41
PART XI : ADVANCED FUNCTIONS
Notes:
• It is recommended to use a high-power telescope and a reticle eyepiece for the PEC train-
ing. A digital eyepiece with a computer is preferred.
• For the equatorial mounts that support PPEC (such as the AZ-EQ6 GT and EQ8 mounts),
an autoguider can be used to replace manual guiding in PEC training process. In such
cases, it is recommended to turn on the autoguiding for at least one minute before starting
the PEC training process. The total time for the PEC training of these mount can be as long
as two cycles of the period error.
Once PEC training is completed, access the menu “
Setup\Tracking\PEC+Sidereal
” and press
the
ENTER
key to start the PEC replay, that is, start to compensate the period error. Choosing
other items in the menu “
Setup\Tracking
” will turn off the PEC.
PEC Replay
11.5 Periodic Error Correction (PEC) for EQ Mount
1.
Polar align the equatorial mount accurately, then perform a star alignment.
2.
Choose a star close to the celestial equator, point the telescope towards it and start the
mount tracking. Center the star in the telescope’s eyepiece.
3.
Access the menu “
UTILITY FUNCTION\PEC Training
” and press the
ENTER
key, the screen
will display “
Select Speed: 1)0.125X 2)0.25X
”. This is the speed used to adjust the posi-
tion of the star in the FOV of the telescope when a user presses the
Left
or
Right
direction
key on the SynScan hand control. Choosing a 0.125X sidereal rate is recommended for a
smaller FOV of telescope, and a 0.25X sidereal rate is recommended for a wider FOV of
telescope. Press the “
1
” or “
2
” key to make a selection and proceed to the next step.
4.
The screen will display the elapsed time. Use the
Left
and
Right
direction keys to con-
trol the mount and keep the star at the same spot in the FOV of the telescope until the
SynScan hand control stops displaying the time. The total time for this training process
depends on the mount model.
The periodic error correction function applies to equatorial mounts only.
All equatorial mounts have periodic tracking error, which is not critical for visual observations
but might lower the picture quality of long exposure astrophotography. The SynScan hand
control has the periodic error correction (PEC) function to improve the tracking performance
for astrophotography.
Depending on the model of the equatorial mount, there are two types of PEC. One is soft-
ware based PEC (SPEC), which applies to Sky-Watcher’s EQ3/EQ5/HEQ5/EQ6 Pro mount.
The other is permanent PEC (PPEC), which applies to Sky-Watcher’s AZ-EQ6 GT mount and
EQ8 mount. The SynScan hand control can detect the mount model and choose the corre-
sponding PEC algorithm.
The PEC function is a training-replay process.
PEC Training:
