For reference, the pieces of the polar finder
are shown below (Figure 1).
Figure 1. Polar finder parts.
- Some polar finders come with a metal
washer instead of the plastic washer.
The purpose is to allow the finder to
be rotated, yet held in alignment. The
retaining ring should be tightened just
enough to allow rotation of the finder.
The setscrew in the retainer ring is
meant to hold the retainer at a fixed
position but does not have to be
- The objective tube screws into the back
end (reticle/eyepiece assembly).
Focusing depends on how far in it is
screwed. The focus set ring fixes the
focus point once it has been determined.
Installation of the polar finder is the same
for both the G11 and GM-8 mounts. Unscrew the
cap at the end of the RA clutch knob (don't unscrew
the clutch knob itself), and the polar finder slides
right in. The polar scope's retaining ring
screws on using the same threads that the
clutch cap used. If you intend to leave the
polar scope permanently installed, you no
longer need the clutch cap.
In G11 mounts, the polar finder's focus lock
ring may sit against the RA axis shaft and
prevent the polar finder from being fully
inserted into the RA clutch when the clutch is
fully tightened. In this case, the focus lock
ring outer diameter may need to be reduced so
it can go into the RA shaft, or washers
may be added ahead of the RA clutch to move the
clutch further out. Normally, these thick
spacer washers are provided with the G11, but
may have gotten lost if digital setting circles
were installed, then removed from the mount.
This should not be a problem on mounts with
digital setting circles as the installation of
the RA encoder adds sufficient distance between
the clutch and RA shaft to fully insert the
Figure 2. RA clutch with cover removed, ready
for installation of the polar scope.
Since The polar finder screws into the bottom
of the Losmandy mount RA clutch the polar
finder will rotate when the clutch is
turned (it is not a defect), but this does not
affect use of the polar finder since the clutch
is not normally turned during the polar
To sight Polaris, remove the polar scope cover
opposite the RA clutch knob end of the RA axis.
Looking down the polar axis, rotate the Dec
axis until the hole in the axis is oriented so
that the polar scope is visible. Depending on
your mount's saddle arrangement, this should be
at either 0 degrees Dec or +/-90 degrees.