Focusing the Telescope
Insert the low-power 25mm eyepiece into the focuser and
secure with the thumbscrew(s). Move the telescope so the
front (open) end is pointing in the general direction of an
object at least 1/4-mile away. Now, with your fingers, slowly
rotate one of the focusing knobs until the object comes into
sharp focus. Go a little bit beyond sharp focus until the image
just starts to blur again, then reverse the rotation of the knob,
just to make sure you’ve hit the exact focus point.
If you have trouble focusing, rotate the focusing knob so the
drawtube is in as far as it will go. Now look through the eye-
piece while slowly rotating the focusing knob in the opposite
direction. You should soon see the point at which focus is
reached.
The focuser of the XT8 features a drawtube lock knob. There
are times when you may want to lock the drawtube to pre-
serve the focus setting. This is done by turning the focus lock
knob clockwise until it is tight. The focus setting will now be
locked. When you need to adjust the focus again, be sure to
loosen the lock knob.
The XT6 does not have a focus lock; instead it has a drawtube
tension thumbscrew. It will not lock the drawtube in place, but
it can be used to increase or decrease the amount of tension
on the drawtube. If you feel the drawtube is moving too loose-
ly when you turn the focusing knob, or if focusing feels too
tight, make adjustments by turning the thumbscrew. Do not
loosen it too much as there must be some tension to keep the
drawtube secure in the focuser.
Aligning the Finder Scope
The finder scope must be aligned accurately with the tele-
scope for proper use. To align it, first aim the main telescope
7
The CorrecTension system is now installed and engaged. If
you wish to remove the telescope from the base, you will first
need to disconnect the springs from the “posts” on the
Dobsonian base. The springs will remain captive on the alti-
tude side bearings, so they will not get lost.
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.
For the XT6: Loosen the two thumbscrews on the eyepiece
holder and insert one of the eyepieces. Then secure it in place
with the thumbscrews. The other eyepiece can be placed in
the eyepiece rack until it is needed.
For the XT8: There are three thumbscrews on the focuser,
one holds the eyepiece, and two hold the 1.25" adapter. To
insert the eyepiece, loosen the thumbscrew that is on the
1.25" adapter itself (it will be highest up on the focuser).
Insert the eyepiece into the adapter and secure it by tighten-
ing the thumbscrew.
The assembly of your SkyQuest Dobsonian is now complete.
It should appear as in Figure 1. The dust cover on the front of
the telescope should always remain in place when the tele-
scope is not in use. It is also a good idea to store eyepieces in
an eyepiece case and to replace the cover 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
Dobsonian during the day, before observing astronomical
objects at night. This way you will not have to fumble around
trying to orient yourself in the dark! Find a spot outdoors
where you have plenty of room to move around the 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!
Altitude and Azimuth
The Dobsonian base of the SkyQuest permits motion of the
telescope along two axes: altitude (up/down) and azimuth
(left/right) (Figure 9). This is very convenient, since up/down
and left/right are the most “natural” ways that people aim. As a
result, pointing the telescope is exceptionally easy.
Simply take hold of the navigation knob 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.
Figure 9.
The SkyQuest has two axes of motion: altitude
(up/down) and azimuth (left/right).
Azimuth
Altitude
