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a
less of aperture. This is because the Earth's atmosphere
distorts light as it passes through. On nights of good "seeing,"
the atmosphere 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 prevents 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 compensate
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 accessories onto your
SkyQuest's optical tube, you may need at some point to coun-
terbalance the telescope with a counterweight system.
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b
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c
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 11). 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
prevails. It is especially important that the optical tube does
not knock around; this can cause the optics to become mis-
aligned, and could dent the tube. We recommend transporting
and storing the tube assembly in a padded case for proper
protection.
Figure 11.
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!
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