PrimaLuceLab ESATTO 2" Robotic microFocuser

The ESATTO 2" Robotic Focuser: An All-in-One Solution

The ESATTO 2" is an all-in-one focusing solution, integrating the motor and electronics directly into the focuser body, so no external motor controller is needed. With the optional adapters it can replace the standard focuser of many telescopes.

You can control it from an EAGLE or Windows computer over USB, or from a smartphone, tablet or computer over WiFi with the Virtual HandPad.

Mechanical Design: A 5 kg Capacity Crayford System

The ESATTO 2" uses a Crayford-style design, which PrimaLuceLab chose to deliver smooth and precise focusing, modified to give a higher load capacity than standard Crayford focusers: 5 kg. The manual explains that a focuser without enough load capacity lets heavy imaging trains slip out of focus, especially near the zenith, and that ESATTO's load capacity addresses this.

The manual notes that a very small image shift during focuser movement is normal with this modified Crayford design. It also says minor variations in step position after many autofocus runs are expected, particularly with very fast optics: if the focus position drifts over time, run a new automatic calibration in PLAY.

Performance: 15 mm of Travel at 0.04 µm/step Resolution

The focuser offers a total draw tube travel of 15 mm, with a step resolution of 0.04 microns per step.

Because 15 mm is shorter than the travel of many standard focusers, the manual shows how to use the telescope's back focus and extension tubes so the focus position falls within the ESATTO's travel.

Physical Profile: The 67 mm Body for SCT and EdgeHD Telescopes

The ESATTO 2" has a compact 67 mm body. The 2" is the recommended model for Schmidt-Cassegrain and EdgeHD telescopes because its lower thickness avoids back focus problems and its 51 mm free aperture is larger than the baffle tube of these telescopes.

Using the ESATTO 2" on an SCT or EdgeHD lets you focus with the external focuser instead of moving the primary mirror, which the manual says avoids image shift and mirror flop; on telescopes with a primary mirror lock you can lock the mirror.

Connectivity: The M56x1 Draw Tube and Optional Adapters

The ESATTO 2" draw tube features an M56x1 male thread, providing a secure, threaded connection point for your camera and accessories. PrimaLuceLab offers optional adapters for this thread.

• Telescope Adapters: Adapters connect the ESATTO 2" to many telescopes, including those with the standard SC thread (PL3600209) (Celestron 8"/9.25" SCT, EdgeHD 8") and the large 3.3" SC thread (PL3600212: Celestron 11"/14" SCT, EdgeHD 9.25"/11"/14").
• Camera Adapters: Adapters from M56 with stop ring to T2, M48, M54, M57 and SC threads connect cameras and accessories; a 2" visual back is also available.

Control Software: USB-C, WiFi, PLAY, and ASCOM Integration

The ESATTO 2" offers multiple methods for remote control. For a wired connection to an EAGLE or any Windows computer, use the included USB-C cable. This allows you to control the focuser via PrimaLuceLab's dedicated PLAY astrophotography software or through third-party software via the ASCOM driver.

For wireless control, the ESATTO 2" has built-in WiFi, creating its own network. You can connect to it from a smartphone, tablet, or computer and use the included Virtual HandPad, without an EAGLE or computer. The Virtual HandPad moves the focuser and saves up to 9 named focus positions, which you also find when controlling the ESATTO over USB.

Temperature Compensation: Internal Sensor and External Probe Port

As temperature changes during a session, focus can shift. The ESATTO 2" has an internal sensor that reads the motor temperature (values from 10 to 50 °C are normal); for focus temperature compensation you connect the optional external temperature probe.

With the probe connected, the ESATTO reports temperature with its position, and the manual's autofocus examples include running autofocus after a temperature change.

Calibration: Automatic End-of-Travel Detection

Thanks to internal sensors, every ESATTO is already calibrated, with the minimum and maximum draw tube positions set. The calibration data is stored in the ESATTO's memory, so you don't need to calibrate when switching computers.

You can run a new calibration from PLAY (it usually takes 2 to 3 minutes) or from the Virtual HandPad settings. This is recommended if the focus position drifts after many autofocus routines, especially when the change exceeds half of the draw tube travel; it resets the internal reference.

System Integration: The Dedicated ARCO Rotator Port

The ESATTO 2" has a port for the optional ARCO robotic rotator. The ARCO is powered and controlled through this port with the ARCO cable, so it needs no separate power or USB cable; it fits with the optional Adapter ESATTO 2" for ARCO 2".

You activate the ARCO with the ARCO enable switch in the ESATTO settings and control both devices from PLAY or through their ASCOM drivers.

Power & Installation: 12V DC or USB-C Power Options

The ESATTO 2" offers flexible power options. It can be powered through the USB-C connection from an EAGLE or computer. If a computer's USB ports deliver less than 0.5A, the focuser may stop abruptly, and you must also connect a 12V power source. For WiFi control without a computer, power it from a 12V supply with at least 1A capacity (or from a USB port of an EAGLE or computer).

The focuser includes a 12V power cable with a cigarette plug (5.5/2.5 connector, positive tip; maximum consumption 350mA at 12V). Installation begins by selecting the correct optional adapter for your telescope, attaching it to the telescope, and then securing the ESATTO 2" focuser to the adapter.

In the Box: Getting Started with the ESATTO 2"

The package contains the ESATTO 2" robotic focuser itself, a USB-C to USB-A cable for computer connection, and a 12V power cable with a cigarette plug for field power. A 2mm Allen key and the ESATTO quick start guide are also included.

To get started, download the latest software package from the PrimaLuceLab website, which includes the Windows driver, PLAY and the ASCOM driver. Connect the focuser to your computer via USB, let Windows detect it, and then install the software. You can then connect to the focuser through PLAY or your preferred ASCOM-compatible software to begin focusing.