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Crux T4000 Harmonic Drive Mount - up to 180kg Imaging Capacity

can be shipped within 30-45 days

Price includes VAT, plus delivery

Crux mounts feature Harmonic Drive / Strain Wave Gear Tecnology. This tecnology gives Crux mounts the following advantages over traditional drive systems for astronomy applications;

 - The mounts have zero backlash and therefore pointing and guiding can be very accurate

 - They have very high torque. This makes it ideal your use with all loads. For instance the length of a refractor normally requires a much more powerful mount than a typical weight capacity suggests. The load limits for Crux mounts are for all types of telescopes and also for imaging

 - The motor is very compact and therefore allows a small form factor, resulting in less bulk and weight.

 - Harmonic Drive motors are very responsive and therefore react instantly to guiding commands. When combined with the zero backlash this allows for extremley accurate tracking. There is none of the high frequency oscillation normally associated with traditional drive systems.

 - The high torque of the motor permits use without a counterweight, further reducing the overall weight. If a counterweight is added, the load capacity can be increased significantly. Note that this counterweight is not used to balance the telescope in the normal way. It is simply helping the drive system and making the load safer.

Please see the short video below for an explanation of how the Harmonic Drive system works.




The Crux T4000 is Hobym Observatory's ultimate mount and is observatory class. It has a very high payload capacity of up to 180kg. Combined with its extreme torque capability, the T4000 is compatible with all load types be it a large diameter reflector or large and long specialised refractor. It is a split axis design which helps facilitate installation. Total weight of the mount is still only 54kg (32kg for RA, 22kg for DEC)

An option for the T4000 is to have the RA head extended to better locate certain telescopes with reference to the pier position. For specifications of this and additional costs, please contact us for details.
As with all Crux mounts, the T4000 is provided with a mounting point for a
QHY Polemaster. No adapter is needed. This makes polar alignment using the built in Altitude and Azimuth controls very simple. It is understood however that for a mount of this class, polar alignment will probably be handled via observatory software but the polemaster will allow for very simple initial setup of the mount.
Supplied with all Crux Mounts is the Titan TCS Controller. This provides GoTo functionality and all other mount control and connectivity. It is based on the LX200 protocol and is therefore fully ASCOM and INDI compliant. It also features wireless connectivity in the form of Bluetooth, with WiFi being added shortly. Thus is allows easy integration with Tablet applications such as Sky Safari and of course PC based applications.
One significant function of the Crux mount and TCS Controller is PEC training. This is where, using a guide system (like PHD2), the drive system is trained. This, once completed permanently (unless reset by the user) lowers the PE of the T4000 to typically +/- 3 arc seconds dependent on the mount. This enhanced error can then be combined with guiding leading to extremely low PE. Potentially as low as 0.1 arc sec. As part of our service, we PEC train each mount before delivery so you receive a mount that is capable of operating at its best, straight out of the box. A copy of the PE test data is also provided.

General Specifications - Crux T4000
Type German Equatorial
Azimuth Adjustment Range +/- 15°
Altitude Adjustment Range 20 to 60°
Weight (excl counterweight) 54kg
Optional Counterweights 12kg x 4
Max Load (No Counterweight) 60.0kg
Max Load (with 4 x 12kg) 180.0kg
Power Source 12V DC
Telescope Mounting Format  M10 x 4 / 8x M8 35mm Spacing
Polar Alignment Support Polemaster Mounting
Dimensions 700mm x 536mm x 320mm (at 50° Altitude)
Backlash Zero
PE Error after PEC Training +/- 3 arc sec (after PEC)
High Speed Slewing x400
Titan TCS Controller  
Size 83x87x36mm
Input Power 12-30V DC
Protocol LX200
Database NGC,IC,Messier, Planet 12000+ Object
Power Consumption (Tracking) 12V 0.3-0.5A
Power Consumption (Max Slew) 12V 1.5-2.0A
Wireless Connectivity Bluetooth (WiFi to be added)
Interface RS232 / USB / ST4 Guide


Product Note Status Price
Compact 8cm Losmandy Clamp Compact 8cm Losmandy Clamp
£55.00 *
Compact 16cm Losmandy Clamp Compact 16cm Losmandy Clamp
£85.00 *
Losmandy DVSBS Side by Side Dual Clamp Losmandy DVSBS Side by Side Dual Clamp
£369.00 *
Losmandy G11 SPDV Universal Clamp Losmandy G11 SPDV Universal Clamp
£189.00 *
QHY PoleMaster Polar Alignment Camera QHY PoleMaster Polar Alignment Camera
£229.00 *
Prices includes VAT, plus delivery
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Browse these categories as well: Motorised Mounts, Crux (Hobym Observatory)