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lations in the night sky, you will need to get a planisphere to
identify them.
Start by choosing bright objects to view. The brightness of an
object is measured by its visual magnitude; the brighter an
object, the lower its magnitude. Choose an object with a visu-
al magnitude of 9 or lower. Many beginners start with the
Messier objects, which represent some of the best and bright-
est deep-sky objects, first catalogued about 200 years ago by
the French astronomer Charles Messier.
Determine in which constellation the object lies. Now, find the
constellation in the sky. If you do not recognize the constella-
tions on sight, consult a planisphere. The planisphere gives
an all-sky view and shows which constellations are visible on
a given night at a given time.
Now, look at your star chart and find the brightest star in the
constellation that is near the object you are trying to find.
Using the finder scope, point the telescope at this star and
center it on the crosshairs. Next, look again at the star chart
and find another suitably bright star near the bright star cur-
rently centered in the finder. Keep in mind that the field of
view of the finder scope is approximately 5°, so you should
choose another star that is no more that 5° from the first star,
if possible. Move the telescope slightly, until the telescope is
centered on the new star.
Continue using stars as guideposts in this way until you are
at the approximate position of the object you are trying to find
(Figure 20). Look in the telescope’s eyepiece, and the object
should be somewhere within the field of view. If it’s not, sweep
the telescope carefully around the immediate vicinity until the
object is found.
If you have trouble finding the object, start the starhop again
from the brightest star near the object you wish to view. This
time, be sure the stars indicated on the star chart are in fact
the stars you are centering in the eyepiece. Remember, the
finder scope (and main telescope eyepiece, for that matter)
gives an inverted image, so you must keep this in mind when
starhopping from star to star.
Note About Astrophotography
SkyQuest XT10 Dobsonians are designed for visual, not pho-
tographic use. The Dobsonian mount is not an equatorial-type
mount, so it cannot be motor driven for long exposure
astrophotography. SkyQuests have also been optically opti-
mized 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. With the use of afocal
photography techniques (where the camera is simply placed
to the eyepiece to take a picture) and digital cameras, it is
possible to take pictures of bright objects. Certain photo-
graphic aids, such as the Orion SteadyPix, can help in taking
photos by the afocal method.
6. Care and Maintenance
If you give your telescope reasonable care, it will last a life-
time. Store it in a clean, dry, dust-free place, safe from rapid
changes in temperature and humidity. Do not store the tele-
scope outdoors, although storage in a garage or shed is OK.
Small components like eyepieces and other accessories
should be kept in a protective box or storage case. Keep the
cap on the front of the telescope when it is not in use.
The telescope requires very little mechanical maintenance.
The optical tube is steel and has a smooth painted finish that
is fairly scratch-resistant. If a scratch does appear on the
tube, it will not harm the telescope. Smudges on the tube can
be wiped off with a soft cloth and a household cleaner such
as Windex or Formula 409.
Cleaning Lenses
Any quality optical lens cleaning tissue and optical lens clean-
ing fluid specifically designed for multi-coated optics can be
used to clean the exposed lenses of your eyepieces or finder
scope. Never use regular glass cleaner or cleaning fluid
designed for eyeglasses. Before cleaning with fluid and tis-
sue, however, blow any loose particles off the lens with a
blower bulb or compressed air. Then apply some cleaning
fluid to a tissue, never directly on the optics. Wipe the lens
gently in a circular motion, then remove any excess fluid with
a fresh lens tissue. Oily fingerprints and smudges may be
removed using this method. Use caution; rubbing too hard
may scratch the lens. On larger lenses, clean only a small
area at a time, using a fresh lens tissue on each area. Never
reuse tissues.
Figure 20.
Starhopping is a good way to locate hard-to-find
objects. Refer to a star chart to map a route to the object that uses
bright stars as guideposts. Center the first star you’ve chosen in the
finder scope and telescope eyepiece (1). Now move the scope
carefully in the direction of the next bright star (2), until it is
centered. Repeat (3 and 4). The last hop (5) should place the
desired object in the eyepiece.
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