Astro-Physics GTO-Mach 1 Mount

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Astro-Physics GTO-Mach 1 Mount

# 1401371

€ 7,200.00 Price excl. German VAT tax (19%): € 6,050.42

  • German Equatorial Mount with Servo Motor Drive
  • Precision-Adjust Rotating Pier Base / Hi-Res Azimuth Adjuster
  • built-in adapter for the Right-Angle Polar Alignment scope
  • rear-mounted Azimuth Adjuster and larger cable openings
  • the R.A. and Dec. axes split easily into two pieces to fit into a more compact case
  • with GTOCP4 Control Box and Auto-Adjusting Motor/Gearboxes, optional GTO Keypad available
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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Astro Physics MACH1 S&T Hot product

Astro-Physics Mach1GTO German Equatorial Mount

with GTOCP4 Control Box and Auto-Adjusting Motor Gearbox

The GTO-Mach1 of Astro-Physics succeeds the CNC 400 and also the GTO 600E.

The GTO-Mach1 was presented in 2006 and was promptly chosen as one of Sky & Telescope's Hot Products for 2007! There is much to admire in the Mach1GTO. It is beautifully machined, intelligently designed, precisely fabricated and assembled, and it has sophisticated electronics and servo drive controls. At the moment, the MACH 1 is the only mount of German design in its class, in which ALL cable connections to the telescope (CCD camera, electric focusing, etc.) are passed through the polar axis. Both axes have 2 inch clearance holes down the center with no shafts protruding into the holes. Wires from CCD cameras and accessories can be inserted from the bottom of the RA axis to emerge from the top of the Dec axis. Channels have been machined to allow the cables to be routed under the mounting plates. There is no restriction of rotation with the wires inserted - one can rotate both axes more than 360 degrees without catching the wires on any parts.

Astro Physics Mach1 GTO

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 Astro-Physics and individually tested to meet or exceed Astro-Physics 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.

The GTO-Mach1 at a glance:


But the most important feature first...

Astro-Physics has designed new motor/gearboxes for all Astro-Physics mounts - also for the GTO-MACH1. The 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
  • 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 and GTOCP4 Control Box. See video above.

Some more highlights...

  • completely redesigned CTOCP4 Control Box with modern chip technology resulting in faster processing speed and increased memory capacity for future feature additions. More information about the GTOCP4 Controll Box are available here.
  • portable enough for airline travel - the entire mount will fit into a single rugged case. If needed, the R.A. and Dec. axes split easily into two pieces to fit into a more compact case.
  • fast and precise Polar Alignment - our clever CNC machined Right Angle Polar Alignment Scope (RAPAS) allows you to polar align the GTO-Mach1 in record time and with a precision that permits you to quickly begin imaging.
  • built-in adapter for the Right-Angle Polar Alignment scope and larger cable openings
  • the azimuth adjuster knobs are now at the rear of the R.A. axis, which provides easier access and nearly doubles the precision of their adjustments. An etched line on the adjuster housing corresponds with the ridges of the knobs to provide a measured adjustment of 0.7021 degrees (42 arcminutes) per rotation or 0.05 degrees (3 arcminutes) per ridge.
  • 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
  • it has been machined out of solid aluminum to withstand the high axial and thrust loads that a medium-sized telescope places on the mount under real-world observing conditions. Using modern CNC machining techniques, all components are made 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.
  • operate with 12V battery or regulated Power Supply
  • 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)
CP4 Control

Detailed information about the GTOCP4 are available here.

For detailed information about the Mach1GTO 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.

Dennis di Cicco had this to say about the Mach1GTO's performance:

The mount's tracking and Go To pointing are among the most accurate I've ever tested. At the end of each night I'd park the scope and turn off the power. Whether an hour, day, or week elapsed until I'd power up the mount again and "resume from park," it would have perfect sync with the sky - even to the point of "hiding" stars behind my finderscope's crosshairs when I'd check the alignment by slewing to them in a bright twilight sky . . . Such Go To pointing precision comes in handy when shooting photographic mosaics, making a sequence of deep exposures of the same field on multiple nights, or hunting difficult targets by eye.

GoTo in perfection

The Mach1GTO is compatible with PulseGuide and PemPro. With PulseGide and PEMPro, you can achieve even higher levels of accuracy.

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 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 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

For detailed information about the Mach1GTO 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.

What's included:

  • Mach1GTO Equatorial Head (R.A. & Dec. Assembly) with Servo Drive Motors (includes built-in adapter for Right-Angle Polar Alignment Scope)
  • GTO Servo Control Box (GTOCP4)
  • Control Box Adapter (CBAPT)
  • 13.675" Stainless Steel Counterweight Shaft, 1.125" diameter with Machined Safety Stop Knob
  • Y-Cable for R.A. and Dec.
  • 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
  • 1/4-20 Machined Knob Kit
  • Allenhead wrench set
  • CD containing: PulseGuide Software by Ray Gralak of Sirius Imaging and PDF of Mach1GTO and Keypad instruction manuals
  • Registration Card
  • ASCOM driver, available by download

Accessories for older GTO-Mach 1 mounts can be found in our Astro-Physics price list.

    • Precision-Adjust Rotating Pier Base for Mach1 GTO #1401081

      Regardless of the mount's load, hi-res adjustments can be made in azimuth with no lockdown needed, which could shift your position.

    • Upgrade 1/4-20 Machined Knob Kit, set of 3 #1401097

      These "way-cool" knobs with sure-grip profile and elegantly tapered shank are CNC machined of aluminum, black-anodized and assembled with a 1/4-20 stainless socket head cap screw. They were designed to replace the plastic knobs used in the past for our Mach1GTO, 400, 600 and 600E mounts as well as past and current accessories

These features were introduced in June 2011. If you own a mount shipped in prior years, the base can be easily removed and upgraded with these features.

Note: All Mach1GTO mounts shipped beginning in 2014 (serial number M10670 and later) will have the adapter for the Right-Angle Polar Alignment Scope built in. Mounts shipped in prior years must purchase the Right-Angle Polar Alignment Scope Adapter for Mach1GTO separately. Further information about Mach1GTO Updrades can be found on the original website of Astro-Physis

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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Additional Information

Manufacturer Astro Physics
Manufacturer SKU (#) Mach1GTO
SKU (#) 1401371
EAN Code 4047825017857
Weight (kg) 17.4
Mount German Equatorial mount (motorized)
Control system electronics GTOCP4 Control Box
Software ASCOM V2 Driver, PulseGuide by Ray Gralak, Sirius Imaging
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
Motor Zero-cogging Swiss DC servo motors, enclosed in machined aluminum housing
Payload Capacity (kg) approximately 65 lb. (30 kg) of scope and accessories, depending on length. Recommended for: Astro-Physics and similar fast refractors up to our 160 mm f7.5 Starfire EDF, 8-12" SCTs and 8-10" Maks.
Power Requirements Nominal 12 volt DC supply at minimum of 5 amps continuous
Power consumption ~ 0.3 to 0.5 amps at 13.8 volts - tracking, ~ 1.0 to 2.2 amps at 13.8 volts - both motors slewing at 1200x
Axis Shaft - RA & DEC 2.36" (60 mm) diameter
Mount Weight Total: 32.1 lb. (14.6 kg), R.A. axis/polar fork: 16.5 lb. (7.5 kg), Dec. axis: 11.5 lb. (5.2 kg), Counterweight shaft: 4.1 lb. (1.9 kg)
Weight of Counterweights 4.1 lb. (1.9 kg)
Counterweight Shaft 1.125" (29 mm) diameter x 13.625" (346.1 mm) useable length, incl. washer and safety knob. Optional counterweight shaft (M1053-A) available: 1.875" (48 mm) diameter x 9.675" (246 mm) useable length; fits inside Dec. axis for transport. Requires Safety Sto
Worm Wheel RA & DEC 5.9" (150 mm), 225 tooth aluminum
Worm Gear RA & DEC 0.705" (17.9 mm) diameter, special low-wear alloy
Latitude Range 0 to 70 degrees
Slew Speeds 5 degrees / second
Azimuth adjustment Approximately 13 degrees (+/- 6.5 degrees from center)
Tracking Performance and Periodic Error < 7 arc seconds peak-to-peak (+/- 3.5 arc seconds)
Shaft axis bearing- R.A. & DEC 3.1" (78 mm) diameter, 2 per axis

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