Orion SkyQuest XX12g Instruction Manual page 11

Counterweight
Counterweight
mounting bolts
Figure 17.
Installing counterweights (XX14g only). Thread two
2.2-lb. counterweights onto each counterweight mounting bolt for
proper tube balance.
Before assembling the rest of the optical tube, you should con-
sider how – or rather, when – you want to mount the optical
tube on the base. You can mount just the lower tube section
on the base – minus the poles and upper tube section – THEN
finish the assembly of the tube with the lower section already
in place on the base. Alternatively, you could complete the
assembly of the optical tube first, then hoist the whole thing
onto the base. You may find it easier to lift the lower tube sec-
tion only and guide it onto its resting place on the base's alti-
tude trunnion than hoisting and mounting the fully assembled
optical tube, especially for the heavier XX14g.
If you want to mount the lower tube section only on the base,
skip to the next section, "Mounting the Optical Tube on the
Dobsonian Base" now. If you want to complete the assem-
bly of the tube before mounting it on the base, continue to
step 6.
6. Now, the upper and lower sections of the tube will be
connected with the four truss pole assemblies. This is a
procedure that will be done whenever the telescope has
been disassembled for transport or storage. It is very
easy to do, and should only take a couple of minutes.
For the XX14g (only), start by installing at least three of
the six counterweights onto the rear cell of the lower tube
section. (The XX12g does not utilize counterweights.)
Installing the counterweights now will make the tube
heavier to lift, but they will ensure that the tube isn't too
front-heavy when mounted onto the base, which could
Lower tube
section
Figure 18
. The clamping knobs on the ends of the truss pole
assemblies thread into the holes in the lower truss support ring on
the lower tube section.
damage components of the optical tube or base if it were
to swing downward rapidly. Three counterweights will be
sufficient; the other three can be installed after the tube is
mounted on the base. To install the counterweights, gen-
tly lay the lower section of the optical tube on its side,
then thread one counterweight onto each of the three
counterweight mounting bolts (Figure 17). Then return
the lower tube section to the vertical position.
7. Now, connect the eight captive clamping knobs on the
ends of the pole assemblies to the lower truss support
ring on the lower optical tube section (Figure 18). This is
done by simply threading the knobs into the holes in the
ring. Do not completely tighten the knobs just yet.
Truss pole
assembly
Clamping
knobs
Lower
truss
support
ring
11