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##SOLD## - 1100GTO-AEL: 1100GTO German Equatorial with R.A./Dec. Extended Temperature Absolute Encoders with CP4 Control Box and APCC Pro Software

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Why an 1100GTO?

The 1100GTO is a mid-sized observatory-class mount that will provide reliable operation in your distant, remote observatory *** or *** eagerly travel to star parties where your 12V battery will keep it running all night.

This web page specifically discusses the 1100GTO, though many features are common to all three mount versions.

Features to Enhance your Observing or Imaging Sessions


Extremely solid, rugged, high payload mount, yet the equatorial head comes apart easily into two components for hassle-free field setup. The heaviest component is about 27 lbs (12.5kg).

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 the 25 Amp Variable Volt Power Supply from Powerwerx,  This variable supply can be boosted to 15V if you observe in cold climates or are at the upper end of the capacity recommendations.

Azimuth and Altitude Adjustments are convenient and quick

  • Major altitude adjustments are extremely 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.
  • Azimuth adjusters are located at the rear of mount which allows you to make minor corrections quite easily. Since the knobs are 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 for smooth azimuth adjustments.

Through-the-mount cabling

The RA and Dec motor cables are routed internally to reduce the possibility of snagging. Additional cables can pass 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.


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. Manual operation is possible if power is not available.

Image past the meridian

The mount will track and guide well past the meridian in either direction if the object is located so 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 for many years.

Easy polar alignment for critical viewing

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 optional GTO Keypa, 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).

Auto-Adjusting Motor/Gearboxes

Our motor/gearboxes were designed to be responsive for precision astro-photography, while at the same time making it super easy to use and adjust.

  • Spring-loaded worms maintain full contact under all guiding and slewing conditions
  • Automatic setting for worm mesh requires no adjustments over long time periods
  • Precision balance mechanism allows full backing off the worm from the worm wheel
  • Very low backlash gear train eliminates Dec reversal delays and provides high position accuracy during guiding


Absolute Encoder Option

Absolute Encoders on both axes provide error-free tracking, software readable absolute position, customizable home and limit functions for robotic imaging. This option can be installed when you purchase    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.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.