Motofocus For Meade 8", 10", and 12" LightBridge Dobsonians with single-speed focusers

This JMI Motofocus electric focuser is designed for use with the GSO (Guan Sheng Optical Co. Ltd. in Taiwan) Crayford focusers used on Meade 8", 10", and 12" LightBridge Truss-tube Dobsonian reflectors.

The JMI electric focuser can only be used with GSO manual focusers on Meade LightBridge scopes that do not have a dual-speed microfocuser. These focusers have their focus knobs and connecting drive shaft lined up midway between a focuser tensioning screw above the drive shaft and a brake tensioning screw below the drive shaft. The correct knob/tensioning screw alignment is shown in one of the feature images below. This JMI focuser will not work with any other GSO/Meade focuser knob/tensioning screw alignment other than the one shown.

The focuser consists of a tiny DC motor with mounting bracket, a replacement focusing knob with a brass drive gear, hand control, and all necessary mounting hardware.

One of the focusing knobs is removed using the supplied hex-head wrench and replaced with the new geared knob. The two tensioning screws in the focuser housing are also removed. The focus motor and bracket are attached to the focuser housing using two supplied screws (the brake tensioning screw is spring-loaded) which take the place of the tensioning screws you removed. The motor's gear engages the geared focus knob and you are ready to use your focuser.

A small hand control box plugs into the motor using a supplied coiled cord. The control box holds a 9-volt battery (supplied) that will power the focuser for 6 to 8 months of normal use. Pushbuttons control the direction of focuser travel, while a three-position slide switch variable speed control adjusts the focusing speed. The slow and medium focusing speeds automatically switch to high speed focusing if the focus button is held down for more than three seconds. The motor has electromagnetic braking for very precise control.