3
The 8" RC has a 2" linear-bearing Crayford focuser,
which has a stabilizing track on the underside of the
drawtube that provides extra rigidity for carrying
heavy payloads. The tension adjustment knob is on
the underside of the focuser while the larger locking
knob is on top.
The 10" RC also boasts a linear bearing focuser, but
with an oversized housing and a larger 3.3" drawtube
that terminates in a 2" accessory collar. It has a
stabilizing track, too. The tension adjustment knob is
on the underside of the focuser while the larger
locking knob is on top.
Point the telescope so the front end is aimed in the
general direction of an object you wish to view.
Release
drawtube lock knob
so the drawtube can
be moved while turning the focus knobs. Select a
proper diagonal and eyepiece if you are doing visual
observation.
Adjust
the
drawtube
tension
adjustment knob
for a proper tension during adjust
the focus knob. Look through the eyepiece while turn
the coarse focus knob to move the drawtube outward
until you see the image. Turn the fine focus knob until
the image becomes sharp. Go a little bit beyond
sharp focus until the image just starts to blur again.
Then reverse the rotation of the knob just to make
sure you’ve hit the exact focus point. You will have to
readjust the focus when aiming at subjects of varying
distances, or after changing eyepieces.
If the focuser drawtube is fully extended and you are
still unable to achieve focus, you will need to install
one or more extension rings (
see next section
).
Practice this during daytime by aiming the main
telescope tube at a land-based target at least ½ miles
away.
The focuser can be rotated to a desired angle prior to
Drawtube lock knob
Drawtube tension
adjustment knob
Drawtube lock knob
Drawtube tension
adjustment knob
Coarse focus knob
Fine focus knob
Drawtube tension
adjustment knob
Drawtube lock knob
Stabilizing track
Attachment collar
