Pec - Vixen AP Equatorial Mount Instruction Manual

APPLICATION
PEC (Periodic Error Correction)
Equatorial mounts with drive motors are designed to precisely track the motion of celestial objects. With the use
of a telescope mounted on the equatorial mount, you may notice that stars in the field of view of the telescope
at high magnification are drifting back and forth very slowly over a period of time (e.g. 600 seconds with the AP
mount) in the direction of R.A. This is caused by the motion of the tracking gear wheels and it is part of the design
of equatorial mounts. The PEC (periodic error correction) rectifies this phenomenon on the equatorial mount and
records the correction electronically.
The tracking accuracy varies in irregular motion and must be corrected as precisely as possible.
Starting the PEC Recording
1
P recisely polar align the mount.
2
Prepare an eyepiece with crosshairs. Center a moderate star in the
field of view of the eyepiece. Put high magnification as high as 200X
and more.
3
Pressing the Mount button will turn up the brightness of the button and it enables you to choose subsidiary
menus. The subsidiary menu appears as you press the left or right direction key each time. Display the "PEC
No Data" with the left or right direction key.
4
Pressing the up or down key will advance the display to "PEC StrtRec?" and the plus and minus buttons
will blink.
5
Press the + button to start a PEC recording. The period of time for the PEC recording is 10 minutes (600
seconds). On starting the PEC recording, the counter starts from 600 (599) and counts down every second
to 0 and repeats. The speed of correction with the left or right direction key is fixed at 0.5 times of sidereal
rate. To cancel the menu, press the minus button.
6
As you monitor the star in the field of view, it begins to shift away from
the center of the crosshairs in direction of the RA tracking. At the point
in time where the deviation is apparent, bring the star back to the center
of the crosshairs with the left or right direction key for correction.
7
A cycle of the PEC recording ends as the 600 seconds has elapsed, but the duration of the recording
continues until you stop it. The old recording data is overridden by new ones.
Note: Be sure to continue more than 10 minutes to make sure to complete one cycle of the PEC recording.
Centering the guide star Centering the guide star
52
DEC axis
Polar axis

Pec

No Data
Pec
StrtRec?
Pec
480 x0.5
Guide Star Guide Star