Orion XT4.5 Instruction Manual page 5

Figure 4. Using the two supplied screws, install the aluminum
eyepiece rack in the predrilled holes about halfway down the left
side panel of the base.
You can install the rack so that it can be removed, or you can
install it so it is permanently attached. About halfway down
the left side panel of the base you will notice two predrilled
starter holes, about 4" apart. Take the black wood screws that
come packaged with the rack and thread them into the starter
holes about three turns. Then you can "keyhole" the eyepiece
rack onto the wood screws and continue tightening the
screws. If you want to be able to remove the rack, do not
tighten the screws too tightly. Be certain that the screws are
loose enough that you can lift the rack and remove it from the
screws through the larger part of the hole. If you want to have
the rack permanently attached, attach the screws tightly.
(Figure 4)
Figure 5. Set the optical tube on the
"cradle" of the base so that the altitude
side bearings on the tube rest on the
white plastic "pads." Position the
telescope as shown so that it won't fall
down before the CorrecTension System
is installed and engaged.
Placing the Optical Tube on the Dobsonian Base
Lift the optical tube and set the altitude bearings on either
side of the tube in the "cradle" of the base. The tube will not
yet be properly balanced, since the CorrecTension system
has not been installed. Keep the tube positioned upright, as
shown in Figure 5, for now.
Installing the CorrecTension (XT) Friction
Optimization System
To install the CorrecTension assembly, follow these steps
while referring to Figure 6:
1. Put one of the black nylon spacers on a black Phillips-
head screw. The spacer should be oriented so the narrow
end seats against the head of the screw. Slip one of the
Altitude side
bearing
Spring
Phillips head
screw (black)
Figure 6. Close-up view of the CorrecTension System.
black 1/4" washers over the end of the screw. Now, thread
the screw into the hole in the base side panel just below
the cradle. The screw will thread into the preinstalled insert
in the hole. Use a Phillips screwdriver to tighten the bolt.
Repeat this procedure on the opposite side panel.
2. Next, insert one of the screws with round plastic knob
attached through the end ring of one of the springs. Slip a
black nylon spacer onto the screw. Orient the spacer so
the narrow end is closest to the knob. Thread the entire
assembly into the hole with the brass insert in the tele-
scope's altitude side bearing until tight. The end ring of the
spring should seat onto the narrow end of the spacer.
Repeat this procedure for the other altitude side bearing.
3. Attach a pull loop to the free end of each spring. Slide
the loop through the opening in the ring on the end of
the spring.
4. Now, pull each spring down using the pull loop, and posi-
tion the spring's end ring over the head of the black Phillips
screw (installed in step 1) and onto the narrow part of the
nylon spacer, as shown in Figure 7. You needn't attach
both springs simultaneously; one at a time is fine.
The CorrecTension system is now installed and engaged. If
you wish to remove the telescope tube from the base, you
will first need to disconnect the springs from the "posts" on
the Dobsonian base. Remember to position the tube
upright before doing this, or the tube will fall over. The
springs will remain captive on the altitude side bearings, so
they will not get lost.
Installing the Finder Scope
The SkyQuest XT4.5 comes with a high quality, 6x26 correct-
image achromatic finder scope. (Figure 8a) The "6" means it
magnifies 6 times, the "26" means it has a 26mm effective
diameter lens, and the correct-image means the image in the
finder scope will appear right side up, just like the view
through your naked eye.
Screw w/
round knob
1/4" washer
(black)
Black nylon
Pull loop
spacers
5