What is a Harmonic Drive Mount?
A harmonic drive mount uses a strain-wave gear—a clever mechanism where a flexible metal cup deforms as it rotates inside a rigid housing. That deformation creates an extremely high gear reduction with near-zero backlash and very high stiffness, two traits that matter enormously for astrophotography. Unlike traditional worm gears, a harmonic system has no meshing teeth that rely on perfect alignment, so tracking remains smooth even under changing loads or small temperature shifts.
In practical terms, a well-designed harmonic drive mount delivers high torque in a compact package, fast slews, and remarkably stable guiding when paired with short exposure times. The Prometheus Astro Týr mount uses precision harmonic drives, in combination with gear and belt reduction—750:1 reduction in Right Ascension and 400:1 in Declination—to achieve sub-arcsecond tracking performance under realistic sky conditions. This combination of stiffness, high reduction ratio, and negligible backlash makes harmonic drive mounts particularly well suited for modern portable imaging setups.
Precision Forged in Myth. Built for the Stars.
Named after the Norse god of law, justice, and unwavering resolve, the Týr Harmonic Drive Telescope Mount delivers unmatched accuracy in celestial tracking — a harmonic drive telescope mount engineered for serious astrophotographers and observatories who demand absolute precision.
Týr is not the god of chaos. He is the god of control.
And in the same spirit, the Týr Harmonic Drive Telescope Mount locks onto the heavens with unshakable intent — guiding your optics with sub-arcsecond accuracy, even across long exposures and complex sky paths.
Engineering Highlights
- Geared for unparalleled Precision: With a gearing reduction of 750:1 on the RA and 400:1 on the DEC axis, this mount offers unparalleled guide precision and payload abilities.
- Zero-Backlash Harmonic Drive: Delivers ultra-smooth motion with microscopic repeatability — perfect for deep-sky imaging, planetary stacking, and long-duration tracking.
- Auto Homing: Integrated homing sensors ensure that your mount always knows its way home.
- Through-axis power & USB on dovetail: Týr delivers power and USB connectivity routed directly through the dovetail, ensuring clean, integrated cable management and minimal external wiring.
- Zero-Shift Polar alignment: You can still perform fine-adjustments of Altitude knob on the polar wedge, with the locking bolts tightened. You will no longer experience jumps in alignment when doing final adjustments during polar alignment.
- Compact, Rigid Design: CNC-machined from aerospace-grade 7075 aluminum for maximum stability and minimal vibration.
- Autoguider & ASCOM/INDI-Compatible: Seamlessly integrates with your existing astrophotography workflow. You can use PHD2, N.I.N.A., APT, KStars-Ekos or any other ASCOM or INDI software.
- Maintenance-Free: Run your sessions in total confidence, no drift.
Why Týr?
In Norse myth, Týr sacrificed his hand to tame the beast — not with brute force, but with courage and clarity of purpose.
We chose his name because this mount does the same:
It doesn’t drift. It doesn’t doubt. It simply holds.
It tames the night sky with calm precision.
Ideal For
- Advanced amateur astronomers
- Research observatories and remote setups
- High-resolution planetary and DSO imaging
- Robotic telescope arrays
Technical Specs
- Reduction Ratios: Right Ascention 750:1, Declination 400:1
- Tracking Accuracy: ±0.40 arcsec RMS (can go as low as 0.16 arcsec, depending on seeing, equipment balancing, tripod selection, ground stability and weather)
- Payload Capacity: 20kg / 33lbs without counterweight, up to 42kg / 92.6lbs with counterweights (real world tested at 25kg without counterweights)
- Mount Weight: 4.98 kg
- Backlash: < 10arcsec
- Power consumption: 12V DC / 3A
- Interfaces: USB-B, WiFi (station and access point modes), DC Barrel Jack 2.1mm
- Outputs: 4 x 2.1mm 12V up to 7.5A (fuse protection at 10A)
- Tripod Interface: M10 (for EQ5/EQ6 tripods), iOptrom CEM26/CEM28
- Easily replaceable dovetail (standard 4 screw format) without losing Through-Axis Power functionality
Technical Comparison
| Feature | Prometheus Astro Týr | Other well-known Brand |
|---|---|---|
| Drive & Ratios | RA 750:1 / DEC 400:1 (precision-oriented gearing) Gear & Belt combination (zero-backlash) | RA 400:1 / DEC 300:1 (precision-oriented gearing) Planetary Gearbox (~10-15 arcsecs backlash) |
| Native Periodic Error (PE) | <20 arcsecs | <50 arcsecs |
| Payload (no counterweight) | 20kg | 15kg |
| Payload (with counterweight) | 45kg | 20kg |
| Mount Head Weight | 4,9kg | 5,5kg |
| Homing Sensors | Standard mechanical sensors on RA and Dec | No sensors |
| Through-Axis Power | 4 x 12V 2.1mm output/ up to 7.5A supply standard | None |
| USB at Saddle/Dovetail | USB-B interface on Dovetail | None |
| Control Firmware | OnstepX with Prometheus Astro customization | Deep-native integration, closed code and ecosystem |
| Software Ecosystem | ASCOM/INDI friendly; vendor docs & EU support | ASCOM/INDI friendly, Chinese support |
Crafted with Purpose. Guided by the Gods.
Týr isn’t just a name. It’s a promise — of perfect alignment, of total control, of strength without noise.
If your work reaches for the stars, you need a mount that never flinches.
Aluminum 7075-T6 vs 6061-T6 — Strength Forged for Precision
While most telescope mounts are machined from 6061 aluminum, Prometheus Astro uses 7075-T6, an aircraft-grade alloy chosen for its exceptional mechanical strength, rigidity, and vibration resistance — key to achieving sub-arcsecond tracking precision.
| Property | 7075-T6 Aluminum (Prometheus Astro) | 6061-T6 Aluminum (Typical Competitors) |
|---|---|---|
| Tensile Strength | ≈ 570 MPa | ≈ 310 MPa |
| Yield Strength | ≈ 500 MPa | ≈ 275 MPa |
| Hardness (Brinell) | 150 HB | 95 HB |
| Elastic Modulus | 71 GPa | 69 GPa |
| Density | 2.81 g/cm³ | 2.70 g/cm³ |
| Relative Rigidity / Stiffness | ~1.3× stiffer | Baseline |
| Cost | Higher | Lower |
What This Means for Astrophotographers
What This Means for Astrophotographers
Because every micron matters.
By machining each TÝR mount housing and axis component from 7075-T6 billet aluminum, we ensure maximum structural integrity, minimal flexure, and a distinctly solid feel that you’ll notice every time you guide on a star.
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