1100GTO-AE or -AEL
The 1100GTO German Equatorial Mount with the GTOCP3 Control Box is no longer available to purchase. Please refer to information regarding the newest version of the 1100GTO featuring our GTOCP4 Control Box.
The information below is provided for present owners and those who are curious about its history.
Why an 1100GTO?
If the 1600GTO German Equatorial has all the features you desire, but is a bit larger than you need, the 1100GTO was developed just for you. 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:
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 15-volt, 12-amp power supply (PS15V12AC).
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.
|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.|
|. . . 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.|
|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 brass|
|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 14" (356 mm) long [12.875" (327 mm) usable length], incl. large machined safety stop knob. Optional 9" (229 mm) shaft extension available.|
|Weight of mount||
Total: 54.0 lb. (24.5 kg)
|Capacity||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-Chretiens
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. Maximum capacity may require the use of the 9" extension (M12675)
|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.|
GTOCP3 Servo Drive System
The 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
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 GTOCP3 Control Box.
GTOCP3 Control Box
The GTOCP3 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 GTOCP3 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. Extensive information regarding the GTOCP3 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 for casual observation.
GTO 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||GTOCP3 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|
7 arc seconds peak-to-peak (+/- 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
The 1100GTO mount has been designed
and engineered to accomodate the use of extremely precise Absolute
Encoders. These are the exact same encoders as are used on the 1600GTO.
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. This do-it-yourself upgrade option will not be available until 2014.
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!
As this chart shows, there are many options available for controlling your mount. Take a few minutes to link to descriptions of the varied software and devices that are available.
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.
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.
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
The 1100GTO is no longer available with the GTOCP3. Please refer to information regarding the current version of the 1100GTO.
1100GTO: 1100GTO German Equatorial
1100GTO-AE: 1100GTO German Equatorial Mount with Absolute Encoders
1100GTO-AEL: 1100GTO German Equatorial
Mount with Absolute Encoders (Extended Temperature
Items that You will Need for Your Mount
Additional Accessories to Consider
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Inc. - All Rights Reserved
This page was last modified: February 17, 2016
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