The EV-XT 3" Motorized Crayford Focuser from JMI Telescopes is a replacement focusing system for larger Cassegrain telescopes. It is capable of supporting and lifting up to 12 pounds. This is important for astroimaging, astrophotography or when using heavy eyepieces or accessories. The Crayford-style is able to achieve highly precise focusing by its unique metal-on-metal friction system. Since it doesn't rely on tracks and gears, minute adjustments are possible to a degree that rack-and-pinion style focusers are incapable of. The focuser is designed for 10 to 16 inch Cassegrain telescopes with standard output threads.
The DC micro-motor is pulse-modulated from the wired hand contoller running on a 9V battery. Using the 3-speed hand controller eleminates the need to touch the focuser, which can cause unwanted vibrations. A Quick-Release Manual Override allows the dual-speed focuser to be used by hand with the textured adjustment knobs. With a fast-speed travel of 0.58" and fine-focus of 0.064" per knob rotation, precision focusing is easy with or without the controller.
The focuser base can be rotated to accomodate left and right handed users, or for easy access if the telescope orientation changes throughout the skywatch session. The focuser comes with a 2" eyepiece adapter and a 1.25" is also available.