Astro-Physics 1150GTO
Precision tracking. Serious payload capacity. Built for automated imaging, remote observatories, and demanding astrophotography.
Observatory Performance Without Giving Up Portability
The Astro-Physics 1150GTO is a mid-sized observatory-class German equatorial mount designed for large astrophotography systems, automated observatories, and demanding field installations.
With approximately 125 lb (57 kg) of instrument capacity, the 1150GTO provides the rigidity and tracking performance required for substantial imaging systems while retaining separable RA and Declination assemblies for easier transport and installation.
Built Around the Needs of Serious Imaging Systems
Large Imaging Systems
Approximately 125 lb of instrument capacity makes the 1150GTO suitable for substantial refractors, Cassegrains, Ritchey-Chrétiens, CDKs, cameras, guiders, focusers, and imaging accessories.
Through-the-Mount Cabling
Integrated pathways for power, USB, and Ethernet help simplify complex observatory and imaging installations while reducing external cable movement around the mount.
Separable Axes
The RA and Declination assemblies can be separated, reducing the weight of the individual components during transport, setup, or observatory installation.
1150GTO Features
- Approximately 125 lb (57 kg) instrument capacity
- Integrated power, USB, and Ethernet cabling
- Quiet, powerful belt-drive system
- Brushless micro-stepper motors
- Self-synchronizing Periodic Error Management
- Auto-adjusting gear mesh
- Precision balancing through the clutches
- Flexible 12–24V DC operation
- Precision azimuth adjuster with rotating base
- Built-in bubble level
- Defined park positions for simplified daytime alignment
- Custom tracking rates in both axes
- ASCOM V2 driver support
- Optional Astro-Physics GTO Keypad compatibility
- Threaded for QHY PoleMaster installation
- RA and Declination axes separate for transport
Choose the 1150GTO Configuration
1150GTO
The standard 1150GTO configuration delivers Astro-Physics precision mechanics and GTOCP6 control without factory-installed absolute encoders.
1150GTO-AE
Adds factory-installed dual Renishaw absolute encoders designed for the standard operating-temperature range.
1150GTO-AEL
Includes factory-installed dual absolute encoders with the extended-temperature encoder configuration.
Sky-Aware Absolute Encoder Performance
Astro-Physics specifies periodic tracking error of approximately 0.19 arcsecond peak-to-peak and 0.05 arcsecond RMS for the absolute-encoder-equipped AE and AEL versions.
The absolute encoder system also gives the mount "Sky-Aware" axes. The clutches can be loosened and the telescope repositioned manually while the mount retains knowledge of its pointing position.
The rapid encoder feedback loop also helps the axes resist outside disturbances such as cable drag and wind loading.
GTOCP6 Control System
The included GTOCP6 control box provides the electronic interface between the precision mechanics of the 1150GTO and modern observatory or astrophotography software.
Flexible Connections
Physical connectivity includes USB, Ethernet, Wi-Fi, and RS-232, allowing the mount to fit into a wide variety of portable and permanent imaging configurations.
ASCOM Support
Astro-Physics' ASCOM driver provides integration with compatible ASCOM astronomy software for imaging, pointing, sequencing, and observatory control.
GTO Keypad
The optional Astro-Physics GTO Keypad provides independent mount operation for observers who prefer a dedicated hand controller rather than a computer in the field.
APCC Pro & PEMPro Included
An Astro-Physics Command Center Pro (APCC Pro) software license is included with the 1150GTO, along with PEMPro v3.
APCC Pro adds advanced mount-control and modeling capabilities, including pointing and tracking-rate corrections. Astro-Physics' dual-model capability can also provide pointing and tracking correction when the telescope is in the counterweight-up position.
Individually Optimized Tracking
Each mount is tested by Astro-Physics for periodic-error performance. The standard 1150GTO is specified at ±3.5 arcseconds of native periodic error before correction.
Astro-Physics generates a unique optimized periodic-error curve for each mount and programs it into the GTOCP6 control system. Periodic Error Management can then be enabled through Astro-Physics software or the optional GTO Keypad.
1150GTO Specifications
| Instrument Capacity | Approximately 125 lb (57 kg) of telescope and accessories, depending on instrument size and length |
| Recommended Telescope Range | Refractors up to approximately 200 mm; 14–16" Cassegrains, Ritchey-Chrétiens, and CDKs, subject to instrument dimensions and imaging requirements |
| RA Axis / Polar Fork | 31.7 lb (14.4 kg) |
| Declination Axis | 21 lb (9.5 kg) |
| Latitude Range | 0° to 78° |
| Azimuth Adjustment | Approximately 18° total, ±9° from center |
| Counterweight Shaft | 1.875" (47.6 mm) diameter × approximately 16.4" (419 mm) usable length |
| Counterweight Shaft Weight | 13 lb (5.9 kg) |
| RA & Dec Worm Wheels | 7.2" (183 mm), 225-tooth aluminum |
| RA & Dec Worm Gear | 0.71" (18 mm) diameter |
| RA & Dec Axis Shaft | 3.15" (80 mm) diameter |
| Axis Bearings | 3.94" (100 mm) diameter |
| Native Periodic Error | ±3.5 arcseconds before correction |
| AE / AEL Periodic Error | 0.19 arcsecond peak-to-peak; 0.05 arcsecond RMS |
| Pier Adapter Base Diameter | 7.730" (196.3 mm) |
| Power | 12–24V DC |
| Control Box | Removable GTOCP6 |
| Motors | Brushless micro-stepper motors enclosed in machined aluminum housings |
| Origin | Designed and manufactured in the USA |
What's Included
1150GTO Mount System
- 1150GTO equatorial head
- GTOCP6 Servo Control Box
- GTOCP6 control box adapter
- Stainless-steel counterweight shaft
- Machined counterweight shaft safety-stop knob
- Power cable set with Anderson Powerpole connectors
- Allen-head wrench set
- Astro-Physics ASCOM driver download
- APCC Pro software license
- PEMPro v3 software
- 1150GTO and GTOCP6 documentation
Equipment You'll Need
- Compatible 12–24V DC power supply
- Appropriate counterweights
- Compatible telescope mounting plate or saddle
- Suitable pier or tripod
- Any application-specific internal USB or power cabling
Important: A power supply, counterweights, telescope mounting plate/saddle, and pier or tripod are not included unless specifically identified as part of a Starizona package or selected product option.
Frequently Asked Questions
How much weight can the 1150GTO carry?
Astro-Physics rates the 1150GTO for approximately 125 lb (57 kg) of telescope and accessories. Actual suitability also depends on the telescope's length, physical dimensions, moment arm, and whether the system will be used for visual observing or precision imaging.
What is the difference between the 1150GTO, AE, and AEL?
The 1150GTO is the standard model. The 1150GTO-AE adds factory-installed standard-temperature absolute encoders on both axes. The 1150GTO-AEL uses the extended-temperature absolute encoder configuration.
Does the 1150GTO include APCC Pro?
Yes. Astro-Physics includes an APCC Pro software license with the 1150GTO. PEMPro v3 is also included.
Is a power supply included?
No. Astro-Physics specifies a compatible 12–24V DC power source, but the power supply itself must be purchased separately.
Can the mount be separated for transportation?
Yes. The RA and Declination axes can be separated. The RA axis and polar fork weigh approximately 31.7 lb, while the Declination axis weighs approximately 21 lb.
Can the AE/AEL mount be moved manually without losing position?
Yes. Astro-Physics describes the absolute-encoder-equipped versions as having "Sky-Aware" axes. The clutches can be loosened and the telescope repositioned while the mount retains its pointing position.