PrimaLuceLab ARCO 3-inch – Field Rotator and Derotator

PrimaLuceLab ARCO 3-inch – Field Rotator and Derotator

The ARCO 3-inch allows you to adjust a camera's framing remotely and, with proper installation, compensate for field rotation. The manufacturer specifies a control resolution of 1 arcsecond per step. This resolution refers to the step size and is not a numerical guarantee of absolute accuracy in the sky.

Its aluminum body is 23 mm thick and has a clear opening of 76.3 mm. It weighs 1,060 g. The mechanical and electrical components are contained within the housing to minimize protruding parts near the camera. The final length of the optical train must also include the selected mounting adapter.

On an equatorial mount, the rotation function allows you to select the field of view without touching the telescope. On an altazimuth mount, the derotation function assists with tracking for long-exposure imaging. Implementation depends on the mount and the control software: the rotator does not replace the mount’s pointing or tracking function.

ARCO is not a standalone device. It must be connected to an ESATTO eyepiece holder or a SESTO SENSO 2 or 3 motor. A single short cable, included in the package, connects it to the dedicated port on that device for control and power. It therefore does not require a separate USB cable or external 12 V power supply at the rotator.

The mechanical connection depends on your eyepiece holder. For example, the manufacturer specifies adapter PL3600458 for the 3-inch ESATTO and PL3600459 for the 4-inch ESATTO. With a SESTO SENSO mounted on the eyepiece holder, the optional M63×1 or M86×1 interfaces allow for certain connections to a corrector or an eyepiece holder equipped with the corresponding female thread. These adapters are mounting options.

On the camera side, the ARCO 3-inch model features a male M81×1 thread. The M81 adapters in the product line then allow for connection to T2, M48, M54, M57, M68, M72, or a 2-inch slip-on fitting, depending on the specific model chosen. It is important to distinguish between male and female versions; a common nominal diameter does not guarantee compatibility between two parts.

PLAY supports rotation in conjunction with other PrimaLuceLab equipment. The ASCOM driver allows control via compatible third-party software. The manufacturer also provides control via EAGLE, a Windows PC, or a smartphone and tablet using the associated system’s Wi-Fi. Before setting up the mount, be sure to verify the required control unit, the mechanical ring, and the camera output—rather than treating ARCO as a simple, standalone USB accessory.

Technical specifications

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