9
1. Keeping one hand on the telescope optical tube, loosen
the R.A. clutch lever
(Figure 15). Make sure the Dec.
clutch lever is tightened, for now. The telescope should
now be able to rotate freely about the R.A. axis. Rotate it
until the counterweight shaft is parallel to the ground (i.e.,
horizontal).
2. Now loosen the counterweight lock knob and slide the
weight(s) along the shaft until it exactly counterbalances
the telescope. That’s the point at which the shaft remains
horizontal even when you let go of it. Once balance is
achieved, retighten the counterweight lock knob.
3. To balance the telescope on the Dec. axis, first tighten
the R.A. clutch lever, with the counterweight shaft still
in the horizontal position. Then with one hand on the
telescope optical tube, release the Dec. clutch lever
and check for any rotation. If there is some, you’ll need
to adjust the telescope forward or back in the saddle
or in its tube rings until it remains horizontal when you
carefully let go of it. (You will likely have to swing the R.A.
axis so the telescope is back on top of the mount before
making this adjustment.)
The telescope is now balanced on both axes. When you loos-
en the clutch lever on one or both axes and manually point the
telescope, it should move without resistance and should not
drift from where you point it.
NOTE: For imaging, it is recommended that the mount
be slightly IMBALANCED – weighting the R.A. axis to the
EAST and the Dec. axis in either direction. The imbalance
should be very slight and should be implemented after
you have found the correct balance point using the above
procedure. This weight offset keeps a minimal load on the
gears at all times, which improves guiding behavior.
So for the R.A. axis, if the telescope is on the west side of the
mount, slide the counterweight down the counterweight shaft
(which is on the east side of the mount) a bit – 3 centimeters
or so should be enough. If the telescope is on the east side of
the mount, slide the counterweight up the shaft by the same
distance.
4. Polar alignment
The HDX110 EQ-G mount can be polar aligned either with aid
of the optional, externally mounted polar-axis scope (avail-
able from Orion) or by the iterative polar alignment routine in
the SynScan hand controller. The iterative method does not
require the polar scope, and it can be done even without direct
visual access to Polaris (in Northern hemisphere) or Octans
(in Southern hemisphere). The iterative method is the more
accurate of the two methods.
4.1 Preparing the Mount for Polar alignment
1. Set up the mount as directed in Part 2. We recommend
performing the polar alignment with the telescope and
other equipment installed.
2. Referring to
Figure 12, slightly loosen the primary
locking knob and the two azimuth locking bolts, then
use the azimuth adjustment knobs to rotate the mount
until the azimuth locking screws are centered in the slots
(
Figure 11). Lightly tighten the azimuth locking screws.
3. Loosen the altitude lock knobs and altitude lock bolts,
then lightly tighten them.
4. Tighten the primary locking knob and then loosen it 1/4
turn.
5. Move the tripod to roughly align the R.A. axis to true
north (or south for use in Southern hemi sphere).
6. Install the handle on the altitude jackscrew and use it to
set the latitude scale to your local latitude
(Figure 14).
4.2 Polar alignment using the synscan Hand
controller
1. Select 2-Star or 3-Star alignment to align the mount for
GoTo operation, then perform the po lar-alignment routine
detailed in the SynScan Hand Controller manual. Repeat
these operations several times until the SynScan hand
con troller reports a small polar alignment error after the
2-Star alignment or 3-Star alignment.
2. At the end of the polar-alignment routine, tighten the
primary locking knob, and then tight en the azimuth
locking screws, the altitude lock knobs, and the altitude
lock bolts. You should observe the final alignment star in
the eyepiece while alternately tightening these symmetric
knobs and screws, to try to minimize the movement of
the alignment star in the eyepiece while locking things
down.
3. It is recommended to remove the jackscrew handle after
the polar-alignment is completed, to avoid inadvertently
hitting it or having a cable catch on it, either of which
could disturb the polar-alignment.
4.3 Polar alignment using the Optional Polar-axis
scope
Instructions for using the polar-axis scope are included with
that accessory and are available for viewing or download on
our website.
Figure 16 shows the polar-axis scope installed
on the mount.
Figure 16.
Optional polar-axis scope installed on the
HDX110.
