Celestron CGEM DX, Инструкция по эксплуатации

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the celestial pole, you can simply point the polar axis of your
telescope at Polaris . Although this is by no means perfect
alignment, it does get you within one degree and is suitable for
visual observing and short exposure piggyback photography .
This must be done in the dark when Polaris is visible and can
be done using the hole in the polar axis or with the help of
the optional polar axis finderscope . See Optional
Accessory section .
1 . Set the telescope up so that the polar axis is pointing
towards north (see figure 4-4) .
2 . Remove the polar finderscope cover and the polar axis cover
from both sides of the mount . The polar finderscope cover
unthreads from the rear of the mount and the polar axis
cover simply press fits into the front of the mount . See
figure 4-4 .
3 . Loosen the DEC clutch knob and move the telescope so
that the tube is perpendicular to the polar axis, ie, the tube
should be pointing either due west or east .
4 . Look through the hole located underneath the polar
finderscope cover (or through the eyepiece if using the
optional polar axis finderscope) . You should be able to see
the sky from the hole under the polar axis cover .
5 . Adjust the mount in altitude and/or azimuth until Polaris
is visible through the polar axis hole . Center Polaris as
accurately as possible .
Like the previous method, this gets you close to the pole but
not directly on it . For help in identifying and locating Polaris,
read the section below .
F
inDinG thE
n
orth
C
ElEStial
p
olE
In each hemisphere, there is a point in the sky around which
all the other stars appear to rotate . These points are called the
celestial poles and are named for the hemisphere in which they
reside . For example, in the northern hemisphere all stars move
around the north celestial pole . When the telescope’s polar
axis is pointed at the celestial pole, it is parallel to the Earth’s
rotational axis .
Many methods of polar alignment require that you know how
to find the celestial pole by identifying stars in the area . For
those in the northern hemisphere, finding the celestial pole is
not too difficult . Fortunately, we have a naked eye star less than
a degree away . This star, Polaris, is the end star in the handle
of the Little Dipper . Since the Little Dipper (technically called
Ursa Minor) is not one of the brightest constellations in the
sky, it may be difficult to locate from urban areas . If this is the
case, use the two end stars in the bowl of the Big Dipper (the
pointer stars) . Draw an imaginary line through them toward the
Little Dipper . They point to Polaris (see Figure 4-5) . The position
of the Big Dipper changes during the year and throughout
the course of the night . When the Big Dipper is low in the sky
(i .e ., near the horizon), it may be difficult to locate . During
these times, look for Cassiopeia (see Figure 4-5) . Observers in
the southern hemisphere are not as fortunate as those in the
northern hemisphere . The stars around the south celestial pole
are not nearly as bright as those around the north . The closest
star that is relatively bright is Sigma Octantis . This star is just
within naked eye limit (magnitude 4 .5) and lies about 59 arc
minutes from the pole .
The north celestial pole is the point in the northern
hemisphere around which all stars appear to rotate. The
counterpart in the southern hemisphere is referred to as
the south celestial pole.
F
igure
4-4
Polar Axis
Cover
Points
towar
ds North
Polar
Finderscope
Cover
Polaris
(North Star)
Big Dipper
Little Dipper
Cassiopeia
N.C.P.
Poin
ter S
tars
F
igure
4-5
t
he two stars in the Front oF the bowl oF the
b
ig
D
iPPer Point
to
P
olaris whiCh is less than one Degree FroM the true
(
north
)
Celestial Pole
. C
assioPeia
,
the
“w”
shaPeD Constellation
,
is on
the oPPosite siDe oF the Pole FroM the
b
ig
D
iPPer
. t
he
n
orth
C
elestial
P
ole
(n.C.P.)
is MarkeD by the
“+”
sign
.