Vixen AP Equatorial Mount Instruction Manual page 44

APPLICATION
Now, Sigma Octantis gets out of place from the designated position but it is not necessary to correct for it at this stage.
Since there is no mark that points at the South Celestial Pole,
you need to match the polar axis of your AXJ mount with the
S.C.P. using the inconspicuous three stars of Octans in the
same area of the sky.
Your goal is to set Sigma Octantis to the edge of the line on
the side of 2014, and both Tau and Chi Octantis are to be set
to the middle of the curved lines of the position scale at the
protruded edge on the side of 15 respectively. (In case of the
year 2014)
The movement of Chi Octantis from
2014 to 2040 by precession.
The locations of Sigma, Tau and Chi Octantis on the position
scales change year by year due to precession of the Earth.
You need to compensate the locations of the 3 stars on the position scales yearly.
Celestial south
Center of polar the alignment scope´s field of view
(Center of the rotational axis of the equatorial mount)
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Turn the polar scope body so that Tau Octantis comes near
to the location of the year 2014 on the scale. And then,
Sigma Octantis will get out of position from the gap between
the lines.
Adjust the red light illumination to be dimmer if the reticle is
too bright to see the 5th magnitude stars Sigma and Tau
Celestial south
★
The movement of Sigma Octantis
from 2014 to 2040 by precession.
★
The movement of Tau Octantis from
2014 to 2040 by precession.