ZWO AM5N - Harmonic Mount

Designed to combine payload capacity, precision and portability, the ZWO AM5N is a strain wave gear mount intended for both astrophotography and visual astronomy.

The mount body weighs only 5.5 kg while providing a reference payload of up to 15 kg without a counterweight. For more demanding configurations, this can be increased to 20 kg when a suitable counterweight is used.

Its drive system combines strain wave gearing with a synchronous belt and an overall reduction ratio of 300:1. Periodic error remains below ±10 arc-seconds, and every mount is supplied with its own individual 360° periodic-error test report.

The AM5N operates in both equatorial and alt-azimuth modes. It can therefore be used for astronomical imaging with equatorial tracking or visual observing in an alt-azimuth configuration.

Its 0 to 90° latitude range allows the mount to operate from equatorial to polar regions.

ZWO has also incorporated several features intended to simplify a modern astrophotography setup, including USB, Wi-Fi and Bluetooth connectivity, ST-4 guiding, integrated cable management, a DC power output and a Type-C connection at the saddle.

The mount integrates with the ASIAIR ecosystem and also supports SkyAtlas, ASIStudio, ASCOM and INDI.

Strain Wave Gear Drive

The AM5N drive system combines:

• Strain wave gear
• Synchronous belt
• Overall reduction ratio : 300:1

This technology provides substantial torque from a compact mount while reducing the balancing requirements normally associated with conventional equatorial mounts.

The transmission components use a sealed construction designed to protect the drive system and maintain consistent performance.

Precision and Periodic Error

Periodic error is below:

• ±10 arc-seconds

Periodic-error cycle:

• 288 seconds

Every AM5N is individually tested and supplied with its own 360° periodic-error report.

Drive resolution is:

• 0.17 arc-second

Right-Ascension Drive

The right-ascension axis uses:

• Stepper motor
• Synchronous belt
• Type 17 strain wave gear with 100:1 reduction
• Integrated brake

The RA brake protects the equipment if power is lost.

Declination Drive

The declination axis uses:

• Stepper motor
• Synchronous belt
• Type 17 strain wave gear with 100:1 reduction

Payload Without Counterweight

For a typical setup, the maximum reference payload is:

• 15 kg

No counterweight is required when the geometry and distribution of the equipment remain suitable.

Payload With Counterweight

For a heavier setup or one generating greater torque, the reference payload can reach:

• 20 kg

ZWO recommends using a counterweight in this configuration.

Maximum recommended counterweight:

• 5 kg

With a 5 kg counterweight, the recommended distance from the mount axis is approximately:

• 20 to 30 cm

Payload and Telescope Length

The 15 kg and 20 kg figures are reference values rather than fixed limits independent of setup geometry.

Actual usable payload also depends on:

• Total telescope and accessory weight
• Telescope length
• Centre-of-gravity position
• Distance of the load from the mount axis
• Overall weight distribution

A long optical tube can generate greater mechanical load than a compact telescope of the same weight.

Counterweight and Torque

ZWO recommends that the counterweight generates between:

• 10 and 15 N·m

With a 5 kg counterweight, this corresponds to approximately:

• 20 to 30 cm from the axis

Counterweight-bar thread:

• M12 × 1.75

Equatorial and Alt-Azimuth Modes

The AM5N provides two operating configurations:

• Equatorial mode
• Alt-azimuth mode

Equatorial mode is intended for astronomical tracking and astrophotography.

Alt-azimuth mode also allows the mount to be used for visual observation.

Latitude Adjustment

Latitude range:

• 0 to 90°

This allows operation at all geographic latitudes.

Azimuth Adjustment

Fine azimuth adjustment range:

• ±6°

Losmandy and Vixen Saddle

The saddle supports both common dovetail standards:

• Losmandy
• Vixen

This provides compatibility with a wide range of optical tubes.

Slewing Speeds

Maximum slew speed:

• 6° per second

Available speeds:

• 0.5x
• 1x
• 2x
• 4x
• 8x
• 20x
• 60x
• 720x
• 1440x

The 720x setting is the maximum speed used in heavy-load mode.

Mechanical Zero Position

The AM5N uses a mechanical zero position.

The mount can automatically return to this reference position from another orientation.

RA Power-Off Brake

The right-ascension axis incorporates a brake.

If power is lost, it prevents the axis from moving freely under the weight of the installed equipment.

Integrated Cable Management

The AM5N incorporates cable-management features around the telescope saddle.

Connections include:

• DC power output
• Type-C port

This arrangement reduces cables running between the telescope and the stationary part of the mount and helps prevent cable entanglement during slewing.

USB Connectivity

USB connectivity can be used for:

• Mount control
• Firmware updates

USB cables are supplied for different connection configurations.

Bluetooth Connectivity

Bluetooth provides another method of controlling the mount through the compatible application.

A dedicated button is used to confirm pairing with the correct AM5N and prevent accidental connection to another nearby mount.

Wi-Fi Connectivity

The mount also supports:

• Wi-Fi

This provides an additional wireless-control option.

ASIAIR Compatibility

The AM5N is designed to integrate with:

• ASIAIR

This allows the mount to operate as part of a ZWO astrophotography system.

Software Compatibility

Control is also supported through:

• SkyAtlas
• ASIStudio
• ASCOM
• INDI

The AM5N can therefore be controlled from both mobile devices and computers.

Application Control

Available application functions include:

• GoTo
• Star chart
• Target selection
• Recommended targets
• Mount control
• Firmware upgrades

OTA updates allow the mount and hand controller firmware to be updated from a smartphone.

ST-4 Autoguiding

A dedicated guiding port is provided:

• ST-4

This accepts a compatible autoguiding system.

Low-Temperature Heavy-Load Mode

The AM5N includes a mode intended for low temperatures and heavier payloads.

It can be enabled through the application to adapt mount operation when low temperatures affect mechanical performance.

Operating Temperature

Operating range:

• -20 °C to +40 °C

Power

Recommended supply:

• 12 V DC

Required current:

• Minimum 3 A
• 3 to 5 A recommended at the power input

Connector:

• DC 5.5 × 2.1 mm
• Centre-positive polarity

When voltage falls below:

• 10.8 V

the mount provides an audible low-voltage warning.

Technical Specifications

• Manufacturer : ZWO
• Model : AM5N
• Type : Strain wave gear mount
• Modes : Equatorial and alt-azimuth
• Drive : Strain wave gear and synchronous belt
• Reduction ratio : 300:1
• Periodic error : Below ±10″
• Periodic-error cycle : 288 s
• Resolution : 0.17″
• RA drive : Stepper motor, belt and strain wave gear
• DEC drive : Stepper motor, belt and strain wave gear
• Brake : RA axis
• Reference payload without counterweight : 15 kg
• Reference payload with counterweight : 20 kg
• Recommended counterweight : Maximum 5 kg
• Distance with 5 kg counterweight : Approximately 20 to 30 cm
• Mount weight : 5.5 kg
• Latitude range : 0 to 90°
• Azimuth adjustment : ±6°
• Saddle : Losmandy and Vixen
• Counterweight-bar thread : M12 × 1.75
• Maximum slew speed : 6°/s
• Slew speeds : 0.5x, 1x, 2x, 4x, 8x, 20x, 60x, 720x and 1440x
• Autoguiding : ST-4
• Communication : USB, Wi-Fi and Bluetooth
• Compatibility : ASIAIR, SkyAtlas, ASIStudio, ASCOM and INDI
• Zero position : Mechanical
• Cable management : Yes
• Saddle DC output : Yes
• Saddle Type-C port : Yes
• Operating temperature : -20 °C to +40 °C
• Power : 12 V DC
• Current : Minimum 3 A
• Connector : 5.5 × 2.1 mm
• Polarity : Centre positive
• Low-voltage warning : Below 10.8 V

Package Contents

• ZWO AM5N mount
• Foam protective case
• Hand controller
• 2 m hand-controller connection cable
• 2 m USB 2.0 Type-B to Type-A cable
• 1 m USB 2.0 Type-C to Type-A cable
• Individual AM5N periodic-error test report
• Quick guide
• M6 hex key