ASTRO-PHYSICS 1100GTO User manual

1100GTO1100GTO German Equatorial Mount withGerman Equatorial Mount with
GTOCP4 Servo Motor DriveGTOCP4 Servo Motor Drive
Mounts ShippedMounts Shipped
Starting inStarting in
March 2021March 2021
Keypad Optional
Astro-Physics, Inc.Astro-Physics, Inc.
11250 Forest Hills Road11250 Forest Hills Road
Machesney Park, IL 61115Machesney Park, IL 61115
Telephone: [phone]Telephone: [phone]
Fax: [phone]Fax: [phone]
[email protected][email protected]
www.astro-physics.comwww.astro-physics.com

1
ASTRO-PHYSICS

MOUNTS  GTOCP4 SERVO MOTOR DRIVE
ABOUT THIS MANUAL 3
1100GTO PARTS LIST 4
1100GTO-AE PARTS LIST 4
1100GTO-AEL PARTS LIST 4
RECOMMENDED AND OPTIONAL ACCESSORIES 5
MECHANICAL SPECIFICATIONS 6
INTRODUCTION 7
Why Polar Alignment is Important 7
ASSEMBLY DIAGRAMS 8
1100GTO Assembly Diagram 8
1100GTO-AE or -AEL ASSEMBLY Diagram 9
Handy Tools to Have on Hand 10
WHAT IS MEANT BY “INITIALIZATION”? 10
QUICK START SUMMARY – NEW INSTALLATIONS using Keypads 11
QUICK START SUMMARY – NEW INSTALLATIONS using Computers 12
AT YOUR OBSERVING SITE 13
Assemble Pier (purchased separately) 13
Attach Polar Axis Assembly to Pier 13
Latitude Adjustment for 1100GTO German Equatorial Mounts 14
Special 90 Degree Alt-Azimuth Position 15
ASSEMBLY INSTRUCTIONS 16
Understanding Cabling Di󰀨erences in Non-AE and AE Mounts 16
1100GTO 16
1100GTO-AE / AEL 16
ASSEMBLY OF R.A. AND DEC. AXES 17
Assembly Procedure 17
Disassembly procedure 18
CABLE MANAGEMENT 19
Preparation 19
The Basics 19
The Specics 19
Routing Cables if You Plan to Use the Cable Router When Using the Polar Scope 20
Routing Cables if You Don’t Plan to Use the Cable Router 21
ATTACH MOUNTING PLATE 22
Fixed Mounting Plate Options 22
Losmandy D-Style Compatible Saddle Plates 23
Side-by-Side and Vixen Style Plate Options 24
ATTACH COUNTERWEIGHT SHAFT AND COUNTERWEIGHTS 25

2
ATTACH MOUNTING RINGS AND SCOPE 25
UNDERSTANDING THE R.A. AND DEC. CLUTCH KNOBS 26
BALANCING THE TELESCOPE 27
Preliminary Balancing 27
Precision Balancing 27
Disengaging the Worm and Worm Wheel 27
ALTITUDE AND AZIMUTH ADJUSTMENTS – ROUGH POLAR ALIGNMENT 29
POLAR ALIGNMENT OPTIONS – FINE POLAR ALIGNMENT 30
Methods for ne polar alignment 30
Making Precise Altitude and Azimuth Adjustments 31
Fine Altitude Adjustment 31
Tips for Adjusting the Altitude 31
Fine Azimuth Adjustment 32
Precision-Adjust Rotating Pier Base with Azimuth Bearing 32
Using Software to Improve Pointing Accuracy 32
MISCELLANEOUS ITEMS 33
Lanyard Post and Bubble Level 33
Warning for Dec. Servo Cable 33
SLEWING YOUR MOUNT IN BELOW FREEZING TEMPERATURES 33
AUTO-ADJUSTING GEARBOX - NO MORE WORM MESHING! 34
Checking and Adjusting the Gearbox Backstops in R.A. and Dec. 34
What to do if you believe that there is a backlash in the gearbox 35
SOME IMPORTANT NOTES 36
MOUNT CARE, CLEANING AND MAINTENANCE 37
Care 37
Cleaning and Touch-up 37
Counterweight Appearance 37
Routine Mount Maintenance 37
Worm Wheel Maintenance 37
TROUBLESHOOTING, TIPS AND SUPPORT 38
Troubleshooting and Tips 38
Additional Support 41
APPENDIX A: DECLINATION AXIS BACKLASH TESTS 42
PulseGuide™ 42
Dec Backlash Test 1 42
Dec Backlash Test 2 42
After Running Tests 1 and 2 43
Dec Backlash Test 3 43
MaxImDL™ 43
Step 1 43
Step 2 43
Step 3 43
APPENDIX B: MOUNTING PLATE FASTENER CHART 44

3

This version of the 1100GTO, 1100GTO-AE and 1100GTO-AEL Manual was prepared for the production run of mounts that
began shipping in November of 2018. There are a few feature di󰀨erences between the encoder and non-encoder versions
of the mounts that warrant special attention and connection procedures. Whereas some division of context is provided
within this manual, these di󰀨erences will primarily be addressed in the separate AP AE Utility CD that is provided with the
1100GTO-AE and 1100GTO-AEL mounts.
You should also note that this manual is actually one component of a three document system. If you choose to purchase
the optional Keypad, then you’ll receive its manual. The Keypad Manual applies to all mounts, detailing the keypad’s many
features and extensively explains its operation. The third manual is the GTO Servo Motor Drive System. Like the Keypad
Manual, the GTO Manual is universal to all mounts that use the Astro-Physics GTO Servo Motor Drive System with the
GTOCP4 Servo Control Box. This 1100GTO, 1100GTO-AE and 1100GTO-AEL manual, on the other hand, will cover the
1100GTO’s mechanical features and physical operations.
As always, we highly recommend the Technical Support Section of our Web site for the latest information and for future
updated versions of this manual.
A nal note and an apology to our friends in the southern hemisphere. Many of the instructions in this manual are written
entirely from the point of view of those of us in the northern hemisphere. Since descriptive terms like left and right are
meaningless without a dened point of reference, we tend to use east and west to avoid ambiguity. The east and west
sides of a German equatorial mount are, of course, reversed in the southern hemisphere. At one point, our thought was to
always use phrases like the following: “... on the east side (west side in the southern hemisphere) ...” This quickly became
cumbersome and made the text more di󰀩cult to read. For simplicity, we decided to leave many of the explanations in their
northern hemisphere framework. To our southern hemisphere friends: We appreciate you no less and apologize for this
unintended slight. We know, however, that you are all smart enough to make the necessary translation to “down under”
appropriate instructions. Thank you for your understanding.
󰀨

Mount Serial Number: _____________________________________________
GTOCP4 Serial Number: _____________________________________________
Keypad Serial Number: _____________________________________________
Purchase Date: _____________________________________________

4
1100GTO
1 Polar Fork / Right Ascension Axis (R.A.) Assembly
1 Declination Axis (Dec.) Assembly
1 GTO Servo Control Box (GTOCP4)
1 GTOCP4 Control Box Adapter (M11010) and (2) 8-35 x 3/8” Thumbscrews
1 16.675” x 1.875” Stainless Counterweight Shaft (M9404-B) with machined Safety Stop (M12676)
1 R.A. Cable Router Insert (M11039)
1 R.A. / Dec. Y-Cable (S1100GYCR)
1 D.C. power cord set - 6’ cable with power pole connectors (CABPP6), 18” cable with cigarette plug (CABPP18C) and
18” cable with ring connectors (CABPP18R) and clip (FPCLIP)
1 15’ Straight-through Serial Cable (CABSER15)
1 Hex key Set
2 SS Lanyard Posts (cannot ship on mount due to packing)
10 3/4” x 8” Velcro Cable tie wraps
1 USB Flash Drive containing: APCC Standard, PEMPro™ v3 Software and PDF of Instruction manuals
Instruction Manuals and Registration Card
Fasteners:
(4) 1/4-20 x 5/8” SHCS (for safety backup of dovetails)
(7) 5/16-18 x 5/8” SBHCS (pier adapter) (6 + 1 extra)
(7) 5/16” at washers (pier adapter)
(2) 8-32 x 1/2” SBHC (control box adapter lockdown)
(2) 0.187” Shoulder bolt (option for control box adapter attachment)
1100GTO-AE
All items listed above for the 1100GTO (except Y-cable), plus:
1 R.A. and Dec. Absolute Encoders, installed
1 R.A. and Dec. Readheads with wire harnesses, standard temperature version, installed
1 Junction Box and X-cables (attached to mount)
1 USB Flash Drive with APCC Pro
1 Screwdriver, 1/8” at

All items listed above for the 1100GTO-AE, except that the Readheads are the Extended Temperature Version.

5




● Astro-Physics has several heights and styles to choose from.
Options: 8” Advanced Telescope Systems (ATS) portable pier with 119FSA-FP adapter or Losmandy Folding Heavy-
Duty Tripod (LMFHDT-AP)
● 5 lb. (5SCWT), 10 lb. (10SCWT), 18 lb. (18SCWT) and 30 lb. (30SCWT188) are available.
● We o󰀨er two choices: 13.8-volt, 5-amp supply (PS138V5A) or
Variable-volt, 25-amp supply (PSVPW25A). Both supplies are ltered and regulated. We recommend the Variable-volt
supply for heavier loads and colder weather. The mount should have its own power supply.
● Several sizes and types are available from a variety of vendors.
Be sure that your battery pack can supply adequate power for an entire observing session! Please refer to power
requirements under Features and Specications on next page. We recommend having separate batteries – one for
the mount and one or more for all other accessories: camera, computer, dew removers etc. You may wish to consider:
○For connecting the CP4 Power Cable to battery terminals.
○To monitor your power consumption.

● with 15’ coiled cable. Hand-held computer to operate the mount without a PC and
additional software.
● For heavier loads.
● Various guiding congurations can take advantage of the 1100GTO’s autoguider port.
The autoguider port receptacle (RJ-11-6) uses the industry standard SBIG ST-4 wiring setup.
● Accessory Tray (TRAY08) and/or Eyepiece Accessory Trays (TRAY08H)
with Bi-Level (TRAYSB) or Single Level (TRAYSB1) Support Bars. Keep things close at hand.
● For attaching the 1100GTO to your own custom pier or tripod.
●For attaching the 1100GTO to the Advanced
Telescope System (ATS) pier, or to your own custom pier or tripod when a at pier plate is needed.
● AP Right-Angle Polar Alignment Scope (RAPAS) and Losmandy Polar Alignment Scope
(PASILL4-179) – Many users nd a polar alignment scope useful for zeroing in on the pole quickly. This is particularly
important when using portable setups.

6

Construction All CNC machined aluminum bar stock, stainless steel, brass; stainless steel fasteners
Finishing and Assembly Every part is hand-nished and inspected. All assembly is done by hand, by highly skilled
mount assembly sta󰀨.
Worm wheel - R.A. & DEC. 7.2” (183 mm), 225 tooth aluminum
Worm gear - R.A. & Dec. 0.71” (18 mm) diameter, special low-wear alloy
Axis shaft - R.A. & Dec. 3.15” (80 mm) diameter
Shaft axis bearings - R.A.
& Dec. 3.94” (100 mm) diameter
Latitude range 0 to 78 degrees and 90 degrees for Alt-Az
Azimuth adjustment Approximately 18 degrees (+/- 9 degrees from center)
Counterweight shaft 1.875” (47.6 mm) diameter x 16.675” (424 mm) usable length, includes large machined
safety stop knob; weight: 12.9 lb. (5.8 kg). Optional shaft extension available.
Weight of mount
R.A. axis / polar fork: 27.6 lb. (12.5 kg)
Dec. axis: 15.6 lb. (7.1 kg)
Dec. top plate 1.5 lb. (0.7 kg)
Capacity of mount
Approximately 110 lb. (50 kg) scope and accessories (not including counterweights),
depending on length. Recommended for refractors up to 200 mm, 14-16” Cassegrains,
Ritchey-Chrétiens and CDKs.
These are only guidelines. Some telescopes are very long for their weight or heavy for
their size and will require a larger mount. Remember also that imaging requirements are
more rigid than visual observation.
Instrument mounting
interface Reference the “Attach Mounting Plate” section of the manual.
Pier adapter base 7.730” (196.3 mm) diameter. The base is an integral part of the mount and azimuth
adjuster.
For a complete listing of the servo control, power, and periodic error specications, please see the
GTO Servo Drive System Manual.

7
INTRODUCTION
The 1100 German equatorial was designed to meet the needs of the advanced observer who requires a mount with
maximum strength and rigidity and minimum weight. The excess material in both axes has been carved out while retaining
a heavily ribbed structure for internal strength and rigidity. A unique dovetail was machined into the mating surfaces of
the R.A. and Dec. axes and also between the Dec. axis and the Dec. axis Top Plate. This feature allows quick and easy
assembly in the eld without any tools.
The DC servo motor drive with GTO computer system, the optional keypad with its digital display screen, and the included
AP V2 ASCOM Driver and PEMPro™ v.3.x software all combine to o󰀨er extraordinary sophistication for today’s observer.
Whether you enjoy visual astronomy exclusively or plan an aggressive astrophotography or CCD imaging program, this
mount will allow you to maximize your night out under the stars.
The advanced keypad features allow you to slew automatically to objects in a wide range of databases as well as any R.A./
Dec. or Alt./Az. coordinate. A large selection of common names for stars and other objects makes your selection a snap.
The rapid slew rate of 5 degrees per second (1200x) allows you to locate objects very quickly and accurately. You will be
very pleased with the intuitive operation of this keypad. There are no complicated sequences of keystrokes to remember.
It is so easy to use that even if you don’t use it for a few months, you will feel at home with the keypad very quickly.
The keypad is only one way of controlling the versatile Astro-Physics GTO Servo System. From its very conception, the
servo controller was designed to work with any software that was written to use our published command set. We do not
lock you into any proprietary software or mandatory “additional” equipment. To increase the versatility of all our mounts,
we have developed and fully support a V2 ASCOM Driver for use with all ASCOM client software.
As mentioned above, we also include a full version of PEMPro™ (Periodic Error Management Professional) v.3.x (latest
version) for you to enhance your control and performance options. As an added bonus, all 1100GTO mounts will come
pre-loaded with the custom-tted PEMPro™ corrections from our extensive individual testing that is performed on each and
every mount. While the native peak-to-peak periodic error of your 1100GTO will be 7 arcseconds or less, you can reduce
it even further to maximize performance without auto-guiding. These software control products are detailed later in the
manual.
In addition to everything outlined above, the 1100GTO’s control and performance options will be greatly enhanced by
the Astro-Physics Command Center (APCC). APCC fully addresses all the capabilities of the 1100GTO, and adds
enhancements not currently available in the keypad or in any other software.
The 1100 is equally at home in a permanent observatory or as a portable mounting for remote star parties thanks to the
ease with which the two axes come apart. This is the perfect
mount for a mid-size refractor, Newtonian, Cassegrain or
astrograph.
In order to maximize your pleasure on your rst night out, we
recommend that you familiarize yourself with the assembly
and basic operation of the mount indoors. The temperature
will be comfortable, the mosquitoes at bay, and you’ll have
enough light to see the illustrations and read the manual.
Please take particular note of counterbalancing, use of the
clutches and operation of the keypad controller.
Why Polar Alignment is Important
Polar alignment permits accurate R.A. movement in order to
compensate for the Earth’s rotation.
If you were to take a long exposure photograph with Polaris
(often called the north star) in the center of the eld, you
would discover that all stars seem to revolve around
Polaris. This e󰀨ect is due to the rotation of the earth on
its axis. Motor-driven equatorial mounts were designed to
compensate for the earth’s rotation by moving the telescope
at the same rate and opposite to the earth’s rotation. When
the polar axis of the telescope is pointed at the celestial pole
(polar aligned) as shown in the diagram at right, the mount
will follow (track) the motions of the sun, moon, planets and
stars. As a result, the object that you are observing will
appear motionless as you observe through the eyepiece or
take astrophotos.
Equator
South North
Direction of
the Celestial
North Pole
Earth
Direction of
the Celestial
North Pole
Direction of
the Polar Axis
Horizon
Zenith
Earth’s Axis
L
a
t
i
t
u
d
e
L
a
t
i
t
u
d
e
Northern
Hemisphere
Earth’s Rotation
Mount’s
Counter-rotation

8

1100GTO Assembly Diagram
The following terms and abbreviations are used interchangeably in these instructions:
Polar axis = right ascension axis = R.A. axis = R.A. housing
Declination axis = Dec. axis = Dec. housing
Please read all instructions before attempting to set up your 1100GTO mount. The model 1100GTO is very rugged;
however, like any precision instrument, it can be damaged by improper handling. Please refer to the diagram below
for an illustration of the mount. The parts are labelled so that we can establish common terminology. Pay particular
attention to the section regarding joining and separating the R.A. and Dec. axes, as this is unique to this mount. It is
important to note the need to connect and disconnect the Dec. motor servo cable when doing so.
Control Box Adapter
located behind CP4
GTOCP4
Control Box
Removal Thumb
Screws (2)
Declination
Motor/Gearbox
Dec. Sighthole
Cover
Declination
Axis Housing
Counterweight
Shaft
Safety Stop
Altitude
Adjuster Knob
Dec. Lock
Knob (2)
Polar Fork
Assembly
Dec. Top Plate
Lock Knobs (2)
Dec. Top Plate
Cable
Channel (2)
Polar Axis
Lock Knobs (4) R.A. Axis
Housing
R.A. Sight
Hole Cover
Azimuth
Adjuster
Mounting Bolts for GTOCP4
Control Box Adapter (2)
(8-32 Shoulder Bolts or 8-32 Button Head Screws)
Polar Axis
Pivot Bolt
Cable Access
Covers (2)
Clutch Knobs
(3 each axis)
GTOCP4 Control
Box & Adapter
R.A. Motor/
Gearbox
Dec. Cable
Port Cover
Safety Screw (2)
Declination
Counterweight
Adapter
Delrin Washer
(hidden)
Absolute
Encoder
Read Head
Cover
Lanyard
Post (2)
Safety
Screw (2)

9
1100GTO-AE or -AEL ASSEMBLY Diagram
The following terms and abbreviations are used interchangeably in these instructions:
Polar axis = right ascension axis = R.A. axis = R.A. housing
Declination axis = Dec. axis = Dec. housing
Please read all instructions before attempting to set up your 1100GTO mount. The model 1100GTO is very rugged;
however, like any precision instrument, it can be damaged by improper handling. Please refer to the diagram below
for an illustration of the mount. The parts are labelled so that we can establish common terminology. Pay particular
attention to the section regarding joining and separating the R.A. and Dec. axes, as this is unique to this mount. It is
important to note the need to connect and disconnect the Dec. motor servo cable when doing so.
Declination
Motor/Gearbox
Dec. Sighthole
Cover
Declination
Axis Housing
Declination
Counterweight
Adapter
Counterweight
Shaft
Safety Stop
Altitude
Adjuster Knob
Dec. Lock
Knob (2)
Polar Fork
Assembly
Clutch Knobs
(3 each axis) Dec. Top Plate
Lock Knobs (2)
Dec. Top Plate
Cable
Channel (2)
Polar Axis
Lock Knobs (4)
R.A. Axis
Housing
Absolute
Encoder
Read Heads
Dec./R.A.
R.A. Sight
Hole Cover
Azimuth
Adjuster
Mounting Bolts for GTOCP4
Control Box Adapter (2)
(8-32 Shoulder Bolts or 8-32 Button Head Screws)
Polar Axis
Pivot Bolt
Cable Access
Covers (2)
GTOCP4
Control Box & Adapter
R.A. Motor/
Gearbox
Delrin Washer
(hidden)
Lanyard
Post (2)
Safety
Screw (2)
Dec. Cable
Port Cover
Safety Screw (2)
GTOCP4 (showing AE Cable)
1100GTO-AE & 1100GTO-AEL
Junction Box
Protective
Insert
for
Encoder
Ring
Dec. Axis with Absolute Encoder Control Box Removal
Thumb Screws (2)
Control Box Adapter
located behind CP4

10
Handy Tools to Have on Hand
In Your Accessory or Tool Box:
●Small torpedo level to level your scope when using the handy reference park positions, particularly during the daytime
polar alignment routine outlined in your Keypad manual.
● Compass - Don’t forget to know your magnetic o󰀨set when using a compass (there can be a large di󰀨erence).
On Your Smart Phone:
For the upmost of convenience, the following items can be downloaded to your smart phone, which you are likely carry with
you everywhere.
●APP(s) that allow your phone to be used as a level, inclinometer and compass. Don’t forget to know your magnetic
o󰀨set when using a compass since there can be a large di󰀨erence.
●Astro-Physics Polar Alignment app – The latitude and longitude of your current site will display. APPs are available for
iOS, Android and Windows.

In simplest terms, “initialization” is the process of giving the mount’s servo controller the information that it needs to know:
○Where is it?
○What is the time?
○How is it supposed to operate?
○ It then unparks the mount and allows you to calibrate the pointing by using a dened AP park position (if
needed).
The above is the information you entered into your software when you rst installed and set it up. For keypad users, it is
the information you entered when you followed the “First Session with your Keypad” instructions (in the Keypad manual).
These four points are detailed below.
1. Latitude and longitude coordinates tell the mount where it is. The GTOCP4 will remember where it was when last pow-
ered down, but can’t know if you have moved to a new location unless it is told.
2. Time, date and time zone give the mount the necessary time information. Time information is required to calculate the
mount’s current pointing position if it hasn’t been moved, and it is needed to calculate the meridian and the horizons.
The mount’s servo does not have an internal battery to maintain time between power-ups, so time is an essential part
of every initialization.
3. Commands to establish the tracking, guiding, centering and slew rates along with other similar parameters like PEM tell
the mount how it should operate.
4. The command to “unpark” the mount is sent. This command both ends the parked state and it also calculates the
mount’s current pointing position if the mount has not been moved manually by hand via loosening the clutches. The
decision whether or not to calibrate on a dened AP park position will depend on the circumstances.
For an established setup that has not been moved, do NOT calibrate on a park position. Resume from last parked or
last position. The unpark command will have resulted in extremely accurate calculation of the current pointing position
without further calibration being necessary.
For new setups, or if you have moved the mount with the clutches, you will need to calibrate on (aka “resume from”) an
AP dened park position.

11
QUICK START SUMMARY – NEW INSTALLATIONS using Keypads

1. Enter the Time and Location data into the Keypad. Follow the instructions in the Keypad Manual for entering your Time
and Location data into the Keypad. (Location 1 is usually your primary observing location)
2. Set the Keypad to AutoConnect: NO. This will allow you to choose the location for which you entered the data above.
Remember to power cycle the mount after the data has been entered. This will lock the information.
3. Assemble the mount. Reference your Mount Manual.
4. Balance the system. Reference your Mount Manual.
5. Polar align the mount – at least roughly. (If using the daytime routine, move this step to after the mount is initialized. If
using the RAPAS, do it before initializing.)
6. Place the system into a pre-dened AP Park position for initialization. Reference the positions shown at the end of this
Quick Start Guide.
7. Power up the mount; select your location and press GoTo.
8. The next menu has 4 choices. Choose “4=New Setup” and select the Park position that you chose in #6 above. This
will initialize the mount and ready it for going to your rst object.
9. When you arrive at your rst object you may need to use the N S E W buttons to center the object. Do so and then
press the RA DEC REV button on the bottom right, followed by the #9 button to do a ReCal of position. The following
GoTo slews to other objects should be more accurate.
10. After nishing your night’s observing (or day’s solar observing) it is best to park the mount into your chosen Park posi-
tion by pressing 2=Setup; then 4=Park / Mount Opt.; and nally choosing the Park position number where you wish to
park.
11. Power down the mount.

● “New Setup” is only used when you are setting up the mount for the rst time or if you have readjusted scope position
via the clutches and wish to restart from a “Reference Position”.
●“ResumeLastPosition” is used when you parked the mount at the end of the previous session and wish to begin a new
night of observing. Selecting it will initialize the mount and you’ll be ready to go to your rst object.
●If you are in a permanent setup, then you should set the Keypad to “AutoConnect: YES” so that when you power up
the mount, it will automatically be initialized and ready to go to your rst object. This is the most automated of the
setups using the Keypad.


1. Loosen all the R.A. and Dec. clutches so that the scope can be moved freely with your hands. Moving the scope into a
Park 3 position will provide additional safety for this procedure.
2. Command the mount to go to Park 3 using either the Keypad or a computer (whichever you have been using for the
evening). While the motors are moving, hold the scope with your hands so that it remains safe.
3. When the motors both stop, use your hands and put the scope into Park 3 (use your eyes to get close) and then tighten
all the clutches.
4. That’s it...you’re done! Orientation has been restored to the universe! When you go to your rst object you’ll need to
tweak the centering and do a ReCal, but you’ll be close.

12
QUICK START SUMMARY – NEW INSTALLATIONS using Computers

1. Install and set up your control software and drivers. For all but the AP GTO Keypad, this can be done before you even
take delivery of your mount.
a) Set up ASCOM and the drivers rst
i) ASCOM Platform 6.3 (currently) - ascom-standards.org
ii) AP V2 ASCOM driver - http://www.gralak.com/apdriver
iii) FTDI driver - http://www.ftdichip.com/Drivers/VCP.htm See location of driver:
http://www.astro-physics.com/products/accessories/software/Serial_USB/FTDI_driver_nd4.pdf
b) Install third party software (Starry Night, TheSkyX, MaxImDL, etc.)
c) Adjust software settings - follow the appropriate Workow documentation that follows in this guide
d) If using the Keypad along with a computer, set the Keypad to AutoConnect=EXT and power cycle the mount in
order to lock in the change.
2. Assemble the mount. Reference your Mount Manual.
3. Balance the system. Reference your Mount Manual.
4. Polar align the mount – at least roughly. (If using the daytime routine, move this step to after the mount is initialized. If
using the RAPAS, do it before initializing.)
5. Place the system into a pre-dened AP Park position for initialization. Reference the positions shown at the end of this
Quick Start Guide.
6. Power up the mount and connect with your primary control software. Use the primary control software to initialize
the mount. Start out from the park position chosen in #5 above. Your other initialization settings will have been set
already in step #1.
a) If using APCC, always start it and connect with it rst.
b) If the AP V2 Driver is your primary control software, it must be started with a client program.
7. Connect other software that you will use with the mount.
8. After nishing your night’s observing (or day’s solar observing) it is best to park the mount into your chosen Park posi-
tion using either the AP V2 driver or APCC, rather than Third Party software if you are using a PC for mount control.
9. Power down the mount.


1. Loosen all the R.A. and Dec. clutches so that the scope can be moved freely with your hands. Moving the scope into a
Park 3 position will provide additional safety for this procedure.
2. Command the mount to go to Park 3 using either the Keypad or a computer (whichever you have been using for the
evening). While the motors are moving, hold the scope with your hands so that it remains safe.
3. When the motors both stop, use your hands and put the scope into Park 3 (use your eyes to get close) and then tighten
all the clutches.
4. That’s it...you’re done! Orientation has been restored to the universe! When you go to your rst object you’ll need to
tweak the centering and do a ReCal, but you’ll be close.

13

Assemble Pier (purchased separately)
Begin by assembling the portable pier at the desired observing
location. Take note which direction is north. (These instructions
are for the Astro-Physics Portable Piers. For other piers, please
follow the manufacturer’s instructions.)
1. Slide the three legs onto the nubs of the base and rotate
the assembly so that one of the legs points toward north (or
toward the south if in the southern hemisphere).
2. Place the pier post on the base, orienting the eyelets for at-
taching the turnbuckles directly above each leg.
3. Attach the tension rods. The turnbuckles should be drawn
tight until the whole assembly is sti󰀨 enough to support your
weight without movement.
Attach Polar Axis Assembly to Pier
In order to track the motion of astronomical objects, the Polar Axis must be positioned so that an imaginary line drawn
through the center of the axis points toward the celestial pole. Refer to the diagram at the front of this manual for a
graphical representation. At this stage, you want to position the pier so that it points roughly north.
1. Adjust the Azi-
muth Adjuster so that the Azimuth Adjuster Block is
centered. This will allow adjustability when it comes
time to polar align the mount. See photo below.
2.  Set up your pier so that the counter-
weight shaft is oriented above the north pier leg. It is
important when using a portable pier to face one leg to
the north so that the o󰀨set weight of the counterweight
shaft and counterweights do not create an unstable
balance.
3.  Carefully set the 1100GTO Right Ascension Axis / Polar Fork assembly into the open top
of your pier, or into the 1100 Flat Surface Adapter (119FSA), if are using one.
4.  If the side thru-holes in the pier or 119FSA are not perfectly lined up with the tapped holes in
the mount’s Pier Adapter base, rotate the mount. Be sure that the tips of the two azimuth adjuster knobs are tightened
against the azimuth adjuster block; otherwise, the base will rotate making it di󰀩cult to line up the holes.
5.  When you have the holes lined up, fasten the mount to the pier top or to the Flat
Surface Adapter using six 5/16-18 X 5/8” socket button head cap screws and 5/16 at washers. Note that the washers
have a sharp edged side and a softly rounded side. Be sure that the rounded side faces the paint or anodizing of the
pier so that no marring of the nish occurs. Be sure to start all six cap screws (with their washers) before tightening
any of them. Then, snug all six cap screws down before nally tightening them all securely.
  Although it is not important that a German equatorial mount be level to achieve polar alignment, it
does make it easier in that an adjustment to altitude or azimuth a󰀨ects only the direction to which you are making the
adjustment. If the mount is not level, you will be able to achieve alignment, but when you make an adjustment to azi-
muth, for example, you are actually making a simultaneous adjustment to both azimuth and altitude when out of level.
Note that if you are using the Right-Angle Polar Scope, it is required to be level in the east-west direction in order to
achieve accurate polar alignment. Level the mount...you’ll be ahead in the game!
  These were not installed prior to shipping due to packaging restrictions.
Please reference the prior assembly diagrams for part identication and placement.
Azimuth Block
Azimuth Adjuster Knobs
Azimuth Threaded
Push Rod

14
Latitude Adjustment for 1100GTO German Equatorial Mounts
The 1100 mount accommodates a latitude range from 0 to 78 degrees and 90 degrees. The Altitude Adjuster Bar allows
for gross latitude ranges, while the Adjustment Knob is used to provide the precision adjustments when polar aligning. The
Altitude Adjuster Bar is positioned into one of nine slots which provide an overlapping latitude range.
This altitude bar is very convenient when travelling to remote sites, as it allows you to transport your mount in the more
compact, zero-latitude position. You can change to your remote site’s latitude in one quick motion of the altitude bar.
How to change the position of the Altitude Adjuster Bar
1. Due to the portable size of the 1100GTO mount, this
procedure can be done with the mount fully assem-
bled, or can be made easier using only the R.A. axis.
However, DO NOT attempt to make these adjust-
ments with an instrument or counterweights mounted.
2. The mount’s Polar Axis is held in place between the
two side plates of the Polar Fork. The axis pivots on
custom shoulder bolts located towards the rear of
each side plate. These bolts should not be loosened
when making altitude changes to the mount.
3. Loosen all four Polar Axis Lock Knobs about 1 turn.
4. Tilt the R.A. axis upwards and hand tighten the lock
knobs so that the axis does not drop while you are
repositioning the Altitude Adjuster Bar.
5. Note that the Altitude Adjuster Knob is attached to a threaded rod that travels through the Altitude Adjuster Bar. Turn
the knob so that you see about half of the threaded rod protruding from both sides of the bar. This will allow you to
move the mount fully within the altitude range. The slots are positioned at 9 degree increments and the threaded rod
has 10 degrees of travel. They represent the following altitudes:
a) Slot 1 - 0-10° center: 5°
b) Slot 2 - 10-20° center: 15°
c) Slot 3 - 19-29° center: 24°
d) Slot 4 - 28-38° center: 33°
e) Slot 5 - 37-47° center: 42°
f) Slot 6 - 46-56° center: 51°
g) Slot 7 - 55-65° center: 60°
h) Slot 8 - 64-74° center: 69°
i) Slot 9 - 73-78° Note - it is necessary to remove the
Polar Axis Lock Knobs and shift the mount into its 90°
position in order to utilize this upper slot. Once done,
lower the axis and restore the knobs.
6. Shift the Altitude Adjuster Bar into the correct slotted position. Note that the re-positioning is done so quickly and easily
that trial and error positioning is inconsequential. There is a degree scale on each Polar Fork with a corresponding
indicator line on the beveled edge of the worm wheel housing to assist you. See photos above.
7. Note that the threaded rod has a rounded end. Also observe that the underside of the R.A. Axis has an inset socket.
When you loosen the Polar Axis Lock Knobs and lower the polar axis be sure that the rod comes to rest fully seated in
this socket. A little wiggle of the adjuster knob will ensure its proper seating.
8. Turn the Altitude Adjustment Knob to raise or lower the Polar Axis to your approximate observing latitude (note the
previously mentioned altitude lines on the side). Tighten the Polar Axis Lock Knobs with nger pressure only. You do
not need to tighten with the hex key.
Insert
Rod
Socket
Altitude Knob
Altitude
Slots

1100GTO shown in photo
DO NOT Loosen
Pivot Bolt
Altitude
Adjuster
Position
Slots (9)
Altitude
Adjuster
Bar
Latitude
Degree Scale
Polar Axis
Lock
Knobs

15
9. Later, as you adjust the mount’s altitude when polar
aligning, you should always make the nal adjustments
pushing upwards. Additionally, the lock knobs should
be increasingly tightened as the nal adjustments are
made.
 Rough polar positioning of the mount
and pier should be done with the R.A. axis only since you
will be making major adjustments to level the mount, aim it
north and set the elevation. The remainder of the mount,
telescope and counterweights will add considerable weight
and require more e󰀨ort when positioning. Later, you will
do your actual polar alignment with telescope and counter-
weights attached, but the adjustments will be comparatively
small and within the range of the altitude and azimuth ne
adjustments. An inclinometer and a compass adjusted for
magnetic declination at your location (or these functions on
a smart phone App) are recommended.

One of the unique design features of the 1100GTO mount is its ability to be placed into a 90° Alt-Azimuth position. This
allows specialized functionality for research applications, as well as terrestrial viewing. In order to achieve maximum
stability, it is important to maintain the center of gravity directly above the pier. This requires that the R.A. axis be reversed
in the polar forks. The change over is outlined below in illustrations and description. 

1. Remove telescopes and counterweights before beginning this orientation change. It is also necessary to separate the
Dec. axis so that you are only working with the R.A. axis and forks.
2. Remove all four Polar Axis Lock Knobs.
3. Tilt the axis upward to its maximum balanced position and remove the Altitude Adjuster Bar and set aside. The axis
must be held in place as there is no way to secure it.
4. While one person holds the R.A. axis, have the other person remove the two shoulder bolts that are the Pivot Bolts for
the axis. Remember that the full weight of the axis will need to be supported.
5. Lift the axis straight
up and out of the
polar forks. Walk
around to the other
side of the mount so
that the R.A. axis can
then be lowered back
into place, but now
facing the other way.
6. Align the Pivot Bolts
with their respective
threaded holes and
screw into place. Do
not tighten them until
both bolts have been
fully threaded and the
axis rotated slightly
back and forth to ensure that it is properly seated. Now tighten the bolts fully.
7. Replace the four Polar Axis Lock Knobs. Notice that they will all be in the lower channel. Two of the knobs are placed
into the available threaded holes that were previously unused. Use a bubble level to position the axis and secure the
knobs tightly using a 1/4” hex key. You now have an Alt-Azimuth mount.
 We do not oer software for the 1100GTO mount congured in the Alt-azimuth mode at this time.
It will be necessary for you to write your own command protocol. However, it can be used manually via button
moves.
(Not Used)
Indicator Line

16

Understanding Cabling Dierences in Non-AE and AE Mounts
O󰀨ering the option of Absolute Encoders to the 1100GTO mount presented some design challenges. Apart from creating
a robust and high precision system, it was important to nd an elegant and aesthetic solution that would minimize cable
clutter and also take advantage of the mount’s internal cabling feature. A brief summation of the cabling di󰀨erences
between the standard 1100GTO mount and the Absolute Encoder version of the 1100GTO mount (1100GTO-AE and
1100GTO-AEL) follows.
1100GTO
The 1100GTO mount (standard version) uses our traditional Y-cable design of the servo motor cable to connect the R.A.
and Dec. motors to the GTOCP4 control box. This Y-cable (S1100GYCR) is proprietary to the 1100 mount and cannot be
used with any other mount. Its longer Dec. branch is run internally through the R.A. axis and then exits a cable port on the
front of the Dec. axis. It then connects to the motor box. The cable port has a slotted cover that will slide shut and protect
against dust and insects. This cable is user installed.
Additionally, please note that there is a slotted access port
cover on the rear plate of the R.A. polar axis though which
the lower end of the Dec. cable can pass.
The R.A. servo cable branch will connect to the R.A. motor
box externally.
Finally, the connector which joins the two servo cable
branches will be attached to the GTOCP4 box at the
connector marked “motors”.

The 1100GTO-AE and 1100GTO-AEL Absolute Encoder versions of the mount utilize
a more complex cabling system that communicates encoder Readhead information
as well as the motor servo information. We call this cable system the X-cable system.
The Dec. AE Readhead connects to the motor
box via a 9-pin DE-9 connector. The encoder
information, along with the Dec. motor servo
information, is communicated via a single cable
that connects and looks like the cable described in
the section above. This cable is pre-installed at the
factory.
From the round connector on the motor box the
servo cable runs through the cable port with the
slotted cover and then internally through the R.A.
axis, exiting through the slotted cable port on the rear plate of the R.A. polar axis.
Unlike the Y-cable described above, this cable screws into to a junction box on the
underside of the polar axis.
The junction box sorts the Absolute Encoder and servo motor information/wiring
of both axes. It has three cables hard wired into it. One cable on the east side
(northern hemisphere) goes to the R.A. motor box for communication to both
the AE Readhead and the R.A. motor
externally. The other cable on the east
side connects to the GTOCP4 connector
marked “encoder”. The nal cable exiting
the junction box from the west side
goes to the GTOCP4 connector marked
“motors”.
AE Readhead
Cable
Servo Motor
Cable
R.A. Motor Cable
Dec.Motor Cable
Junction
Box
Servo Motor
Cable
AE Readhead
Cable

17
Assembly of R.A. and Dec. Axes
One of the many features of the 1100GTO mount is internal cable routing. Internal cabling adds protection and
convenience. It eliminates many concerns, such as cable-snags and excessive dew exposure to electrical parts, whether
the telescope is in the backyard or at remote sites. 
If you choose not to utilize internal cabling for your 1100GTO
(without encoders), you may custom order a longer Y-cable
that will allow you to run the cable externally in the more
traditional way of the 900 and 1200 mounts. In this case, you
would pass the cable around the left (west) side of the mount
when attaching it to the Dec. servo connector. The low prole
design of the 1100 clutch knobs reduces the chance of a
cable snag, but know that it is possible.
If you route your Dec. Servo Cable through the mount, then
it is important to remember to detach the connection when
separating the mount’s two axes. Otherwise, you will damage
an expensive cable and risk pulling the Dec. axis from your
hands as you start to walk away. These procedures apply
to all three versions of the mount, with or without absolute
encoders.
Assembly Procedure




1. Ensure that the R.A. (polar) axis is securely attached to its pier before proceeding.
2. The Dec. Servo and Readhead Cable (Absolute Encoder mount) is pre-routed through the R.A. axis. The Dec. Servo
Cable (Y-cable of non-AE mount) will need to be routed through the R.A. axis by the user. Note that there is also a re-
movable Cable Router provided with the mount which serves the purpose of keeping any internal cables out of the light
path of the polar scope. If you will not be using a polar scope, then you have the option of not using the cable router.
3. Position the Dec. Servo
Cable along the side of the Cable
Router (if used) and loop it back
into the center of the insert. This
will keep the cable out of the way
when attaching the Dec. axis to
the R.A. axis. See photo at top
of page.
4. Rotate the R.A. axis to the posi-
tion shown in the illustration with the two clutch knobs at the top
and the single clutch knob at the bottom. Note that the channels
line up vertically and that the Dec. lock knob dovetail insets are at
the bottom. See photo at top of page.
5. During shipment, the Dec. axis lock knobs will be fully screwed
into the Dec. axis. You will need to back these out (approximately
8+ turns) until the tip is fully retracted.
6. Position the Dec. axis above the R.A. axis (see photo at left),
then hook the top of the dovetails of the two axes together and tilt
the axis into place while giving a light wiggle so as to properly seat
them (shown by arrow “A”).
7. When the Dec. axis is fully seated, hand tighten the two lock
knobs.
8. There are two 1/4” counter-bored holes (one on each side) on
the front of the Dec. axis. Insert a 1/4-20 x 5/8” socket head cap
B
OFF
A
ON
Declination
Axis Lock
Knob (2)

Altitude
Adjuster
Knob
Dec. Lock
Knob
Dovetail
Insets
Clutch (3)
Clutch
Knob
(3)
Dec.
Servo
Cable
Cable
Channel
(3)
Cable
Router
Polar Scope
Sighting Channel
Channel (2)

18
screw into each of the holes and tighten. These screws provide additional rigidity and security for the heavier capacity
of the mount. When in public observing locations or when children are present the lock knobs could be loosened by
accident. This is an optional procedure. It is important that you tighten the lock knobs fully before adding these
screws, so that the dovetail of the Dec. axis is properly seated.
9. Remove the Dec. Counterweight Adapter by unscrewing it. If it is too tight to turn by hand, you may insert a hex key
into one of the two holes at the side of the adapter in order to gain leverage. See photo in disassembly procedure
below.
10. Reach inside the axis and retrieve the Dec. Servo Cable that was inserted into the center of the R.A. axis Cable Router.
Feed the cable out through the cable port with the slid-
ing cover raised and attach to the Dec. motorbox servo
socket. Note: Previous version of the mount is shown.
See photo at right.
11. Once all of your cables are in place, lower the cable port
cover and replace the Dec. Counterweight Adapter. It is
not necessary to take great pains to tighten the adapter
since it will be tightened as the counterweight shaft is
secured.
12. Thread the counterweight shaft into the Dec. Counter-
weight Adapter. Ensure that the Delrin washer is in place
on the threads of the shaft so that the shaft will be easier
to remove later.
13. Attach the Dec. Top Plate to the axis and lock it in place
by hand tightening the two lock knobs. You may wish to
place and tighten the two 1/4-20 x 5/8” socket head screws that provide additional attachment security. It is important
that you tighten the lock knobs fully before adding these screws, so that the dovetail of the Dec. Top Plate is
properly seated.
Disassembly procedure
1. Essentially, one reverses the assembly procedure. Start by removing the telescope, counterweights and counterweight
shaft.
2. Remove the Dec. Counterweight Adapter by unscrewing it. If it is too tight to turn by hand, you may insert a hex key
into one of the two holes at the side of the cap in order to gain leverage.
3. Disconnect the Dec. Servo Cable at the motorbox connection as
shown in the illustration (see above illustration). Feed it back through
the cable port and tuck it back into the center of the R.A. axis for
safety and to prevent damage.
DO NOT FORGET

4. Replace the Dec. Counterweight Adapter.
5. Remove the 1/4-20 security screws from the lock-down holes (if they
were used) and loosen the two Dec. axis locking knobs 8+ turns.
6. Separate the two axes as shown by letter “B” in the illustration in the
assembly section.
7. For transport and storage, we recommend re-tightening the Dec.
locking knobs.
8. Place the R.A. axis in the zero-degree altitude position for compact
transport.
Leverage
Hole (2)
Dec. Counterweight
Adapter
Dec. Cable
Port Cover
Note:
Remove Counterweight
Shaft before Adapter
Dec. Servo Cable Connection
Dec. Servo Cable
Dec. Cable
Port
R.A. Axis Center
Dec. Counterweight Adapter Removed

19

It has become more important than ever to nd ways to manage cable routing. We now have the lure of imaging and with
it the addition of accessories requiring power and computer connectivity. Apart from multiple dew heater cables, we now
have CCD cameras, color lter wheels, camera rotators, motorized focusers, autoguiders, adaptive optics units and the
list goes on... All these devices have power cables and USB or serial cables that need to be managed. To simply allow
all these cables to dangle would make your telescope look as though it is having a very “bad hair day” and it would invite
disaster. At the very least, dangling cables create exure that results in bad star shapes in your images; at worst, they
cause cable snags and damage to your equipment.
We have gone to great lengths in designing and engineering the 1100GTO mount to accommodate advanced cable
management. This job was made more complicated by our philosophy that our mounts should be portable and the two
axes need to be able to be separated for the ease of setup and transport by our customers. Since our mounts can be
portable, we needed the ability to use a polar alignment scope for quicker set up time and alignment accuracy. We have
succeeded in our challenges. The 1100GTO allows you to pass all your cables through the mount while maintaining a
visual path for a polar scope. It is the most advanced cable management system on the market today.






Preparation
 The key to good cable routing is good planning. Every imaging setup is somewhat unique. The equipment
is di󰀨erent and the selection of devices depends upon the type of imaging that interests you and the level to which you take
it. As systems become larger and more complicated, the greater the importance of planning and organizing. It is not as
simple to add a cable later since you may have to disassemble your system to do so.
It is best to lay out your imaging system and connect all the wiring so that you have a good idea which cables need to be
routed through the mount. This can be done by spreading your devices on a table; they do not actually need to be set up
on a telescope. This will also allow you to have an idea about cable length, if there are choices to be made. Once you
have all your devices connected and know that you are not forgetting an important power cable or other critical necessity,
you are set to begin the actual process of routing your cables.
You may wish to consider reducing the number of cables needed by running a single power cable up through the mount
to a power distribution hub, such as a RIGRunner, on top of your instrument package. Similarly, you can run a single
communication cable through the mount to a communication hub, such as an ICRON Ranger, located at the top. Using
these hubs can simplify and improve the quality of your setup.
The Basics
The 1100GTO mount has some very unique features that assist you with your cable management. Starting at the top of
the mount, you notice that there is a removable Dec. Top Plate. This plate allows you to attach various dovetail saddles
and specialty plates for the many, varied telescope systems to be found today. Notice that it has two cable channels
machined into it. It is also removable via a unique and powerful dovetail system so that you have unobstructed access
to the internal central routing core of the mount. The bottom of the Dec. axis also has a removable Counterweight Shaft
Adapter that unscrews to allow access internally so that routing cables can be done more easily.
The R.A. axis has a clever Cable Router which is removable. This router serves the dual purpose of organizing the
cables while preserving a clear light path for the polar scope. In a permanent observatory setup, it is not necessary to use
the router, though it may be left in place, as it will not restrict the number of cables that can be run. It is designed to be
removable so that cables can more easily be routed through the mount and then replaced to secure the light path.
The nal part of the internal cable routing system is the Cable Access at the bottom of the rear R.A. Plate. This access
has two covers that are removable by undoing the socket head cap screws securing them. Once removed, cables with
connectors as large as RS-232 cables can be fed through the opening. It is always a good idea to feed the largest
connectors through rst before moving on to the smaller sizes. If you do not plan to use a polar scope, you have the
additional option of routing the cables through the central opening.
The Specics
What follows are more detailed instructions for installing your cable package into the 1100GTO. You will, of course,
have to tailor the instructions for your own particular needs. These instructions are for the routing of auxiliary cables for
cameras, dew heaters, focusers and other devices that are not a component of the 1100GTO. The mount’s own cables are