Orion SKYQUEST XT10 CLASSIC - Manual (Page 9)

more light-collecting area, or aperture, can yield higher mag-
nifications than a smaller aperture telescope. The maximum
practical magnification for any telescope, regardless of optical
design, is about 60x per inch of aperture. This translates to about
360x for the SkyQuest XT6 and 480x for the XT8.
Keep in mind that as magnification is increased, the brightness
of the object being viewed will decrease; this is an inherent
principle of the physics of optics and cannot be avoided. If
magnification is doubled, an image appears four times dim-
mer. If magnification is tripled, image brightness is reduced by
a factor of nine!
note about High Magnifications:
Maximum magnifications are achieved only under the most
ideal viewing conditions at the best observing sites. Most of the
time, magnifications are limited to 200x or less, regardless of
aperture. This is because the Earth’s atmosphere distorts light
as it passes through. On nights of good “seeing,” the atmo-
sphere will be still and will yield the least amount of distortion.
On nights of poor seeing, the atmosphere will be turbulent,
which means different densities of air are rapidly mixing. This
causes significant distortion of the incoming light, which pre-
vents sharp views at high magnifications.
tube Balance
Dobsonians are designed to balance with standard supplied
accessories, such as an eyepiece and EZ Finder II. But what
if you want to use a larger finder scope or a heavier eyepiece?
The telescope will no longer be properly balanced, and will not
hold its position properly. This makes the telescope difficult to
use, since it is critical that it hold its position (when not pur-
posefully moved) to keep objects centered in the field of vision.
Traditional Dobsonian designs expect the user to compen-
sate for heavier accessories by adding weight to the opposite
end of the telescope tube. Such counterweighting systems
can be expensive and unwieldy. The CorrecTension Friction
Optimization system of the SkyQuest Dobsonians, however,
solves the finicky balance problem. The spring coils pull the
tube down onto the base, thereby increasing the friction on the
altitude bearing pads. With CorrecTension, the added weight
of small front-end loads will not adversely affect the balance of
the telescope.
If you install an array of heavier acces-
sories onto your SkyQuest’s optical tube, you may need at
some point to counterbalance the telescope with a counter-
weight system.
carrying the telescope
Moving the SkyQuest is easy to do. Because the springs of the
CorrecTension system hold the optical tube captive on the base,
the entire telescope can be carried as one unit (6" and 8" models
only). This requires some caution, however. If the telescope is
lifted improperly, the front of the tube could swing down and hit
the ground.
First, point the optical tube straight up (vertical). Remove any
eyepieces from the telescope and optional eyepiece rack, and
place them in an eyepiece case. Grasp the handle on the front
of the base with one hand while supporting the telescope tube
vertically with the other (see Figure 12). Now, lift the telescope
from the handle. Once the telescope is in the horizontal posi-
tion, you can carry the entire unit with one hand. The handle
position properly balances the load for easy carrying.
If you wish to carry the optical tube and base separately, sim-
ply disengage the CorrecTension springs by unhooking them
from the posts on the base, using the pull loops. The springs
remain captive on the telescope side bearings. Now the base
and tube are disengaged and can be transported separately.
Note: The SkyQuest may be too heavy for some users to
lift and carry as one unit. Do not strain yourself! If the load
seems too heavy, disengage the springs and carry the
base and tube separately.
When putting the SkyQuest into a vehicle, common sense pre-
vails. It is especially important that the optical tube does not
knock around; this can cause the optics to become misaligned,
and could dent the tube. We recommend transporting and stor-
ing the tube assembly in a padded case for proper protection.
4. collimation
Collimation is the process of adjusting the mirrors so they are
correctly aligned with one another. Your telescope’s optics
were aligned at the factory, and should not need much adjust-
ment unless the telescope is handled roughly. Accurate mirror
9
Figure 12. Picking up and carrying
the SkyQuest as a single unit (with
tube held captive on the base) requires
some caution.
(a) First, position the tube
vertically. Then, grasp the handle on the
base with one hand while supporting the
tube with the other.
(b) With knees bent,
slowly lift the base while supporting the
tube with one hand. This ensures that
the tube will not swing down and impact
the ground.
(c) As you lift, the whole
assembly will tilt down, becoming nearly
parallel with the ground, at which time you
can let go of the tube with your supporting
hand. Make sure you are comfortable with
the weight of the whole assembly before
attempting to carry it!
a
.
b
. c
.