Orion SKYQUEST XX12 - Manual (Page 8)

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7. Insert the modular jack on the azimuth encoder board
(E) into the square-shaped hole in the top baseplate (D)
and align the encoder board so the screw lines up with
the pre-drilled pilot hole in the baseplate, and the large
hole in the encoder board lines up with the central hole in
the baseplate (Figure 6). Thread the encoder wood screw
(with spacer washers attached) into the pre-drilled pilot
hole with a Phillips screwdriver and tighten until just tight.
Note: After the azimuth encoder board is installed to the bot-
tom of the top baseplate, do not rest the baseplate on the
ground, or the encoder board could be damaged. At this
stage, rest the partially assembled base on its side.
8. Position the ground baseplate (A) so that it is standing on
its plastic feet. Place one fender washer (H) onto the azi-
muth axis screw (I), then insert the screw up through the
hole in the ground baseplate.
9. Place the encoder disk (J), flat side down, over the azi-
muth axis screw (I) and onto the ground baseplate (A).
The encoder disk is found in the box with the optical tube
assembly.
10. Place the brass azimuth bushing (F) onto the azimuth axis
screw (I) so the wide end of the bushing is closest to the
encoder disk (J). Seat the bushing onto the encoder disk
so the registration feature on the bushing goes into the
hole in the encoder disk.
11. Carefully position the top baseplate (D) over the ground
baseplate (A) and lower it so the brass azimuth bushing (F)
goes through the center hole in the top baseplate (Figure
7). When the top baseplate is resting on the ground base-
plate, the brass bushing should extend just above the top
surface of the top baseplate.
12. Place the remaining fender washer (K) onto the shaft of
the azimuth axis screw (I), then thread the hex lock nut
(L) onto the end of the azimuth axis screw and tighten it
finger tight, for now.
13. To tighten the hex lock nut (L) onto the azimuth axis screw
(I), tilt the assembled Dobsonian base at a slight angle
to lift the ground baseplate off the ground. Now, with one
wrench (or pliers) hold the head of the azimuth axis screw
still while turning the hex lock nut with the other wrench.
Figure 8 shows this being done. Tighten the hex lock nut
just until the top fender washer is no longer moving freely,
then tighten the hex nut 3/16 to 1/4 turn beyond that. This
provides the proper spacing between the encoder disk
and the azimuth encoder board.
14. Two altitude bearing cylinders (R) connect to the interior
surface of each side panel. Line up one of the altitude
bearing cylinders with one of the two through holes in
each side panel. The beveled end of the cylinder should be
facing away from the side panel. Push a bearing cylinder
screw through the side panel and thread it into the built-in
nut in the cylinder with the included 4mm hex key (Figure
9). Repeat this for the remaining three bearing cylinders.
15. Attach the encoder connector board to the interior surface
of the left side panel. The encoder connector board can
be found in the box with the optical tube. Place the board
against the left panel so that the modular jack fits into
the square-shaped hole and using a Phillips screwdriver,
thread four encoder wood screws through the connector
Figure 7. Lower the top baseplate onto the bottom baseplate.
The brass bushing should pass through the center hole in the top
baseplate (and the large hole in the azimuth encoder board).
Azimuth
encoder board
Brass azimuth
bushing Encoder
disc
Ground baseplate
Top baseplate
Figure 8. To connect the baseplates, tilt them only slightly, as
shown. Do not place them on their side. (a) Use one wrench (or
pliers) to hold the hex nut steady (b) while turning the hex head of
the azimuth axis screw with another wrench.
b.
a.