ASTRO-PHYSICS
1100GTO German Equatorial Mount
with
GTOCP4 Control Box
Auto-Adjusting Motor/Gearboxes
Your choice of three models:
1100GTO German Equatorial Mount (1100GTO)
1100GTO German Equatorial Mount with Absolute Encoders (1100GTO-AE)
1100GTO German Equatorial Mount with Extended Temperature Range Encoders (1100GTO-AEL)
* * Save $1,000 on Mounts with Absolute Encoders * *
1100GTO |
1100GTO-AE or -AEL |
Read the Sky & Telescope July 2017 review by clicking
on the link above.
New in 2016
Throughout the years, the Astro-Physics design team has sought to continually improve our product line, particulary as the technological demands for ever more precise equipment has increased.
GTOCP4 Control Box![](CP4-w--HProduct.jpg)
The GTOCP4
Control Box offers multiple connection options to suit your
requirements including wifi, ethernet, USB and serial ports. In addition to
all the features carried forward from previous control boxes, the
GTOCP4 applies safety slew logic to all slew commands. Future firmware updates
will be available via direct downloads.
Auto-Adjusting Motor/Gearboxes
Our new motor/gearboxes were designed to be more responsive for precision astro-photography, while at the same time making it super easy to use and adjust. Here are some key features:
- Spring-loaded worms maintain full contact under all
guiding and slewing conditions
- Automatic setting for worm mesh requires no adjustments over long time periods
- Very easy to do precision balance by new mechanism which allows full backing
off the worm from the worm wheel
- Very low backlash geartrain eliminates Dec reversal delays
and provides high position accuracy during guiding
- Geartrain components are made with high-strength stainless
alloy for extremely low wear even with continuous slewing applications
- All worms are tested to meet stringent periodic error specs. Error is measured with PEMPro and the resultant compensating curve is loaded into the servo controller so you can use the PEM function to remove 90% of the variability even in non-encoder mounts.
Why an 1100GTO?
This medium-sized mount travels eagerly to star parties
where your 12V battery will keep it running all night or is content to stay
at home in your observatory, ready to image while you sleep.
We offer three versions of this mount: 1100GTO, 1100GTO-AE
and 1100GTO-AEL. The latter two versions include the Standard Temperature Absolute
Encoders or the Extended Temperature Absolute Encoders, respectively. If you
order the 1100GTO without the absolute encoders, you will be able to purchase
them at a later date to install yourself.
This webpage discusses the features that are common to all
three mount versions, except where indicated.
The 1100GTO was introduced at the Northeast Astronomy
Forum (NEAF) in Suffern, NY in April 2013. In the video below, George Whitney,
from the Astro-Physics Technical Support staff, explains key features of the
1100GTO in an interview conducted by Dennis DiCicco, Sky & Telescope editor.
We also invite you to view the entire video for demonstrations of these additional
exciting products: 1600GTO German Equatorial mounts with discussion of the Absolute
Encoder System used in both the 1100GTO and 1600GTO mounts, Right-Angle Polar
Alignment Scope, the 10 x 60 Vario Finder with Quick Release Guider Bracket and
the Astro-Physics Command Center (APCC) software.
Improved Features Compared to the 900GTO, its Predecessor
Since the introduction of the 900 German Equatorial Mount
in the mid 1990s, it
has evolved several times to meet the increasingly greater technological requirements
of our customers. The new 1100GTO is the next step in that evolutionary process
offering increased capacity, ease of setup and use and enhancements to make
your imaging sessions more productive and enjoyable. The modular design
allows you to easily upgrade your mount with limit switches or absolute encoders
sometime in the future.
Here are some changes that you may find useful in addition
to the GTOCP4 and Auto-Adjusting Motor/Gearboxes discussed abovel:
- Dec. axis gear increased to 7.2" (183mm) for
higher payloads and more stability.
- Azimuth adjusters have been repositioned to the
rear of mount which
allows you to make minor corrections quite easily without reaching or moving
around the mount. Since the knobs are now in front of you as you look through
the polar scope, the graduations can be more easily seen as you dial in your
position.
- Built-in precision-rotating pier adapter is
now included and not purchased as a separate item.
- Major altitude adjustments are extremely
quick and easy to make by simply shifting the position of the altitude adjustment
bar into a new slot. The large "captain's
wheel"
knob, convenient to grasp and turn, performs the fine adjustments. If you travel
to a star party at a different latitude, the changes to your setup are quickly
made and allow you to transport the RA assembly in a more compact, zero
degree latitude configuration.
![](1100_PlaneWave.jpg)
- Altitude range now
extends from 0-78 degrees in its normal configuration. The Hi-Low
Wedge is no longer necessary.
- Right-Angle
Polar Alignment Scope (optional)
can be used without the need for an additional adapter.
- Unobstructed Dec. opening for Polar Alignment Scope allows
greater field of view for both the Astro-Physics Right-Angle or the Losmandy
Style Polar Alignment Scopes.
- Internal routing of motor cables to remove
the possibility of snagging.
- Easily route additional cables through
the large openings in the R.A. and Dec. axes. The top of the Dec. axis separates
so that you can add cables with large connectors.
- Right-angle connectors are used where
applicable to reduce strain on the cables.
- Improved clutch system with NO clutch plugs that
can potentially deform over time if they are overtightened. This issue has
been eliminated.
- Clutch can be set to any amount of engagement up
to complete locking of the axes so nothing can slip.
- Control box mounted vertically rather
than on the top to reduce the possibility of moisture getting into the electronics
in damp environments.
- Precision bubble level built into mount
base.
- Stainless steel lanyard post on either
side of base to hang your keypad.
- Greater capacity to provide a rigid platform
for fairly large instruments or side-by-side setups.
- Absolute Encoder option to provide error-free
tracking, software readable absolute position, customizable home and limit
functions for robotic imaging. This option can be installed when you purchase
your mount (order either the 1100GTO-AE or 1100GTO-AEL version) or you can
purchase the option as an upgrade kit when you are ready to take advantage
of its capabilities.
- Limit/Homing Switch option to provide home and
limit functions using a mechanical switch (does not use the absolute
encoders). This option will be available in the future.
Versatility
Portable.
Extremely solid, rugged,
high payload mount, yet the equatorial head comes
apart into two components
for hassle-free field setup.
Operate with 12V battery.
You can take it to the darkest skies and power it with a commonly available 12V battery. In the observatory, we suggest a minimum 5 amp filtered,
regulated power supply like our 13.8-volt, 5-amp Power Supply (PS138V5A). For a heavy payload in cold conditions, we offer a 25 Amp Variable Volt Power Supply (PSVPW25A).
Clutches.
Allow manual operation if power is not available. Use
the clutches to easily balance your setup, then lock the R.A. and Dec.
axes so that they cannot move when the motors are engaged.
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Image past the meridian.
The mount will track and guide well past the meridian
in either direction if the object is located such that the telescope will clear
the pier. This allows the user to set up the mount for a long series of exposures
without stopping in the middle to flip sides. One can start the telescope under
the mount while pointing at an object in the eastern part of the sky and track
it all the way deep into the western sky. This is very useful for long exposure
H-alpha or in cases where a large number of individual exposures are needed for
stacking. This feature of our GTO mounts has been a real customer favorite:
The 1200GTO's ability to continue tracking when past the meridian is an absolute winner for me. It avoids meridian flips (=imaging time) and reduces the need for expensive rotators. Jan Rek.
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. . . I love the ability to place the OTA on the "wrong side" of the mount when starting an imaging session ("premature meridian flip") and which I have used extensively. This feature is pure INGENUITY! Anthony Ayiomamitis.
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Easy alignment for critical
viewing.
You can align the 1100GTO using setup routines
in the optional keypad for most non-critical observing. Our optional Right-Angle
Polar Alignment Scope will allow you to quickly zero in on the pole or
the polar alignment routine in PEMPro (included) will guide you through the
process. You can even align the mount during the day with our clever Daytime
Polar Alignment Routine (outlined in the Keypad Manual) for solar observing,
viewing the planets at twilight, or just getting a jump start on a long night.
Multiple Options for Controlling your Mount in the Field or in Your Observatory
You have your choice of the GTO Keypad (optional),
which is a full-featured handheld computer, PC computers using a wide variety
of software with or without our ASCOM driver, Mac computers or even your mobile
smart device (like your iPhone or iPad). Follow this link to
discussions of GTO control
options.
Mechanical Features
Precise Mechanical Fabrication
Using modern CNC machining techniques, we make all components to a high precision level, which results in a final package that is solid and accurate in all respects. The critical angles are accurately machined so that the mount is orthogonal to a very high degree. This results in pointing accuracies well below 1 arc minute for a properly aligned mount. Massive thrust bearings and preloaded shaft bearings provide excellent stability under all imaging situations.
Easy to Adjust and Maintain
The design of the 1100GTO is straightforward with modular
construction. We provide information in the
Technical Support section of our website pertaining to typical adjustment issues.
Components are modular.
All electronics including the GTOCP4 control box, motors,
gearbox or cables can be removed for servicing. The RA and Dec axes can be shipped
separately, if needed.
Mechanical Specifications
Construction |
All CNC machined aluminum bar stock, stainless steel, brass;
stainless steel fasteners |
Finishing and Assembly |
Every part is hand-finished and inspected. All assembly is done by hand, by highly skilled mount assembly staff. |
Worm wheel - R.A. & Dec. |
7.2" (183 mm), 225 tooth aluminum |
Worm gear - R.A. & Dec. |
0.71" (18 mm) diameter |
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 |
Azimuth adjustment |
Approximately 18 degrees (+/- 9 degrees from center) |
Counterweight shaft |
1.875" (47.6 mm) diameter x 16.5" (419 mm) usable length, incl. large machined safety stop knob. Optional 8.675" (220 mm) shaft extension available. Weight 13 lb. (5.9 kg) |
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 |
Approximately 110 lb. (50
kg) of scope and accessories, depending on
length. Recommended for refractors up to 200 mm, 14-16" Cassegrains, Ritchey-Chretiens
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 |
Refer to list of suitable mounting plates below |
Pier adapter base diameter |
7.730" (196.3 mm) Base. The base is an integral part of the mount and azimuth adjuster. |
GTOCP4 Servo Drive System
Like the previous GTO mounts, the GTOCP4 drive
system uses a high-quality Swiss DC servo motor controlled by a microprocessor
to an accuracy of 0.05 arc-seconds per step. Tracking is very smooth, noticeably
smoother than any stepper motor drive or inexpensive servo motor. The system
can be accurately controlled over a speed range of 4800:1, which allows 0.25x
sidereal for manual guiding to 1200x sidereal for 5 degree per second slewing.
The circuit draws approximately 0.5 amps when tracking the stars, 2.5 amps
with both motors slewing and requires only 12 volts to operate. The servo drive
will satisfy the requirements of the sophisticated, advanced astro-imager,
yet is easy for the casual, visual observer to use.
Gear Accuracy and PE Performance
The heart of this mount is a precision gearbox using
custom high-quality fine-pitch gears, coupled to a highly accurate worm and worm
wheel. These parts are manufactured and assembled at our facility and individually
tested to meet or exceed our periodic error specification of 7 arc seconds (+/-
3.5 arc sec.) before introducing any periodic error correction. The PE is smoothly
variant with extremely low ripple or moment to moment error. In contrast, mounts
that use commercial gearboxes have very small spur gears with tiny teeth
and too few of them. This generally causes ripples in the tracking rate which
are difficult to guide out.
Each mount is rigorously tested on our specialized periodic error tester. Only
mounts that provide an accuracy of 7 arc seconds or better will pass this inspection.
If the mount exhibits greater error, the substandard part is identified, replaced
and the mount is retested.
Pre-loaded PEMPro Curve
As mentioned above, the spec of 7 arc seconds (+/- 3.5
arc sec.) is the maximum native mechanical error inherent in the mount's RA axis
WITHOUT any software correction. In order to optimize performance even further,
we use a special version of Ray Gralak's PEMPro developed specifically
for our test equipment. We generate a unique PE curve for each mount that we
program into each GTOCP4 Control Box. Simply use the optional Keypad or your
Astro-Physics software (ASCOM V2 driver, PulseGuide or APCC) to turn the PE Correction "on" and
you will see results significantly better than our published 7 arc second spec
without additional PEMPro runs! However, you may use PEMPro to further refine
your PE, if you chose to do so.
1100GTO-AE or 1100GTO-AEL: If you purchase either
of these versions with absolute encoders, the final in-house PEMPro run will
utilize the corrections of the absolute encoders and the values will be stored
in the GTOCP4 Control Box.
GTOCP4 Control Box
The GTOCP4 Control
Box contains all of the circuitry to drive the two servo motors and the logic
required to navigate the sky. It can be easily removed from the mount, if required.
The 1100GTO uses the same GTOCP4 Control Box as the 1600GTO and Mach1GTO (the
control box is black-anodized for the latter mount).
In fact, the control boxes for all three mounts are interchangeable with one
another in an emergency. However, the absolute encoder function is only available
in the control boxes sold with those mounts. Extensive information regarding
the GTOCP4 can be found here.
GTO Keypad (optional purchase)
The Keypad is
a self-contained computer that allows you to control all essential telescope
functions and includes an extensive database of objects. We have designed the
interface and firmware to be as intuitive and easy to use as possible, while
filling it with terrific features to make your observing session productive and
pleasurable. Click here for
detailed information regarding features and functions of the Keypad.
Prior to mid-October 2015, the Keypad was included as part of the mount. However,
some of our customers own multiple AP mounts, but only use one at a time. For
them, one keypad is sufficient. Others only control their AP mounts with their
computer and do not use their Keypad. So, we decided to offer the Keypad as an
option. As a result, we were able to reduce the price of the mount accordingly.
Many people do not want to bother with a computer in the field and like the handiness of the Keypad and its ability to operate in very cold temperatures. They will choose to purchase the Keypad.
Optimized for Astronomy
Astro-Physics mounts and the Astro-Physics GTO Servo Control System are designed
from the outset as tools for celestial observing and imaging. These
mounts do not have any military or defense applications. Applications like
missile, airplane, or very low earth orbit satellite tracking require faster
tracking rates and more rapid changes to those tracking rates than our mounts
allow. Note that the ISS is generally within the mount’s
tracking rate capabilities.
During the 2016 Northeast Astronomy Forum (NEAF),Roland
Christen of Astro-Physics demonstrated some of the functions of the Auto-Adjusting
Motor/Gearboxes, the Absolute Encoders and GTOCP4 Control Box. Although
the 1600GTO mount is shown, these same features are available for the 1100GTO. Dennis
DiCicco, editor of Sky & Telescope magazine,opens the interview with a discussion
of the 17" f8 Flat Field Astrograph.
GTOCP4 Servo Drive System Specifications
Electronic components |
Rated for industrial and automotive applications |
Motors |
Zero-cogging Swiss DC servo motors, enclosed in machined aluminum housing |
Motor encoder |
2000 tic quadrature yielding an effective resolution of 0.050 arcseconds per tic |
Motor reduction gear train |
57.6:1 gear reduction through a custom built set of large diameter, fine-toothed, precision, spur gears for vastly superior performance |
Servo Motor Control Box |
GTOCP4 Control Box, removable |
Hand-held computer (optional) |
GTO Keypad to control all mount functions. Includes extensive databases and tour features in a simple, intuitive interface. Firmware updates via the internet |
Power consumption |
~ 0.3 to 0.6 amps at 13.8 volts - tracking
~ 1.3 to 2.5 amps at 13.8 volts - both motors slewing at 1200x |
Power requirements |
Nominal 12 volt DC supply at minimum of 5 amps continuous |
Periodic error |
+/- 3.5 arc seconds or less in one worm
cycle (6.4 minutes); native, prior to any error correction |
Maximum slew speed |
5 degrees / second |
Absolute Encoders - 1100GTO-AE and 1100GTO-AEL
![](../1600gto/175-M106-600secL-thumb2.jpg)
10 minute
unguided exposure
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The 1100GTO mount has been designed
and engineered to accomodate extremely precise Absolute
Encoders. These are the same encoders as are used on the 1600GTO.
Absolute Encoders allow the mount to know its exact location regardless
of accidental software errors and will allow its recovery. This is particularly
important in remote setups. Furthermore, they virtually eliminate periodic
error, reducing it below 0.2 arcseconds in our tests. If you order the
1100GTO-AE or 1100GTO-AEL, the R.A. and Dec. encoders will be installed
and fully tested with the mount prior to shipment.
However, if you purchase the 1100GTO without
encoders, you may purchase the Absolute Encoder Kit at some point in
the future and install them yourself.
Check
out the 10 minute (600 seconds) unguided exposure
by clicking on the thumbnail to the left. Note that this image
was taken with the 1600GTO, but as mentioned earlier, the same encoders
are used on the 1100GTO, so the performance is representative. |
Flexible Control with Your Keypad, Computer or even your
Mobile Smart Device!
PEMPro
Software, Version 2
PEMPro (Periodic
Error Management Professional), Version 2, by Sirius Imaging is included with
this mount. It is a very powerful Windows software application that allows you
to correct your mount's periodic error, polar alignment and backlash using your
CCD Camera or Webcam to dramatically improve tracking and guiding.
As mentioned previously, our extensive testing procedures
include several PEMPro runs so that your new mount will perform with optimum
PE correction out of the box. Simply use the Keypad, the ASCOM driver or APCC
software to turn PE Correction "on." Although you
will not need to use PEMPro when you receive your mount, you may wish to do a
PEMPro run at a later date after the worm gear has run in. Depending on usage,
re-measuring error and re-loading periodic error correction from one to four
times a year is a good practice, especially if you do some unguided images from
time to time. PEMPro also includes a powerful polar alignment routine.
Pier Mounting Options
The 1100GTO mount integrates a precision rotating pier adapter
and azimuth adjuster as part of its base. The mount's base will directly attach
to the Astro-Physics pier, or it can be attached to any flat surface using
the Flat Surface Adapter
for 1100GTO and all 900 Mounts (119FSA). If you plan to use an 8" ATS
pier, you will need the Flat
Surface Adapter with Flat Pier Plate for 1100GTO and all 900 Mounts (119FSA-FP).
The 1100GTO's wide adjustable 0 to 78 degree latitude range (which spans
from Antarctica to the arctic circle) makes the use of a wedge unnecesary.
Dimensions
To determine the appropriate pier height for your system and to calculate many of the dimensions that vary with your latitude setting, please try this Excel spreadsheet Latitude Dimension Calculator.
Support
All Astro-Physics mounts are supported by a dedicated staff who will assist with any issues that may arise. You can talk to a real person in a timely manner. Astro-Physics staff also participate in the ap-ug and ap-gto user groups in the Yahoogroups forum. The user groups are comprised of scope and GTO owners who are willing to share their wealth of experience using their mounts as well as imaging strategies and other concerns of advanced amateurs.
Price and Delivery Information
Prices for mounts with Absolute Encoders reflect $1,000
SAVINGS !!
30% discount on Astro-Physics
Command Center (APCC) when you purchase APCC within 45 days of the date your mount ships.
Shipping charges: $200 for ground shipment within the 48 continguous states; contact us for other destinations.
1100GTO: 1100GTO German Equatorial
Mount
What’s Included:
- Polar Fork / Right Ascension Axis (R.A.) Assembly
- Declination Axis (Dec.) Assembly
- GTOCP4 Servo Control Box
- Control Box Adapter
- 14" Stainless Counterweight Shaft, 1.875" diameter (M9404-A) and Safety
Stop (M12676)
- R.A. and Dec. Y-Cable
- Power Cable Set for GTOCP4, includes 6' Cable with PowerPole Connector, 18" Cable with Cigarette Lighter Plug and 18" Cable with Ring Terminals (CABPP4SET)
- 15' Straight-through Serial Cable (CABSER15)
- Allenhead wrench set
- CD containing: PEMPro v2 Software written by
Ray Gralak of Sirius Imaging. Also, PDF of 1100GTO and GTO Keypad instruction
manuals
- Manual: 1100GTO German Equatorial
- Manual: GTOCP4 Servo Motor Drive System
- Registration Card
1100GTO-AE: 1100GTO German Equatorial Mount with Absolute Encoders (Standard Temperature Range)
What’s Included:
- All items listed above for the 1100GTO
- R.A. and Dec. Absolute Encoders, installed
- R.A. and Dec. Readhead with wire harness, standard temperature version,
installed
- Junction Box and Cables
- CD with Absolute Encoder Utility (Windows-based)
- All required fasteners
- Note: The Astro-Physics
Command Center (APCC) software is not included as part of this package.
It is available as an optional purchase.
- All accessories that are listed as suitable for the 1100GTO are appropriate
for this version of the mount, as well, with the exception of the Limit/Homing
Switch System, which would not be needed anyway.
1100GTO-AEL: 1100GTO German Equatorial
Mount with Absolute Encoders (Extended Temperature
Range)
What’s Included:
- All items listed above for the 1100GTO-AE, except that the Readheads
are the Extended Temperature Version.
- Note: The Astro-Physics
Command Center (APCC) software is not included as part of this package.
It is available as an optional purchase.
- All accessories that are listed as suitable for the 1100GTO are appropriate
for this version of the mount, as well, with the exception of the Limit/Homing
Switch System, which would not be needed anyway.
Items that You will Need for Your Mount
- Counterweight: Stainless
Steel Counterweights - 5, 10, 18 and 30 lb.
- Saddle Plate:
DOVELM162,
DOVEDV10,
900RP,
FP1800,
DOVE15
- D-Style (3") Dovetail Plate: Check out our wide
selection of
D-Style
Dovetail Plates, 13" and
16" Side-by-Side Plates (SBD13SS and SBD16SS) and Vixen
Dovetail Converter (SBD2V)
- Pier: Astro-Physics Portable Pier - 8" diameter, heights 24",32",42",48",54",62", Advanced Telescope Systems (ATS) Portable Pier or build your own permanent pier
- Regulated Power Supply: 13.8-volt, 5-amp (PS138V5A) or 25 Amp Variable Volt Power Supply (PSVPW25A) Regulated Power Supply with Cigarette Adapter
- Portable Rechargeable 12-volt Battery Pack: 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! We recommend
having separate batteries - one for the mount and another for all other accessories:
camera, dew removers, etc. We do not offer any battery packs at this time.
Additional Accessories to Consider
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Copyright © 2018 Astro-Physics,
Inc. - All Rights Reserved
This page was last modified:
July 24, 2018
Astro-Physics, Inc.
11250 Forest Hills Road, Machesney Park, IL 61115, U.S.A.
Phone: 815-282-1513 Fax: 815-282-9847