Orion ED EQ - Manual (Page 10)

10
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 posi-
tion to do this.
2. Rotate the mount 180° 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
further 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 align-
ment setscrews on the polar axis finder to redirect the
crosshairs of the polar finder to the apparent center of this
circular path.
4. Repeat this procedure until the position that the cross-
hairs point to does not rotate off-center when the mount
is rotated in R.A. Once this is accomplished, retighten the
thumbscrews.
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.
2. Loosen the Dec. lock lever and rotate the optical tube
on the declination axis so that the tube is at a 90° to the
right ascension axis (Figure 12). This is so you can view
through the mount with the polar axis finder. Tighten the
Dec. lock lever.
3. Remove the cap on the front of the equatorial mount (Figure
8), and focus the polar finder by rotating the eyepiece.
4. 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 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.
5. 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 constellation Cassiopeia and the Big Dipper in
the reticle. They do not appear in scale, but they indicate
the general positions of Cassiopeia and the Big Dipper
relative to the north celestial pole (which is indicated by
the cross at the center of the reticle). Rotate the reticle so
the constellations depicted match their current orientation
in they sky when viewed with the naked eye. To do this,
release the R.A. lock lever and rotate the main telescope
around the R.A. axis until the reticle is oriented with sky.
For larger optical tubes, you may need to remove the tube
from the mount to prevent it from bumping into the mount.
Once the reticle is correctly oriented, use the right ascen-
sion lock lever to secure the mount’s position.
6. Now use the azimuth adjustment knobs (Figure 10) and
the latitude adjustment L-bolts (Figure 8) on the mount
to position the star Polaris inside the tiny circle marked
“Polaris” on the finder’s reticle. You must first loosen the
knob underneath the equatorial mount on the center sup-
port shaft to use the azimuth adjustment knobs. Once
Polaris is properly positioned within the reticle, you are
precisely polar aligned. Retighten the knob underneath
the equatorial mount
From this point on in your observing session, you should not
make any further adjustments in the azimuth or the latitude
of the mount, nor should you move the tripod. Doing so will
undo the polar alignment. The telescope should be moved
only about its right ascension and declination axes.
additional note regarding Focusing the Polar
axis Finder Scope
The polar axis finder scope is normally focused by simply
rotating the eyepiece focus ring. However, if after adjusting
the focus ring you find that the image of the reticle is sharp,
but the stars are out of focus, then you must adjust the focus
of the polar axis finder’s objective lens. To do this, first remove
Figure 12. The optical tube must be at a 90° angle to the right
ascension axis in order to view through the polar axis finder.