PrimaLuceLab SESTO SENSO 3 Robotic Focus Motor

SESTO SENSO 3 Robotic Focusing Motor

The PrimaLuceLab SESTO SENSO 3 motorizes an external rack-and-pinion or Crayford-style eyepiece holder while still allowing for manual operation.

Its built-in encoder tracks the axis's movements when the motor is active. This allows for manual wheel operation without losing the motor's position. This feature distinguishes the third generation from a simple drive system, in which the position would be estimated solely based on the number of steps.

The Automatic Position Recovery feature can return the focus to its previous position if movement is detected. The recovery time is adjustable from zero to twenty seconds. The manufacturer notes, however, that the encoder detects axial movements, not internal slippage within the eyepiece holder, which does not result in such movement. It therefore does not replace proper mechanical adjustment.

SCC2 Mounting and Mechanical Compatibility

The Self Centering Clamp 2 system attaches directly to 37-mm interfaces and uses the included adapters for diameters of 25, 26, and 33 mm. Six differently colored sleeves are used to couple the focus axes. It is important to distinguish these small coupling diameters from the outer diameter of the SCC2 system itself.

A resolution of 0.7 micrometers per step is specified for an eyepiece holder with a 1:10 reduction ratio. This specification must be maintained and cannot be considered a universal guarantee for all mechanisms. Compatibility applies to external rack-and-pinion or Crayford eyepiece holders, not automatically to every internal focusing system in a telescope.

Controls and Accessories

The USB-C port allows control from a Windows computer or an EAGLE. PLAY provides position control and autofocus functions; ASCOM drivers also enable integration with compatible third-party software. The built-in Wi-Fi network provides access to the Virtual HandPad on a smartphone or tablet, particularly for visual observations without a computer.

A dedicated port connects to an optional ARCO rotator. DARK mode dims or turns off the indicator lights. With a compatible EAGLE, GHOST mode allows for communication without a USB cable. One input accepts an optional temperature sensor to enable focus compensation after calibration, using the appropriate software.

Content announced by PrimaLuceLab

The motor comes with 25, 26, and 33 mm interface adapters, six coupling sleeves, a USB-C-to-USB-A cable, a 12-V power cable with a cigarette lighter plug, hex keys, and a quick start guide. The eyepiece holder, the ARCO rotator, and the temperature probe should not be included in this list: they correspond, respectively, to the mechanism to be equipped and to optional accessories.

Technical specifications

PrimaLuceLab Official Fact Sheet

Examples of compatible eyepiece holders

The manufacturer specifically mentions the SkyWatcher EVOSTAR, EVOLUX, ESPRIT, Newton, and Quattro; the Takahashi FSQ85 and FSQ106 with fine-focus knobs; and the Baader SteelTrack eyepiece holders. The mounting diameter and the coupling socket must match the eyepiece holder actually installed.

Manufacturer's illustrations