Vixen SPHINX SXD Mount - Manual (Page 43)

Page 44
PEC
The Equatorial mount (with drive motors) is designed to precisely track the motion of
celestial objects. With the equatorial mount you may notice that stars in the field of view
of your telescope are moving back and forth very slowly over a period of time (e.g. 10
minutes for GP2 and GPD2). This is a result of viewing them at very high magnification.
It is unavoidable since the equatorial mount is driven via gear wheels. However, it may be
annoying when you are observing at high magnification.
The PEC (periodic error correction) function electrically rectifies this phenomenon in the
equatorial mount. You can correct a drifting motion of the equatorial mount with manual
operation of the buttons on the controller and memorize it in the STAR BOOK. It will
enable you to track more precisely by using the recorded motion*.
* The tracking accuracy relies on how you correct irregular motions. The tracking may
deteriorate if the correction is made inaccurately.
Start the PEC recoding
(1) Position a guide star you want to use for the PEC recording in the center cross hairs of
your guiding eyepiece. (You can use a Vixen GA-4 illuminated guiding adapter or a Vixen
Or-12.5mm with illuminated reticle as a guiding eyepiece.) Use an eyepiece which yields a
magnification of approximately 200 power.
(2) Confirm the current screen is in SCOPE MODE. Pressing the Chart key will change
the screen to SCOPE MODE when you are in CHART MODE.
(3) Press Menu to display the System Menu. Move the cursor to PEC with the
keys
and press Select to enter the PEC screen.