PrimaLuceLab SESTO SENSO 3 LS robotic focusing motor for telephoto lenses

• Expected to be available in November – please reserve in advance (payment will be made upon availability)
• NEW Compact all-in-one chassis designed to be used with telephoto photographic lenses (Canon, Nikon, and others)
• NEW  Integrated encoder for position tracking and manual movement without losing motor position, with Automatic Position Recovery option
• NEW Lens Gear Clamp (LGC) with backlash-free, gear-driven coupling for precise motorized focusing of photographic lenses without external belts
• High resolution motor with 2 million steps for precise control manual focuser of telephoto lenses
• USB-C connectivity to control from computers with astronomy software
• WiFi connectivity to control it from smartphone or tablet with the included Virtual HandPad, without the need of computer or physical hand pad
• Compatible with PLAY software to control focus position, also with autofocus
• Provided with ASCOM drivers to let you control through third party astronomy software
• ARCO rotator port to directly connect the optional ARCO without the need for additional data or power cables
• DARK mode with dimmable LED lights, that can even be turned off completely
• GHOST mode to remove USB cable when used with EAGLE computer
• Temperature sensor port to automatically compensate focus caused by environmental temperature change
• Developed and manufactured in Italy
• Weight: 515 grams (1.1 lbs)

SESTO SENSO 3 LS is the robotic focusing motor designed specifically for precision motorized focusing of telephoto photographic lenses (Canon, Nikon, and others). Developed and manufactured in Italy by PrimaLuceLab, SESTO SENSO 3 LS builds on the technology of SESTO SENSO 3 and introduces the new Lens Gear Clamp (LGC), a custom mechanical interface that directly connect the motor to photographic lenses to rotates the focus ring of compatible photo lenses with extreme precision and without backlash, eliminating the need for external belts (although a belt is optionally available for lenses with very stiff focus mechanisms) and offering an integrated position encoder that keeps track of motor position even during manual adjustments, with Automatic Position Recovery option. The LGC also features an Arca-Swiss style mount, allowing SESTO SENSO 3 LS to be easily attached to one of the optional PLUS Vixen-style dovetail bars and mounted on any telescope mount equipped with a standard Vixen clamp.

With USB-C and built-in WiFi connectivity, you can control SESTO SENSO 3 LS from your computer or wirelessly via the Virtual HandPad using a smartphone or tablet. Its high-precision motor delivers 0.7 micron per step resolution, making it ideal for both visual observation and astrophotography. Compatible with ARCO rotators, ASCOM drivers, and PLAY software, and supporting EAGLE’s GHOST mode, and DARK mode with dimmable LED lights, SESTO SENSO 3 sets a new standard in robotic focusing systems.

Compact, lightweight and all-in-one design

SESTO SENSO 3 LS features a compact and lightweight enclosure that integrates all control electronics, with all ports conveniently located on the side. The unit includes dimmable status LEDs, which can also be turned off completely to avoid stray light during nighttime imaging sessions with photographic lenses. Connectivity is streamlined and efficient: a USB-C port allows connection to an optional  EAGLE or any Windows® computer using the included USB cable; the dedicated ARCO port enables both power and control of an optional ARCO camera rotator through a single cable; the 12V power port (5.5/2.5mm, center-positive) supplies power to both the motor and internal electronics using the included cigarette lighter-style cable (or with an optional cable for direct connection to the optional EAGLE); and a temperature sensor port lets you connect the optional probe for use with third-party software that supports automatic focus compensation based on ambient temperature changes.

Easy installation with Lens Gear Clamp (LGC)

SESTO SENSO 3 LS features the new Lens Gear Clamp (LGC), specifically designed for telephoto photographic lenses such as Canon, Nikon, and other models with manual focus rings. This innovative gear-based design eliminates mechanical backlash and ensures smooth, precise motorized focusing without the need for external belts. The integrated rubber gear directly engages the lens focus ring, while the Arca-Swiss style mount allows you to secure SESTO SENSO 3 LS to a optional PLUS Vixen-style dovetail bar for perfect alignment. Manual focusing is still possible at any time by rotating the lens’s focus ring, while the integrated encoder keeps track of the motor’s position—even after manual adjustments. This makes SESTO SENSO 3 LS ideal for astrophotographers who want the precision of a robotic focusing motor combined with the freedom of manual control.

If your telephoto lens does not include an L-bracket with photo thread for mounting to the optional PLUS Vixen-style dovetail bar, we offer an optional Secondary Support for Photo Lenses—a dedicated accessory that ensures proper stability and alignment when using SESTO SENSO 3 LS.

To provide optimal grip on different lens focus rings, SESTO SENSO 3 LS comes with two interchangeable rubber gears: one for lenses with focus rings up to 18mm in width, and one for lenses with focus rings thicker than 18mm. This ensures maximum contact and precision across a wide range of compatible lenses. SESTO SENSO 3 LS is compatible with many photographic lenses, such as (but not limited to):

• Nikkor Z 70-200mm f/2.8 Vr S
• Nikkor Z 100-400mm f/4.5-5.6 VR S
• Nikkor Z 24-120mm f/4 S
• Nikkor Z 24-70mm f/4 S
• And other telephoto lenses with manual focus ring

Integrated encoder: precise control with freedom of movement

SESTO SENSO 3 LS integrates a high-resolution position encoder that tracks the movement of the motor shaft with extreme accuracy. This allows the user to manually rotate the focus ring of the photographic lens, with SESTO SENSO 3 LS installed and powered on, without losing the motor’s reference position. Ideal for astrophotographers who need to fine-tune focus manually before switching to fully automated control, this feature also improves the initial calibration process.Another advantage of the integrated encoder is its ability to detect and compensate for small shifts in focus caused by lens mechanics. With this Automatic Position Recovery function, SESTO SENSO 3 LS can also automatically move the lens focus ring back to the previous position if it is rotated manually or accidentally shifted. You can define a recovery delay (from 0 seconds for instant reaction up to 20 seconds). Please note that the encoder detects motor shaft movements only and cannot account for internal mechanical slips in the lens focusing mechanism.

USB-C connectivity to control it from a computer

SESTO SENSO 3 SC features a modern USB-C port for direct connection to your control device, whether it’s a standard Windows 10 or 11 PC or the EAGLE computer. The USB-C interface offers a range of benefits over traditional USB connections: it’s reversible, making it easy to plug in even in low-light conditions, and it ensures a secure and reliable connection that’s resistant to accidental disconnections—especially useful in mobile or remote observatory setups. Plus, the wide compatibility with standard USB-C cables makes it easy to integrate SESTO SENSO 3 LS into any modern astrophotography workflow without the need for proprietary connectors.

Easy control with PLAY astrophotography software

SESTO SENSO 3 LS integrates perfectly with PLAY, the powerful astrophotography software developed by PrimaLuceLab to simplify and enhance your astrophotography. PLAY provides an intuitive interface that allows you to remotely control the focuser position with precision, directly from your optional EAGLE or standard Windows 10/11 computer. PLAY unlocks advanced capabilities such as AutoFocus, which automatically analyzes the stars dimensions and adjusts the focuser position for optimal focus position. In addition, PLAY includes features like temperature compensation, focus presets, and real-time status monitoring, making it the ideal solution astrophotographers.

Advanced control with ASCOM drivers and third party softwares

Thanks to the provided ASCOM driver, SESTO SENSO 3 LS is fully compatible with a wide range of popular third-party astronomy software, giving you maximum flexibility in how you control your focuser. Whether you’re using applications like NINA, Sequence Generator Pro, MaxIm DL, or others, SESTO SENSO 3 LS integrates smoothly into your existing workflow. This level of compatibility makes SESTO SENSO 3 LS an ideal choice for advanced astrophotographers and observatories who demand both performance and software freedom. No matter which platform you prefer, you can count on SESTO SENSO 3 LS to deliver accurate results night after night.

WiFi connectivity to control it without the need of computer or physical hand pad

SESTO SENSO 3 LS features a built-in WiFi module that creates its own wireless network, allowing you to control the focuser from any smartphone or tablet—no cables or computer required! Simply connect your device to the SESTO SENSO 3’s LS WiFi network and launch the built-in Virtual HandPad. You’ll be able to move the focuser using your smartphone or tablet just like you would with a traditional hand controller. Thanks to convenient preset positions, you can easily save and return to specific focus points—perfect for visual observing as well. WiFi control remains active even when SESTO SENSO 3 LS is connected to a computer, allowing simultaneous control from two devices for added flexibility.

Full compatibility with optional ARCO rotator

SESTO SENSO 3 LS features a dedicated port for direct connection to ARCO, the robotic camera rotator and field de-rotator developed by PrimaLuceLab. With ARCO, you can remotely adjust the rotation angle of your camera to achieve perfect framing of your target. If you’re using an alt-azimuth mount, ARCO also allows you to de-rotate the field during long exposures—eliminating the need for an equatorial wedge. SESTO SENSO 3 LS and ARCO are designed to work seamlessly together, requiring only a single short cable for both power and data. No additional controllers or connections are needed, making it easy to build a compact, fully integrated, and automated imaging system for advanced astrophotography or scientific applications.

DARK mode with dimmable LED indicators

SESTO SENSO 3 LS is equipped with LED indicators on its body that provide useful visual feedback for device status and diagnostics. The LEDs are fully dimmable, and by enabling DARK mode—via PLAY software or the ASCOM driver—you can turn them off completely to preserve your night vision and eliminate stray light during astrophotography sessions. When using SESTO SENSO 3 LS with an optional EAGLE control unit, DARK mode activation can be automated in PLAY: as soon as an imaging sequence starts, all LED lights are automatically switched off, allowing for fully unattended and light-safe operation.

GHOST mode support and firmware updates

When used with an optional EAGLE control unit, SESTO SENSO 3 LS supports GHOST mode, allowing complete operation without needing a USB cable, for a cleaner setup. GHOST mode also acts as a backup communication channel: if the USB cable stops working, you can still access SESTO SENSO 3 LS through the EAGLE and continue your imaging session without interruption. In addition, firmware updates can be easily installed via PLAY software, ensuring your focuser always benefits from the latest features, improvements, and compatibility enhancements.

Temperature sensor port for optional external probe

SESTO SENSO 3 LS supports temperature compensation when used with the optional external temperature probe, allowing calculation of how the focus position shifts as ambient temperature changes throughout the night. Once the probe is connected, you can perform a temperature calibration directly in PLAY to determine the correlation between temperature and focus shift. After calibration, temperature compensation can be applied automatically by PLAY or by third-party software via the ASCOM driver, ensuring stable focus during long imaging sessions—even with very fast focal ratio telescopes (for example faster than f3) and in fluctuating environmental conditions.

Dimensions and weight

SESTO SENSO 3 LS includes all these advanced features in a lightweight, compact all-in-one chassis designed to be installed on your focuser without the need of external brackets. SESTO SENSO 3 LS  weights just 440 gr. (1.0 lbs). See image for product dimensions.

Scope od Delivery

• PrimaLuceLab SESTO SENSO 3 LS robotic focusing motor for telephoto lenses
• Arca-Swiss clamp
• 6mm and 18mm thick rubber gears
• USB-C to standard USB-A cable
• 12v DC cigarette-style plug power cable
• Hex keys for assembly
• Quick installation guide