PrimaLuceLab ESATTO 4" Robotic microFocuser

Crayford-Style Design with a 10 kg Payload Capacity

The ESATTO 4" is a Crayford-style focuser with 40 ball bearings, which PrimaLuceLab designed for a very high load capacity (up to 10 kg) with no flexure. The manual explains that a focuser without enough load capacity lets heavy imaging trains slip out of focus, especially near the zenith.

This high-load design introduces a minor trade-off: you may notice a very small shift of the image during focuser movement, which the manual says is normal and caused by the modified Crayford design that gives ESATTO its higher load capacity. Minor variations in step position after many autofocus runs are also normal; if focus drifts, run a new calibration in PLAY.

35mm of Draw Tube Travel at 0.04 Micron Resolution

With 35mm of total travel, the ESATTO 4" has the longest travel of the ESATTO family, with a step resolution of 0.04 microns.

A 102.2mm Free Aperture in a 65mm Low-Profile Body

The ESATTO 4" is designed for large professional telescopes and for astrographs with a large corrected image circle that need a focuser with a large free aperture: 102.2mm. The design is low profile, with 65mm thickness (91mm with internal flange).

M110x1 Threads for Secure Camera and Telescope Connection

The draw tube of the ESATTO 4" ends in an M110x1 male thread. PrimaLuceLab's optional adapters include M110 to M68 and M110 to M98 with stop ring, M110 to M92 and M110 to M95 female, M110 extension tubes, and telescope adapters for the Takahashi FSQ-106, FSQ-106EDX IV and TOA130 and Officina Stellare ProRC, RiDK and RiFAst.

Remote Control via USB-C, WiFi Virtual HandPad, and ASCOM

The ESATTO 4" offers multiple methods for remote control. A reversible USB-C port connects to any Windows computer or a PrimaLuceLab EAGLE, for control with PLAY or through the ASCOM driver. It can be powered over USB, but if a computer's USB ports deliver less than 0.5A the focuser may stop abruptly, and the 12V input must be connected as well.

For computer-free operation, the ESATTO 4" creates its own WiFi network. You can connect directly to it from any smartphone, tablet, or laptop and use the included Virtual HandPad to move the focuser and save up to 9 focus positions, also for visual use. The status LEDs are dimmable and can be turned off.

Automatic Focus Compensation with Internal and External Probes

To combat thermal focus shift during an imaging session, the ESATTO 4" is equipped with an internal temperature sensor that reads the motor temperature. For focus temperature compensation, the optional external temperature probe can be connected; the ESATTO then reports temperature, and autofocus can be set to run after a temperature change.

Automated Calibration with Internal Position Sensors

The ESATTO 4" features internal sensors for automatic detection of the maximum inward and outward travel limits. This means the focuser arrives pre-calibrated from the factory and does not require a manual calibration routine to learn its travel range. This data is stored in the focuser's memory, so switching computers needs no new calibration.

Seamless Integration with the ARCO Robotic Rotator

The ARCO port connects the optional ARCO camera rotator and field de-rotator with one short interconnect, without additional USB or 12V power cables; the Adapter ESATTO 4" for ARCO 3" joins the two. ARCO lets you set the camera angle remotely and, with an alt-az mount, de-rotate the field without an equatorial wedge.

A Custom Solution for the Takahashi FSQ-106 Astrograph

The FSQ-106's internal corrector is so large that it requires a very large focuser, and the ESATTO 4" is the ideal focuser for it. The optional Adapter ESATTO 4" for Takahashi FSQ-106 (PL3600310) ensures the ESATTO 4" combination has the same thickness as the original focuser, allowing you to reach focus without issue. It also includes an adapter that converts the ESATTO's M110x1 draw tube thread to the M92x1 female thread on the original Takahashi focuser, so you reach focus with the same photographic adapters you used before. PL3600310 is not compatible with the FSQ-106EDX 3 and 4; a separate Adapter ESATTO 4" for Takahashi FSQ-106EDXIV exists.

ESATTO 4" vs. 3" and 2": Matching Aperture to Your Telescope

All ESATTO models share the control features; they differ in size, aperture and load.

• ESATTO 4": 102.2mm free aperture, 35mm travel, 10 kg payload, 2050 g, for observatory-class telescopes and astrographs like the FSQ-106.
• ESATTO 3" and 2": 76.3mm free aperture, 25mm travel and 8 kg (1345 g) for the 3"; 51mm, 15mm and 5 kg (835 g) for the 2", the recommended model for SCT and EdgeHD telescopes.