Astro-Physics GTO-1600 Mount (various versions available)

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Astro-Physics GTO-1600 Mount (various versions available)

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€ 19,200.00 Price excl. German VAT tax (19%): € 16,134.45

  • German Equatorial Mount with Servo Motor Drive, replaces GTO 1200
  • the R.A. and Dec. axes split easily for a more comfortable assembly and / or transport - with 220 lb. (100 kg) instrument capacity
  • with GTOCP4 Control Box and Auto-Adjusting Motor/Gearboxes
  • optional with Encoders in R.A. und Dec Axis available - various versions at the dropdown below
Important note: This product is not available online. If you are interested, please send us a formal inquiry incl. contact data by email. We shall gladly provide a detailed offer.

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€ 19,200.00 Price excl. German VAT tax (19%): € 16,134.45

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Astro-Physics GTO-1600 German Equatorial Mount

Astro Physics 1600GTO S&T Hot product

with GTOCP4 Control Box and Auto-Adjusting Motor/Gearboxes - optionally available with or without absolute encoder

The GTO-1600 succeeds the legendary 1200GTO of Astro-Physics

Thirty plus years of mount design and building expertise of Astro-Physics has been employed to engineer and manufacture the GTO-1600 mount into a robust, high-precision mount. Astro-Physics has enhanced its design and utility by incorporating additional optional features like absolute encoders, sophisticated control systems and a precision polar scope to meet the needs of even the most demanding astro-imager or visual enthusiast.

The GTO-1600 mounts are especially remarkable, because they are fully transportable - despite their high instrument load. This is possible because the declination axis can be separated from the rest of the mount. The connection of the two components is achieved by a CNC-machined dovetail receptor clamp. The R.A. axis/polar fork weighs 63.7lb (28.9 kg) and the DEC axis 40lbs (18.1 kg). The GTO-1600, with 220 lb. instrument load, can be transported and set up by one person!

Improved Features compared to the 1200GTO, its predecessor:

But the most important feature first...


Astro-Physics has designed new motor/gearboxes for all Astro-Physics mounts - also for the GTO-1600. The 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
  • Worms made with high-strength alloy eliminates wear during long periods of slewing, especially useful for remote setups that do survey work
  • 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.

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. Dennis DiCicco, editor of Sky & Telescope magazine, opens the interview with a discussion of the 17" f8 Flat Field Astrograph. See video.

Some more highlights ...

Polsucher 90 Grad.jpg
Astro Physics GTO 1600
  • larger motors for increased torque in cold temparatures
  • completely redesigned with modern chip technology resulting in faster processing speed and increased memory capacity for future feature additions. More information about the GTOCP4 Controll Box is available here.
  • Dec. axis gear increased to 10.3" 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
  • major altitude adjustments are extremely easy to make. Simply shift the position of the bar into a new slot without having to line up obscure holes referenced in the manual. The large "captain's wheel" knob is also very easy to grasp and turn. If you travel to a star party at a different latitude, you can make changes to your setup very quickly. This also allows you to transport the RA assembly in a more compact, zero degree latitude configuration.
  • built-in precision-rotating pier adapter
  • Altitude range now extends from 0-78 degrees, which makes it suitable for most anywhere except the extreme polar locations.
  • 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.
  • 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.
  • greater capacity of 220lb.
  • Control box mounted vertically rather than on the top to reduce the possibility of moisture getting into the electronics in damp environments
  • Right-angle connectors are used where applicable to reduce strain on the cables
  • easy to adjust and maintain. All components are modular
  • 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.
  • You can align the GTO-1600 using setup routines in the optional keypad, or with a polar alignment scope to quickly zero in on the pole for most non-critical observing or to get close before tweaking in for imaging (polar scope not included). 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.
  • operate with 12V battery
  • Clutches allow manual operation if power is not available
  • Absolute Encoder option to provide error-free tracking, software readable absolute position, customizable home and limit functions for robitic imaging
CP4 Control

For detailed information please visit the original website of Astro-Physics

Astro-Physics specifies an instrument load of approximately 220 lb. (100 kg), depending on length. Recommended for refractors up to 250 mm, 18-20" 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.

Waht Astro-Physics customers say about the GTO-1600

"As you know I am a huge fan of AP products and think that they are the ultimate in quality and customer support. Having used two of the AP1200 GTO mounts for many years now at two of the observatories, with never so much as a glitch in complete robotic/remote use, they have been completely dependable and trouble-free. Never a glitch, not one. I expected the same out of the 1600GTO and my personal use observatory made room for this mount with great anticipation. Never in my wildest dreams did I expect such absolute perfect performance and quality right out of the box . . . This mount is absolutely the finest piece of equipment that I have ever used; the through-the-mount cabling makes remote use trouble free and worry-free without exception. I am carrying a load of about 120 pounds on the mount (a Meade 16" f/8 ACF, with piggybacked 110mm APO, both equipped with heavy ST2000XM cameras for photometric research) and the mount never complains. In just this first week, after moonset, I have been able to easily get down to below magnitude 20.5 in unguided 120 second exposures with NO PEC applied.....just the excellent and steady tracking of the 1600GTO at work. This is adding tremendous horizons for our NEO research and leading way to extending the ASO exo-planet searches. The precision of this mount and the quality that has obviously gone into building it is extraordinary, truly. In my 47 years of running observatories I have had much larger, and more expensive, mounts....but never in my days have I seen anything to compare to this AP1600GTO. Without exception, it is the finest piece of astronomical equipment I have ever put into use." Dr. C.S., AR

Region M65/M66 withount Guiding Control

GTO-1600 with Absoute Encoders available:

Absolute Encoders allow the mount to know its exact location regardless of accidental software errors and will allow it's recovery. This is particularly important in remote setups. Furthermore, they virtually eliminate periodic error, reducing it below 0.2 arcseconds in our tests.

Astro-Physics recommend that that encoders be installed at the time that you purchase your mount, however you can install them yourself later as your needs change.

Check out the 10 minute (600 seconds) unguided exposure by clicking on the thumbnail to the left.

GoTo in perfection


The 1600GTO is compatible with PulseGuide and PemPro. With PulseGide and PEMPro, you can achieve even higher levels of accuracy.

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. More information about the GTO Keypad is available here.
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 5 arc seconds peak-to-peak (+/- 2.5 arc seconds) or less in one worm cycle (6.4 minutes); native, prior to any error correction
Maximum slew speed 5 degrees / second

What's included (standard version):

  • Polar Fork / Right Ascension Axis (R.A.) Assembly
  • Declination Axis (Dec.) Assembly
  • GTO Servo Control Box (GTOCP4)
  • 23" Stainless Counterweight Shaft, 1.875" diameter and Safety Stop
  • R.A. / 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
  • 15' Straight-through Serial Cable
  • Allenhead wrench set
  • CD containing: PEMPro v2 Software and PulseGuide Software, both written by Ray Gralak of Sirius Imaging. Also, PDF of 1600GTO and GTO Keypad instruction manuals
  • Manual: 1600GTO German Equatorial and GTOCP4 Servo Motor Drive System
  • Registration Card

For detailed information about the GTO-1600 mount please visit the original website of Astro Physics. If you have any further questions, please send us an email to kontakt (at) or call us.


Applies to all mounts which are controlled through plug connections of hand controllers and / or through plug connections with electronic accessories.

Again and again, we receive mounts for repair work, which have malfunctions due to corroded connections. Therefore, the following note:

The plug-in connections at all contact points in astronomical telescopes are generally exposed to humidity and dirt. For the current transmission on such plug-in connections there is often a higher risk of damage due to humidity or corrosion as is ussually the with plug-in connections in the household.

It is advisable to spray the connectors of all cable connections generously with contact spray and then plug in the respective plug several times. In this way, the contact is cleaned and at the same time corrosion and the accumulation of condensation water are prevented. Please do not spray into the socket! In this way, short circuits can be produced if contact liquid is used too generously and runs through electronic components inside the device.

In any case, if there are undefined malfunctions during the electricity or signal transmission, it is first of all advisable to clean the plug-in connections by means of contact spray.

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