Using The Equatorial Mount - Orion SkyView Deluxe 9400 Instruction Manual

horizontal when you carefully let go with both hands. This
is the balance point for the Dec. axis. Before clamping the
rings tight again, rotate the telescope so the eyepiece is
at a convenient angle for viewing (this is not possible if
using a 1/4"-20 mounting adapter).
The telescope is now balanced on both axes. Now when you
loosen the lock lever on one or both axes and manually point
the telescope, it should move without resistance and should
not drift from where you point it.
5. Using the Equatorial
Mount
When you look at the night sky, you no doubt have noticed
that the stars appear to move slowly from east to west over
time. That apparent motion is caused by the Earth's rotation
(from west to east). An equatorial mount is designed to com-
pensate for that motion, allowing you to easily "track" the
movement of astronomical objects, thereby keeping them
from drifting out of the telescope's field of view while you're
observing. This is accomplished by slowly rotating the tele-
scope on its right ascension (polar) axis, using only the R.A.
slow-motion cable. But first the R.A. axis of the mount must
be aligned with the Earth's rotational (polar) axis—a process
called polar alignment. Refer to Figure 2 for a close-up look
at the various parts of the SkyView Deluxe Equatorial Mount.
Approximate Polar Alignment
For Northern Hemisphere observers, approximate polar
alignment is achieved by pointing the mount's R.A. axis at the
North Star, or Polaris. It lies within 1° of the north celestial
pole (NCP), which is an extension of the Earth's rotational
axis out into space. Stars in the Northern Hemisphere appear
to revolve around Polaris.
To find Polaris in the sky, look north and locate the pattern of
the Big Dipper (Figure 3). 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 bare-
ly 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. Loosen the latitude lock lever. Turn the latitude adjustment
knob and tilt the mount until the pointer on the latitude
scale is set at the latitude 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. Then retighten the latitude lock lever. The lat-
itude setting 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 opti-
cal tube until it is parallel with the R.A. axis. The pointer
on the Dec. setting circle should read 90°. Retighten the
Dec. lock lever.
4. Lift and rotate the tripod so that the telescope tube (and
R.A. axis) points roughly at Polaris. If you cannot see
Polaris directly from your observing site, consult a compass
and rotate the tripod so that the telescope points North.
The equatorial mount is now polar-aligned for casual observ-
ing. More precise polar alignment is required for
astrophotography.
Polar Aligning Using the Polar Axis Finder
One of the unique features of your new SkyView Deluxe
mount is the polar axis finder scope. It fits conveniently inside
the equatorial mount, and contains a tiny star map that makes
precise polar alignment quick and easy. To use the polar axis
finder scope, follow these instructions:
1. Approximately polar-align the mount as outlined in the
procedure above.
2. Remove the caps that cover the polar finder (one on the
polar finder's eyepiece and one on the equatorial mount).
Focus the polar finder by rotating its eyepiece. Now, sight
Polaris in the polar axis finder scope. If you have followed
the approximate polar alignment procedure accurately,
Polaris will probably be within the field of view. If it is not,
move the tripod left-to-right, and adjust the latitude up and
down until Polaris is somewhere within the field of view of
the polar axis finder scope.
3. Shine a red flashlight down the front end of the polar
finder to illuminate the reticle within the field of view. Make
sure the flashlight shines in at an angle, so as not to block
the polar finder's field of view. It may be helpful to have a
friend hold the flashlight while you look through the polar
finder. Note the constellations Cassiopeia and Ursa Major
(the Big Dipper) in the reticle (ignore the constellation
Octans, as this is provided for Southern Hemisphere
observers). They do not appear to scale, but they indicate
the general positions of Cassiopeia and Ursa Major rela-
tive to Polaris and the north celestial pole (which is
indicated by the cross at the center of the reticle). Next,
the reticle must be rotated so the constellations depicted
match their current orientation in the sky when viewed
with the naked eye. To do this, release the R.A. lock lever
and rotate the main telescope about the R.A. axis until the
reticle is oriented with the sky. You may need to reposition
the telescope about the declination axis so the telescope
does not bump the mount. Once the reticle is correctly ori-
ented, use the R.A. lock lever to secure the main
telescope's position.
4. Now, use the azimuth and latitude adjustment knobs on
the mount to position the star Polaris inside the tiny circle
marked "Polaris" in the polar finder's reticle. You must first
release the latitude lock lever and loosen the bolt that con-
nects the equatorial head to the tripod (underneath the
equatorial mount). Once Polaris is properly positioned
within the reticle, lock the latitude lock lever and retighten
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