Orion XT12 - Manual (Page 18)

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the sky, excluding the Sun and the Moon. It is so bright that
sometimes it is visible to the naked eye during full daylight!
Ironically, Venus appears as a thin crescent, not a full disk,
when at its peak brightness. Because it is so close to the Sun,
it never wanders too far from the morning or evening horizon.
No surface markings can be seen on Venus, which is always
shrouded in dense clouds.
MARS The Red Planet makes a close approach to Earth
every two years. Observing Mars is most favorable at these
times. You should see a salmon-colored disk with some dis-
tinct dark patches, and you may be able to spot a whitish
polar ice cap. To see surface detail on Mars, you will need a
high power eyepiece and very steady air!
D. The Stars
Stars will appear as tiny points of light. Even powerful tele-
scopes cannot magnify stars to appear as anything more than
pinpoints. You can, however, enjoy the different colors of the
stars and locate many pretty double and multiple stars. The
famous “Double-Double” in the constellation Lyra and the gor-
geous two-color double star Albireo in Cygnus are favorites.
Defocusing a star slightly can help bring out its color.
E. Deep-Sky Objects
Under dark skies, you can observe a wealth of fascinating
deep-sky objects; that is, objects that reside outside of our
solar system. These include gaseous nebulas, open and
globular star clusters, and a variety of different types of galax-
ies. The large aperture of the SkyQuest XT12 IntelliScope is
particularly well suited to gathering light, which is critical for
observing these usually faint celestial entities. For deep-sky
observing it is important that you find an observing site well
away from light pollution. Take plenty of time to let your eyes
adjust to the darkness. As you become more experienced
and your observing skills get sharper, you will be able to ferret
out more and more subtle details and structure from these
fascinating objects.
Beginners are often surprised to discover that the deep-
sky objects they see through the eyepiece of a telescope
are mostly grayish, not colorful like those you see in long-
exposure photographs. The reason is that our eyes are not
sensitive to color in faint light. Still, there is something very
special about seeing an astronomical object in real time with
your own eyes — “live,” if not in living color.
Note About Astrophotography
The SkyQuest XT12 IntelliScope is designed for visual, not
photographic use. The Dobsonian mount is not an equatorial-
type mount, so it cannot be motor driven for long exposure
astrophotography. The telescope has also been optically
optimized for visual use, since photographic optimization
degrades visual performance.
With that in mind, however, it is possible to do some simple
astrophotography with a SkyQuest XT12 IntelliScope. With
the use of afocal photography techniques (where the camera
is simply put right up to the eyepiece to take a picture) and
digital cameras, it is possible to take pictures of bright objects.
Certain photograph aids, such as the Orion SteadyPix, can
help in taking photos by the afocal method.
6. Optional IntelliScope
Computerized Object
Locator
Perhaps the most exciting feature of the SkyQuest XT12
IntelliScope is its compatibility with the optional IntelliScope
Computerized Object Locator (controller). When plugged into
the IntelliScope port on the telescope’s base, the IntelliScope
controller enables the user to point the telescope quickly and
effortlessly to more than 14,000 celestial objects with the push
of a button. After a simple two-star alignment procedure, you
just select an object to view from the intuitive keypad, then
read the guide arrows on the controller’s illuminated liquid
crystal display and move the telescope in the corresponding
direction. In seconds, the object will be waiting in the tele-
scope’s field of view, ready to observe. It’s that simple!
Even without the optional IntelliScope controller, the SkyQuest
XT12 IntelliScope provides a tremendous observing experi-
ence. But addition of the controller provides a whole new level
of convenience and capability, as you’re able to locate and
view more objects in an evening that you ever could before.
The IntelliScope controller works by communicating elec-
tronically with a pair of high-resolution, 9,216-step digital
encoders, one of which will reside on one of the telescope’s
side bearings (this encoder is included with the optional
IntelliScope controller), the other of which you installed dur-
ing assembly of the base. The encoders allow highly precise
positioning of the telescope to coordinates programmed into
the IntelliScope controller’s database for each object. Since
the telescope is not dependent on motors for movement, you
can point the telescope at your target much more quickly (and
quietly!) than other computerized telescopes can — and with-
out guzzling all those batteries in the process.
The IntelliScope database includes:
• 7,840 objects from the Revised New General Catalog
• 5,386 objects from the Index Catalog
• 110 objects from the Messier Catalog
• 837 selected stars (mostly double, multiple, and variable
stars)
• 8 planets
• 99 user-programmable objects
With the user-friendly IntelliScope controller, there are
many ways to locate an object. If you know its catalog num-
ber (NGC or Messier number, for instance), you can enter
it using the illuminated keypad buttons. Or you can press
one of the object-category buttons (Cluster, Nebula, Galaxy,
etc.) to access a list of objects by type. For a tour of the best
objects visible in a given month, you just press the Tour but-
ton. Another great feature of the IntelliScope is the ability to
identify an “unknown” object in the field of view — just press