Harmonic & Strain Wave Mounts

How Strain Wave Mounts Differ from Worm Gears

• No counterweight needed for many payloads: Strain wave gears are not back-drivable in the same way as worm gears, so moderate payloads can be carried unbalanced. A counterweight still improves stability with heavy or long tubes.
• Periodic error: Strain wave gears have larger and faster periodic error than a good worm gear. Autoguiding is strongly recommended for imaging, and models with high-resolution encoders reduce this.
• No backlash: Direction changes are immediate, which makes guiding and dithering clean.
• Equatorial, alt-az or both: HAE models switch between equatorial and alt-az. HAZ models are alt-az only, built for visual and planetary work. Wave mounts also work in both modes.

Choosing a Size

Payload ratings are maximums. For imaging, plan around 60 to 70% of the rated capacity, and less for long focal lengths or windy sites. A 2.5 kg refractor with camera and guide scope sits easily on an AM3N or HEM27. A 10-inch Newtonian or 11-inch SCT belongs on an AM7, HAE43 or larger.

What We Check Before You Order

• Payload and moment arm: We look at both weight and length. A long tube is harder on the mount than a compact one of the same weight.
• Tripod or pier: A strain wave mount is only as steady as its legs. We recommend a matching tripod or pier extension for meridian clearance.
• Control: We confirm compatibility with ASIAIR, NINA, KStars or your mount's own app.
• Power and cables: We plan power and cable routing so nothing snags during slews.

Harmonic Mounts: Frequently Asked Questions

Do strain wave mounts need guiding?

For long-exposure imaging, yes in most cases. Exceptions are short focal lengths with short exposures, or encoder models with low residual error.

Can I use a harmonic mount for visual observing?

Yes, especially HAZ and HAE models in alt-az mode. They are quick to set up and carry large visual tubes.

What happens if the power fails?

Strain wave gears resist being back-driven, and some models add a power-off brake. Even so, an unbalanced heavy payload can drift, so check the specific model and keep a counterweight on large tubes.

Considering a harmonic mount?

Send us your telescope, camera and guiding plan. We will size the mount with real imaging margin.