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Window
Power
knob
Horizontal
adjustment knob
Figure 15. The red dot scope superimposes an adjustable-
brightness red dot on the sky that shows exactly where the
telescope is pointed.
13. Now, pull each spring down using the pull loop, and
position the spring's end ring over the head of the Phillips
screw (installed in Step 9) and onto the narrow part of the
spring post, as shown in Figure 10D. You needn't attach
both springs simultaneously; one at a time is fine.
14. Now apply the adhesive bumper pad (AA) to the inside
surface of the front brace, right where the bottom end ring
of the optical tube contacts the front brace (when the tube is
rotated just past vertical orientation). (See Figure 11.) Peel
the backing off the bumper pad to expose the adhesive.
The telescope is now mounted on the base and the
CorrecTension spring system is engaged. If you wish to remove
the telescope from the base, you will first need to unhook the
springs from the spring posts on the Dobsonian base. The
springs will remain captive on the altitude side bearings, so
they will not get lost
Installing the Red Dot Scope
To install the red dot scope (V) simply slide its dovetail mount-
ing bracket into the telescope's dovetail base, then tighten
the thumbscrew on the base to secure the mounting bracket
(Figure 12).
Remove the plastic tab sticking out from the battery com-
partment and discard it. This allows the electronic circuit of
the red dot scope to receive power from the installed 3V battery.
Inserting an Eyepiece
The final step in the assembly process is to insert an eyepiece
into the telescope's focuser. Take the cover cap off the end of
the focuser drawtube. To insert the included 1.25" eyepiece (T
or BB1), loosen the thumbscrew on the 1.25" adapter itself (it's
the thumbscrew closest to the eyepiece). Insert the eyepiece
into the adapter and secure it by tightening the thumbscrew
(Figure 13).
8
The assembly of your SkyQuest XT Classic Dobsonian is now
complete. The dust cover (W) on the front of the telescope
should always remain in place when the telescope is not in
use. It is also a good idea to store eyepieces in an eyepiece
LED
case and to replace the cap on the focuser when the telescope
is idle.
3. Using Your Telescope
It is best to get a feel for the basic functions of the SkyQuest
XT Classic Dobsonian during the day, before observing astro-
Vertical
nomical objects at night. This way you will not have to fum-
adjustment
ble around trying to orient yourself in the dark! Find a spot
Battery
knob
outdoors where you have plenty of room to move around the
tray
telescope, and where you have a clear view of some object
or vista that is at least 1/4-mile away. It is not critical that the
base be exactly level, but it should be placed on somewhat
flat ground or pavement to ensure smooth movement of the
telescope.
Remember, never point the telescope at or near the Sun
without using a proper solar filter over the front aperture!
Permanent eye damage could result.
Altitude and Azimuth Motions
The Dobsonian base of the SkyQuest XT Classic permits
motion of the telescope along two axes: altitude (up/down) and
azimuth (left/right) (Figure 14). Simply take hold of the top end
of the tube and move it left or right so the base rotates about
its central azimuth bolt, and move it up or down so the altitude
side bearings rotate in the base's cradle. Both motions can be
made simultaneously and in a continuous manner for easy
aiming. Move the telescope gently—let it glide. In this way you
can point the telescope to any position in the night sky, from
horizon to horizon.
When you're observing an astronomical object, it will drift
across the eyepiece's field of view over time due to the Earth's
rotation. Before it drifts out of the field of view, just grasp the
front of the telescope and give it a gentle pull or nudge to re-
center the object in the eyepiece.
Focusing the Telescope
SkyQuest XT Classic Dobsonians come equipped with a 2"
dual-speed Crayford focuser (Figure 13). The large 2" format
focuser allows use of 2" or 1.25" eyepieces and the Crayford
design prevents imaging shifting while focusing.
To insert a 1.25" eyepiece, first remove the cap from the 1.25"
adapter. Loosen the thumbscrew on the 1.25" adapter, then
insert the eyepiece into the adapter and secure it by tightening
the thumbscrew.
To insert a 2" eyepiece, first loosen the three thumbscrews on
the 2" accessory collar and remove the 1.25" adapter from the
collar. Then insert the 2" eyepiece barrel into the 2" collar all
the way. Retighten the three thumbscrews.
To focus, move the telescope so the front (open) end is point-
ing in the general direction of an object at least 1/4-mile away.
Now, with your fingers, slowly rotate one of the focusing knobs
(see Figure 13) until the object comes into sharp focus. Go a
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