, thus the motor controller can keep tracking the cur-
rent position of the worm. After a proper PEC training routine,
in which the training data is stored in the motor controller per-
manently, a user can start the periodic error correction (PEC)
at any time to improve the tracking performance for astropho-
tography. A training process is not required in the next observ-
ing session (assuming that the polar alignment is always accu-
rate), thus this is a Permanent Period Error Correction (PPEC).
A user can train the mount by guiding either manually or elec-
tronically with auto-guiding. For detailed instructions, please
refer to the relevant section in the SynScan Hand Controller
instruction manual.
6.4 Batch Exposure Function
The HDX110 EQ-G mount has a SNAP port that can control
the shutter of a DSLR camera (see Figure 17). Working with
the SynScan hand controller’s “Camera Control” function, you
can set the number of exposures, exposure duration, and
exposure interval for up to eight different sets of exposures.
For detailed information, refer to the SynScan Hand Controller
instruction manual.
Figure 19. Schematic diagrams of the drive panel’s electronic interfaces.
2
3
4
1
5
6
7
8
HAND CONTROL
GND
Vpp+
RX(3.3V)
TX(3.3V)
2
3
4
1
5
6
AUTO GUIDE
GND
+5V
RA+
RA-
DEC+
DEC-
R
560
C
10uF/25V
SNAP
Optoisolator
GND
GND
Vpp+
POWER
Control Signal
Internal Circuit
GND
TRIGGER
DELAYED
TRIGGER

12
7. Care of Your HDX110
EQ-G Mount
To protect the equatorial mount, we recommend transporting
and storing it in its original shipping box or in an optional hard
case.
CAUTION: Never set the equatorial head down such
that the motor covers or encoder/gear housings bear
the weight of the mount, as this could damage those
components and the hardware inside them. If you need
to set the mount down on the ground or other flat sur-
face, always orient the mount in the “upright” position in
which only the bottom plate contacts the surface.
Addendum: Adusting the
Declination Axis Backlash
If you believe that the declination axis (DEC) of your HDX110
EQ-G mount has unwanted backlash, or on the contrary that
the DEC worm and ring gear are binding due to being too tight-
ly meshed, follow this procedure for adjusting the gear mesh.
You will need a Philips screwdriver and a set of metric Allen
keys to perform this adjustment.
1. Rotate the saddle of the mount head to its default
position and then lock the DEC clutch lock lever as
shown in Figure 20. Rotate the saddle back and forth
to feel how much “play” there is (Figure 21, see Note
below). This is an indication of how tightly the worm is
meshed to the ring gear. It is normal to feel a tiny bit
of play. If you don’t feel any movement, not even the
slightest jog, the DEC gear mesh may be too tight. If you
feel a lot of play, the gears may be too loosely meshed.
NOTE: It may help to install a long dovetail plate in the
saddle, as shown in Figure 21, to give you a longer
moment arm for rotating the saddle back and forth. In our
tests it was easier to feel the amount of backlash when
we rotated the DEC axis via an installed dovetail plate.
2. Now connect the hand controller to the mount and turn
on the power. Use the hand controller to slew the saddle
several degrees left (Figure 22). Rotate the saddle back
and forth by hand again to feel the amount of play, as you
did in Step 1. Can you feel even the slightest jog?
3. Slew a few more degrees in the same direction as in
Step 2, and again rotate the saddle back and forth to feel
the amount of DEC play.
4. Repeat the previous step, going a few degrees at a time,
until the DEC axis has completed a 360° rotation, to find
the position of the saddle where you feel the smallest
amount of play. That’s where the gap between the worm
and ring gear is smallest. Slew several degrees left and
right of this position to pinpoint the exact position where
the smallest gap of gear mesh is found. In the following
steps, you will carefully adjust the gear mesh to the
proper setting.
Figure 20: Start with the dovetail saddle in the “default”
position, pointing straight ahead.
Figure 21: It’s best to install a wide dovetail plate in the
saddle to test1 for DEC backlash, as it provides a longer
lever arm. With the DEC clutch lock lever tightened, grasp the
plate firmly with both hands – one hand on each end – and
jog it rotationally back and forth and feel for “play” (backlash).
Figure 22: Slew the saddle using the hand controller a few
degrees, then jog it again as in step 2 and note the amount
of backlash. Repeat this step several times until the saddle
has rotated 360 degrees.
Wide dovetail plate
(sold separately)
Saddle
Dec clutch
lock lever

13
NOTE: When locating the position of the least amount
of play, or tightest gear mesh, the smaller the angle the
saddle is rotated, the more precise the position can be
pinpointed.
5. Remove the plastic DEC motor housing by unscrewing
the three screws shown in Figure 23, using a Philips
screwdriver and a 2mm Allen key.
6. Now with a 3mm Allen key loosen by a quarter turn only
the two screws that connect the DEC motor to the seat
plate as shown in Figure 24. These two screws are
located diagonally across the motor; only one is visible
in the figure. (For a very small DEC adjustment, you can
skip this step.)
7. With a 4mm Allen key, unscrew the four screws at the
bottom of the worm gear housing a quarter or half turn
only, as shown in Figure 25. Do not over-loosen these
screws!
8. Now with the same Allen key completely remove the
three cover screws on the front of the DEC housing
(Figure 26). These screws are cosmetic only. Once they
are removed you will be able to get to the Allen screws
inside the housing, which are the ones used to actually
adjust the gear mesh.
9. Adjust the three screws as shown in Figure 27 to change
the gear mesh of the DEC worm and ring gear:
To TIGHTEN the mesh (REDUCE the backlash), first
loosen the center screw just a little bit by turning it
counterclockwise. Then tighten the outer two screws
evenly by turning them clockwise.
Figure 27: The three backlash adjustment screws are set
deep inside the housing. The outer two are adjusted with
a 4mm Allen key while the center screw requires a 2.5mm
key. Be sure to follow the proper procedure in the text! Do
not over-tighten any of the screws or you could damage
the gears!
Figure 23: Removing the Dec motor housing is done by
unthreading two Philips screws (a) and one Allen screw (b). Figure 26: Completely remove the three cosmetic cover
screws on the front plate and set them aside.
Figure 24: Loosen by a quarter turn the two diagonally
opposed screws that fasten the motor to the seat plate.
Figure 25: Loosen the four Allen screws underneath the
DEC worm gear housing by no more than ½ turn, to allow
the worm block to move during the adjustment process.
Philips
screws
a. b.
Allen
screw

14
To LOOSEN the mesh (INCREASE the backlash), first
loosen the outer two screws a little bit by turning them
counterclockwise the same amount, then tighten the
center screw by turning it clockwise.
Loosen/Tighten the three screws only in small incre-
ments to avoid over-adjustment or possible damage
to the worm or ring gear!
10. Now, with the DEC clutch lock lever tightened, jog the
saddle rotationally back and forth again by hand and see
if the backlash has decreased to a more desirable level.
11. After the gear mesh has been adjusted to your
satisfaction, re-install the three cover screws removed in
Step 8, and then re-tighten the four screws on the bottom
of the worm gear housing loosened in Step 7.
12. Before retightening the two screws loosened in Step 6,
use the hand controller’s up or down directional button
to drive the DEC motor and the worm gear for a few
seconds. This will allow the motor to auto-center and
align the drive shaft with the worm rod. After this is done,
the two screws can be fully tightened.
13. Now use the hand controller to slew the DEC axis
at least 2 complete cycles (720 degrees) to check if
there is any stalling or binding as a result of your mesh
adjustment. If there is, be sure to repeat this procedure
from the top and make the necessary adjustments. If
there isn’t, re-attach the DEC motor housing with the
three screws removed in Step 5.
Specifications
Product name HDX110 EQ-G
Mount type German equatorial GoTo
Payload (counterwts. excl.) 110 lbs. (50kg), depending on
telescope length
Saddle type Wide (Losmandy style)
R.A. worm wheel Dia. 219.5mm, 435 teeth,
aluminum
Dec. worm wheel Dia. 219.5mm, 435 teeth,
aluminum
RA shaft Dia. 55mm, aluminum
Dec. shaft Dia. 55mm, aluminum
Motors 0.9° hybrid stepper motors
Transmission 435:1 worm drive + 64
microstep/0.9° stepper motor
drive
Resolution 11136000 counts/rev; approx
0.12 arc-second
Tracking accuracy typically ±3 arc-seconds (native)
Maximum slewing speed 3.3° /s
Tracking rates Sidereal, solar, lunar
Autoguiding speeds 0.125x, 0.25x, 0.5x, 0.75x, 1x
PEC 100 segments permanent PEC
Latitude adjustment range 10° – 65°
Azimuth adjustment range ±10°
Counterweight shaft Dia. 31.5mm, length 15.9"
(403mm), weight 5.7 lbs. (2.6kg)
Counterweight 22 lbs. (10kg) each (x2)
Tripod pier Height range 31.1"-43.3" (790-
1100mm)
Tripod leg diameter 2.4" (60.5mm)
Tripod min. folded length 32.5" (82.6cm)
Tripod leveler pads Qty 3, all metal, height range
2.7"-3.7" (69-94mm)
Polar alignment Software assisted (iterative) or
optional polar scope
Polar axis scope Optional, external mounting
Hand controller SynScan, illuminated keypad
Database 42,000+ objects
Celestial object catalogs Messier, NGC, IC, SAO,
Caldwell, Double Star, Variable
star, Named stars, Planets
Pointing accuracy Up to 5 arc-min (RMS)
GoTo alignment 1-star, 2-star, 3-star
Resolution of aux. encoders 17,624 Counts/rev., approx. 1.2
arc-minutes
Weight of EQ head
(excl. Counterweight shaft) 55 lbs. (25kg)
Weight of Tripod Pier 63 lbs. (28.6kg)
Case for EQ head Dimensions: 19.5"x23.5"x25.5",
incl. casters
Power requirement 11-16V DC, 4A
Power cable 12V DC cigarette lighter style
with threaded connector to
mount
RS-232 cable Included

15
Saddle Head
TripodMountMount
Mount Bottom Plate
M12
160
54
Ø124
100
76
76
4-M 6
2-Ø6
800~1100
894
Ø140
Ø180
45°
473
360
272

16
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. Proof of purchase (such as
a copy of the original receipt) is required. This warranty is only valid in the country of purchase.
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. It is not
intended to remove or restrict your other legal rights under applicable local consumer law; your state or
national statutory consumer rights governing the sale of consumer goods remain fully applicable.
For further warranty information, please visit www.OrionTelescopes.com/warranty.
Orion Telescopes & Binoculars
Corporate Offices: 89 Hangar Way, Watsonville CA 95076 - USA
Customer Support: www.OrionTelescopes.com/contactus
Copyright © 2014 Orion Telescopes & Binoculars
All Rights Reserved. No part of this product instruction or any of its contents may be reproduced, copied, modified or adapted, without the prior
written consent of Orion Telescopes & Binoculars.