Professional electronic focusing, tilt correction and back-focus control in one exceptionally slim, high-payload unit.

The WandererAstro FETA M92 is designed for demanding astrophotography systems where focus accuracy, sensor tilt and precious back-focus space all matter. Its three independently driven adjustment points can move together as a high-precision electronic focuser or separately to correct imaging-train tilt. With suitable software, the correction process can be integrated into a NINA sequence for a genuinely automated imaging workflow.

WandererAstro FETA M92: focus and tilt under precise electronic control

Fast optical systems and large sensors make even small spacing or tilt errors visible. The FETA M92 gives advanced imagers a controlled way to address those errors without relying on repeated manual adjustments. Its patented three-point mechanism provides 4 mm of total travel, 236,467 steps per millimetre and an effective positioning ability of 0.2 µm.

• Three functions in one: electronic focusing, three-point tilt correction and back-focus adjustment.
• Automatic tilt workflow: works with WandererEmpire, NINA and the Hocus Focus Aberration Inspector.
• Large-imaging-train capacity: rated for up to 8 kg with the load's centre of gravity 100 mm from the FETA M92.
• Ultra-low profile: 20 mm overall body thickness and only 15 mm between the recessed M92 mounting surfaces.
• Wide optical path: M92×1 female threads and twelve M3 bolted mounting points on both sides.
• Flexible included interfaces: supplied adapters provide M92 male, M85 male and M85 female connection options.
• Remote-observatory ready: fixed mechanical zero with automatic zero calibration, a fully enclosed light-leak-resistant structure and operation from -30°C to 50°C.

How the FETA M92 works

Synchronised movement for electronic focusing

For focusing, all three drive points move together. The average position becomes the equivalent focuser position, which can be controlled through the integrated ASCOM focuser driver. This allows the FETA M92 to participate in familiar autofocus routines in NINA and other ASCOM-compatible imaging software.

Independent movement for tilt and back-focus correction

For tilt adjustment, the three numbered points move independently. WandererEmpire provides a live visualisation, direct movement controls, 0.001 mm software input resolution and five user-definable presets. Presets can be useful when an imaging system needs known corrections after a meridian flip, target change or camera-angle adjustment.

Important: focusing and tilt adjustment share the same 4 mm mechanical travel. The greater the applied tilt, the less travel remains available for focusing.

Automatic tilt correction with NINA and Hocus Focus

WandererAstro's automatic tilt workflow uses the Aberration Inspector in the NINA Hocus Focus plugin. After the inspection data is saved, WandererEmpire reads the result and calculates movements for the FETA M92's three correction points. The process can be repeated until the field is optimised.

The supplied NINA plugin adds advanced-sequence instructions for connecting the device, applying a stored preset and triggering automatic adjustment after an Aberration Inspector run. This makes it possible to place tilt checking and correction inside an automated imaging sequence.

Software requirement: the manufacturer's current automatic-tilt routine is available only through NINA with the Hocus Focus plugin. WandererEmpire and the required ASCOM driver run on a Windows imaging computer.

Designed for large sensors and substantial imaging trains

The FETA M92 supports a payload of up to 8 kg when the centre of gravity is positioned 100 mm from the unit. Its fully enclosed structure is designed to prevent direct light entering through the mechanism, while the approximately 750 g body keeps the additional load comparatively low for a professional M92-class device.

A fixed mechanical zero and automatic zero detection improve repeatability when the system is used unattended. WandererEmpire can also manage up to six FETA M92 units on one computer, making the design especially relevant to multi-telescope and remote-observatory installations.

Low-profile M92 and M85 integration

Both the telescope and camera sides have a recessed M92×1 female thread as standard. The distance between those two mounting faces is 15 mm, although the complete body is 20 mm thick. Two adapters are included and can be fitted to either side to provide M92 male, M85 male or M85 female interfaces. With both included adapters installed, the effective optical length is 20 mm.

Each face also carries twelve M3 threaded holes for secure bolted adapters. Optional solutions announced by WandererAstro include M68 and M72 female bolted adapters, Moravian C3/C4/C5 interfaces and kits for Takahashi Epsilon and FSQ-106 systems. More interfaces are under development.

The FETA M92 can be stacked with a WandererRotator for a combined focuser, tilt adjuster and camera rotator system with an overall thickness of approximately 35 mm, depending on the exact configuration.

Installation limits to check before ordering

• Maximum engagement for an M92 male thread is 7 mm. Use a suitable spacer if the accessory thread is longer.
• Maximum screw engagement in the M3 mounting holes is 5 mm.
• The bolted mounting surface is recessed by 2.5 mm and has an outer diameter of 109 mm.
• If the stop ring on an M92 male accessory is larger than 109 mm in diameter, include the additional 2.5 mm recess when calculating optical spacing.
• The marked Telescope Side and Camera Side must be oriented correctly when the unit is used for tilt adjustment.

Typical FETA M92 applications

WandererAstro demonstrates the FETA M92 on systems ranging from compact Petzval refractors to large professional reflectors. Published examples include the PlaneWave DR350, Takahashi TOA-150, Epsilon 130/160/180, FSQ-130 and FSQ-106, SkyRover 130 APO Pro, William Optics RC16, Astro-Physics RH305 and Askar 65PHQ. The correct adapter set and available back focus must always be confirmed for the individual telescope, corrector, camera and accessory train.

Specifications

What's included

• WandererAstro FETA M92
• Adapter 1: converts either side to M92 male or M85 female
• Adapter 2: converts either side to M85 male
• 1 mm M92 spacer for connection to the WandererRotator Pro V2
• 1 m DC5521 power cable
• 1 m USB Type-A to screw-lock USB Type-C cable
• M3×6 countersunk hex screws
• Flat-head screwdriver for the Type-C locking screws

Please note: a 12 V DC power supply is not shown among the included items and is therefore not included. Telescopes, cameras, rotators, filter wheels and all other equipment shown in the application photographs are for demonstration only.

Instruction Manuals

Official documentation for the WandererAstro FETA M92 is supplied in English.

Software & Drivers

Download the current WandererEmpire control software, ASCOM components and USB drivers from WandererAstro.

Important optical-performance note

The FETA M92 can correct imaging-train tilt, but it cannot correct telescope collimation or every source of poor star shape. Final field quality also depends on the telescope, corrector spacing, collimation, camera-sensor alignment, guiding, seeing and the accuracy of the Aberration Inspector measurement. For best results, confirm the complete mechanical interface and back-focus calculation before installation.