Software Bisque Paramount 6 Series - Periodic Error Correction Tab

Paramount GEM User Guide
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Show Status Tab Parameter
Description
Current Encoder
Shows the current encoder position for both axes. For each axis, the
current encoder value changes when mount is tracking and remains fixed
when not tracking.
Non-sidereal Rate
Shows a number that represents the incremental non-sidereal tracking
rate (above or below the sidereal rate).
When the mount is tracking at the sidereal rate, the HA and Dec values
are zero. If either rate is non-zero, the mount is tracking at a non-sidereal
rate.
See the Set Track Rates command in TheSky Professional User Guide
details about setting tracking rates for objects such as comets, satellites
and minor planets.
Status
Shows an internal motor status number.
Motor
Shows the motor status number.
Control State
A number that indicates the current “state” of the control system.
Servo State
A number value that indicates the current “state” of the DC Servo motor.
Joystick Index
A number that shows the joystick’s index position.
Seconds to Software Limit
The number of seconds of time until the mount tracking to a slew limit.
At that point, sidereal tracking is turned off. Slew the mount away from
the limit to resume tracking.
On-Axis Encoder
The value of the hour angle and declination on-axis encoder. This
parameter is displayed in blue when no on-axis encoder is present.
On-Axis Encoder Raw
The encoder value read directly from the encoder read head.
Periodic Error Correction Tab
The Periodic Error Correction tab is used to generate and manage periodic error curves for the Bisque TCS control
system. The Bisque TCS PEC Table tab is used to retrieve, save, delete, and view the periodic error correction
curve. The Compute PEC Curve tab is used to determine the optimal periodic error curve based on mount tracking
data.
The Paramount has precision worms and gears that slew the mount’s axes and track the earth’s relative motion
compared to the stars. As the worm rotates, imperfections in the drive system (on the order of one twenty-
millionths of one inch) introduce a predictable “back and forth” drift at the eyepiece.
This drift is called periodic error and is present in all worm and gear drive systems. The mount’s periodic error can
be virtually eliminated using periodic error correction. Here is an overview of the periodic error correction process.