Orion ED EQ - Manual (Page 9)

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To find Polaris in the sky, look north and locate the pattern of
the Big Dipper (Figure 9). The two stars at the end of the “bowl”
of the Big Dipper point right to Polaris.
Observers in the Southern Hemisphere aren’t so fortunate to
have a bright star so near the south celestial pole (SCP). The
star Sigma Octantis lies about 1° from the SCP, but it is barely
visible with the naked eye (magnitude 5.5).
For general visual observation, an approximate polar align-
ment is sufficient.
1. Level the equatorial mount by adjusting the length of the
three tripod legs.
2. There are two latitude adjustment L-bolts (see Figure 8);
loosen one while tightening the other. By doing this you will
adjust the latitude of the mount. Continue adjusting the
mount until the pointer on the latitude scale is set at the lati-
tude of your observing site. If you don’t know your latitude,
consult a geographical atlas to find it. For example, if your
latitude is 35° North, set the pointer to 35. The latitude set-
ting should not have to be adjusted again unless you move
to a different viewing location some distance away.
3. Loosen the Dec. lock lever and rotate the telescope’s optical
tube until it is parallel with the right ascension axis, as it is in
Figure 8.
4. Move the tripod so the telescope tube and right ascension
axis point roughly at Polaris. If you cannot see Polaris direct-
ly from your observing site, consult a compass and rotate
the tripod so the telescope points north. There is a label
bearing a large “N” at the base of the equatorial mount
(Figure 10); it should be facing north.
The equatorial mount is now polar aligned for casual observing.
More precise polar alignment is recommended for astropho-
tography. For this we suggest using the optional polar axis
finder scope.
From this point on in your observing session, you should not
make any further adjustments to the latitude of the mount, nor
should you move the tripod. Doing so will undo the polar align-
ment. The telescope should be moved only about its R.A. and
Dec. axes.
Polar alignment using an optional Polar axis
Finder Scope
The SkyView Pro 100mm ED EQ mount can be equipped with
an optional polar axis finder scope (Figure 11a) which goes
inside the right ascension axis of the mount. When properly
aligned and used, it makes accurate polar alignment quick and
easy to do. To install the polar axis finder scope, remove the
cover at the rear of the mount’s right ascension axis (Figure
11b) and thread the polar axis finder scope into the equatorial
mount until tight.
Figure 10. For polar alignment, position the tripod so that the
“N” label at the base of the mount faces north. The azimuth fine
adjustment knobs above it are used to make small adjustments
to the mount’s azimuth position. Be certain to loosen the tripod
attachment knob on the central support shaft before adjusting
these knobs.
Azimuth
adjustment
knobs
Figure 11b. Installing the optional polar axis finder scope.
Big Dipper
(in Ursa Major)
Little Dipper
(in Ursa Minor)
Cassiopeia
N.C.P.
Pointer
Stars
Polaris
Figure 9. To find Polaris in the night sky, look north and find the
Big Dipper. Extend an imaginary line from the two "Pointer Stars"
in the bowl of the Big Dipper. Go about five times the distance
between those stars and you'll reach Polaris, which lies within 1° of
the north celestial pole (NCP).
Figure 11a. The optional polar axis finder scope.
Eyepiece
focus ring
Focus
lock-ring
Objective
lens
Alignment
setscrews (3)