Orion SKYVIEW PRO 120 EQ Instruction Manual page 9

Eyepiece Alignment
focus ring set-screws (3)
Figure 9a.
The optional polar axis finder scope.
directly 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 8). It should be facing north.
The equatorial mount is now polar aligned for casual observ-
ing. More precise polar alignment is recommended for astro-
photography. 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 120 EQ mount can be equipped with an
optional polar axis finder scope (Figure 9a) 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 9b) and thread
the polar axis finder scope into the equatorial mount until tight.
Alignment of the Polar Axis Finder Scope
1. Look through the polar finder at a distant object (during the
day) and center it in the crosshairs. You may need to adjust
the latitude adjustment L-bolts and the tripod position to do
this.
2. Rotate the mount 180º about the R.A. axis. Again, it may
be convenient to remove the counterweights and optical
tube first.
3. Look through the polar finder again. Is the object being
viewed still centered on the crosshairs? If it is, then no fur-
ther adjustment is necessary. If not, then look through the
polar finder while rotating the mount about the R.A. axis.
You will notice that the object you have previously centered
moves in a circular path. Use the three alignment set-
screws on the polar axis finder to redirect the crosshairs of
the polar finder to the apparent center of this circular path.
Objective
lens
Focus
lock ring
Figure 9b.
Installing the optional polar axis finder scope.
Figure 10.
The optical tube must be at a 90° angle to the right
ascension axis in order to view through the polar axis finder.
Repeat this procedure until the position that the crosshairs
point to does not rotate off-center when the mount is rotat-
ed in R.A. Once this is accomplished, retighten the thumb-
screws.
The polar axis finder scope is now ready to be used. When
not in use, replace the plastic protective cover to prevent the
polar finder from getting bumped, which could knock it out of
alignment.
Using the Polar Axis Finder Scope
The reticle of the polar axis finder scope for the SkyView Pro
has a tiny star map printed on it that makes precise polar
alignment quick and easy. If you do not have a clear view of
Polaris from your observing site, you will not be able to use
the polar axis finder to precisely polar align the telescope. To
align the mount using the polar axis finder scope, follow these
instructions:
1. Approximately polar align the mount as outlined in the pro-
cedure above.
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