Charleston Lake
Imaging the Night Sky from Ontario Canada
Ultima PEC / Electronic

Celestron Ultima 8 PEC
The Ultima 8 PEC is highly regarded for its precision Byers wormgear set. Along with the superb mechanical system, the electronics allow four tracking rates (Sidereal, Lunar, Solar and King) as well as the ability to correct for Periodic Error.

The electronic circuitry for the Ultima PEC was designed and built (for Celestron) by Tangent Instruments.  
Tangent was also the same company that brought the Digital Setting Circles to the consumer market, the Celestron Advanced Astromaster, the JMI-NGC Max, Lumicon SkyVector and many others were Tangent made.  
The Ultima 8" PEC telescope uses a totally cordless DC Servo quartz drive system with hand controller. The system electronics incorporate PEC (Periodic Error Correction) with an easy 4 minute recording cycle, highly accurate worm gear drive, four tracking rates including King, sidereal, lunar and solar and a slewing speed of 400% sidereal rate. 
The following images depict the circuitry employed by the Ultima 8 PEC. Note that the older versions used a different circuit board than the newer versions. The newer version uses a motor with Hall Effect sensors for velocity feedback, the same motors as are used in the Ultima 2000 tracking.

Circuit Tracing
Ultima 8 PEC Controls
Newer variant Ultima PEC circuit (1997)
Older variant Ultima PEC circuit (1991)
Latest Circuit Board - Ultima 8 PEC. This circuit uses a PIC16C57 microcontroller for PEC and closed loop velocity control functions
Older circuit with open Loop Velocity Control. This variant had only two wires from the board to the motor.
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(Original Celestron Document)
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