Orion SKYQUEST XT10 - Manual (Page 11)

All three SkyQuest IntelliScope Dobsonian models have a
focal length of 1200mm. So, the magnification with the sup-
plied 25mm eyepiece is:
1200 mm
= 48x
25 mm
The magnification provided by the 10mm eyepiece is:
1200 mm
= 120x
10 mm
The maximum attainable magnification for a telescope is
directly related to how much light its optics can collect. A tele-
scope with more light-collecting area, or aperture, can yield
higher magnifications than a smaller-aperture telescope. The
maximum practical magnification for any telescope, regard-
less of optical design, is about 60x per inch of aperture. This
translates to about 360x for the SkyQuest XT6, 480x for the
XT8, and 600x for the XT10. Of course, such magnifications
will only yield reasonable images if atmospheric conditions
are favorable.
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!
use of 2-inch Eyepieces (Xt8 and Xt10 only)
All SkyQuest telescopes are designed to accept eyepieces
with a barrel diameter of 1.25". The XT8 and XT10 have 2"
focusers that accept both 1.25" and optional 2" eyepieces.
At low magnifications, 2" eyepieces can provide a wider field
of view than standard 1.25" eyepieces. A wider field can be
desirable for viewing extended deep-sky objects that are too
large to fit within a narrower field of view.
To use 2" eyepieces, simply loosen the two large thumbscrews
on the 2" adapter that are just in front of the thumbscrew that
holds the provided 1.25" adapter in place (Figure 13a). Once
these thumbscrews are loosened the adapter comes off,
exposing the 2" diameter focuser drawtube Now, insert your
2" eyepiece into the drawtube and secure with the two thumb-
screws loosened previously, and you’re ready to observe.
tube Balance
SkyQuest IntelliScope Dobsonians are designed to balance
with standard supplied accessories, such as an eyepiece
and a finder scope. But what if you want to use a larger finder
scope or a heavier eyepiece? Traditional Dobsonian designs
require the user to compensate by adding weight to the oppo-
site end of the telescope tube. Such counterweighting systems
can be expensive and unwieldy. The CorrecTension system of
the SkyQuest IntelliScope Dobsonians, however, solves the
finicky balance problem. The brake pads press against the
altitude bearings on the optical tube and increase the friction.
With CorrecTension, the added weight of front-end loads will
not adversely affect the balance of the telescope. Simply tight-
en the tensioning knob to balance any extra load.
Carrying the telescope
Transporting the SkyQuest is easy to do. The tube uncouples
from the base and each component can be carried separately.
The base has a handle for easy carrying. With the retaining
and tensioning knobs of the CorrecTension(XT) system hold-
ing the optical tube captive on the base, the entire telescope
can be carried as one unit. (This is not practical for the XT10
due to its hefty weight and size.) This requires some caution,
however. If the telescope is lifted improperly, the tube could
swing down and hit the ground.
First, point the optical tube straight up (vertical). Remove any
eyepieces from the telescope and eyepiece rack, and place
them in an eyepiece case. Grasp the handle on the front of
11
Figure 17. Picking up and
carrying the SkyQuest IntelliScope
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.
This ensures that the tube will not
swing down and impact the ground
(b) With knees bent, slowly lift the
base while supporting the tube.
(c) As you lift, continue to support
the tube with one hand to keep it
parallel with the ground. Make sure
you are comfortable with the weight
of the whole assembly before
attempting the carry it!
a.
b. c.