RB Focus Merlin 3.0 Electronic Focuser

It mounts on your telescope's existing focuser with the bracket format you choose: Standard format (Sky-Watcher models with dual-speed focuser, TS, GSO, William Optics and similar), Large format (Feather Touch and similar), Mak 127 base, SCT base (Mak 150 and larger; RB Focus lists Sky-Watcher Maksutovs and Celestron and Meade SCTs and asks you to confirm the size), or the Takahashi adapter (27 mm with 3.5 mm shaft).

The Merlin 3.0 requires a 12V DC power source. The power connector is a standard 2.1 x 5.5 mm DC jack. Please note that a 12V power adapter is not included in the box and must be supplied separately.

Yes. Choose the SCT base version. RB Focus suggests the mobile app for focusing during visual or planetary observing without touching the telescope.

The external temperature sensor allows your autofocus software to perform temperature compensation. As the ambient temperature changes overnight, a telescope's metal tube can expand or contract, causing the focal point to shift. By monitoring this temperature change, software like N.I.N.A. or SGP can be configured to automatically trigger a new autofocus run after a set temperature drop, ensuring your images remain sharp all night.

For automated focusing within an imaging sequence you need a computer running ASCOM or INDI capture software. For manual electronic focusing, RB Focus's mobile app connects over Bluetooth.

Yes. RB Focus says it has been tested with color cameras and DSLRs as well as mono cameras, and William Optics focusers are among those covered by the Standard bracket format.

RB Focus says the DirectDrive transmission lets you focus manually even when you have no computer at hand, and the mobile app allows manual electronic focusing. RB Focus does not say whether the focuser knob can be turned by hand with the motor fitted.

RB Focus's Sensorless AutoHoming automatically calibrates the focuser in several directions. If the tube is moved by accident or racked in by hand, it returns the focuser to the last focus point applied by your capture program. A magnetic-field sensing system also ensures correct tension on the focuser mechanism, avoiding slippage.

No, it is designed for straightforward setup. After installing the ASCOM driver, the Merlin 3.0 appears as a standard focuser in your software. The driver provides simple, minimal settings, allowing you to connect and start an autofocus run quickly without needing to understand complex parameters.

The Merlin 3.0 incorporates a system called InteligentSilentDrive™, which actively adjusts the motor's force for completely silent operation.

The DirectDrive system connects the motor shaft directly to the focuser pinion via a coupler. This eliminates the need for belts or gears, which can introduce backlash (a small amount of "slop" or delay when changing direction). RB Focus says this avoids the mechanical play common in other products.