| Designed to work with most Celestron 8" and 11" Schmidt-Cassegrains. Not for the 8" Ultima 2000, older Ultima 8 PEC, or Ultima 9.25. It will also work with the non-GPS NexStar 8. However, the focuser will hit the drive base of NexStar 8, preventing the scope from reaching the zenith when the focuser is attached. For the non-GPS NexStar 8, the #2458 focuser would be a better choice. The focuser consists of a DC motor and hand control, plus two plastic replacement focusing knobs (one for 8" scopes and a second for 11" scopes) and two plastic focusing collars (again, one for 8" scopes and a second for 11" scopes). The focusing knob of the telescope is removed using the supplied Allen wrench and the appropriate 8" or 11" focusing knob is installed in its place. The appropriate focusing collar is then attached to the rear cell of the telescope, around the new focusing knob. The collar installs in minutes using a supplied Allen wrench. The push-on DC motor slips over the focusing collar. A rubber O-ring inside the motor provides a secure grip on the focusing knob that’s centered within the focusing collar. The motor is held in place on the focusing collar by a nylon thumbscrew in the motor housing. The motor can be easily removed for traveling or storage. The motor has electromagnetic braking for very precise control and the O-ring gripping the focusing knob acts as a slip clutch to prevent damage from exceeding the normal telescope focuser travel. The telescope focuser can still be used manually if the electric focus motor is removed from the focusing collar, which can be done in only 10-15 seconds. A small hand control box plugs into the coiled cord permanently attached to the push-on motor. The control box holds a 9-volt battery (not supplied) that will power the focuser for 6 to 8 months of normal use. Pushbuttons control the direction of focuser travel, while a variable speed control on the hand control adjusts the focusing speed. The focus motor weighs only about 5 oz., so no counterweights are needed to balance your scope with the focuser installed.
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