7
the tripod so the telescope points north. There is a label
bearing a large “N” at the top of one tripod leg. It should
be facing north.
The equatorial mount is now polar aligned for casual observing.
More precise polar alignment is recommended for astrophotog-
raphy.
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.
The Polar Axis Finder Scope
The AstroView mount comes with a polar axis finder scope
(Figure 7)
housed inside the right ascension axis of the
mount. When properly aligned and used, it makes accurate
polar alignment quick and easy to do. Remove the caps from
both sides of the AstroView mount’s right ascension axis to
view through the polar axis finder scope.
Alignment of the Polar Axis Finder Scope (during the day)
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 180° about the R.A. axis. It may be
convenient to remove the counterweights and optical tube
before doing this.
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 alignment set-screws on the polar axis finder
(Figure 7)
to redirect the crosshairs of the polar finder
to the apparent center of this circular path. You will
need a 1.5mm hex key (not included) to adjust the three
alignment set-screws.
4. Repeat this procedure until the position that the
crosshairs point to does not rotate off-center when the
mount is rotated in R.A.
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. The above procedure only needs
to be performed once, and it should stay aligned.
Using the Polar Axis Finder Scope
The reticle of the AstroView mount’s polar axis finder scope has
a tiny star map printed on it that makes precise polar alignment
quick and easy. To align the mount using the polar axis finder
scope, follow these instructions:
1. Move the tripod so the telescope tube and right ascension
axis point roughly at Polaris. If you cannot see Polaris
directly from your observing site, consult a compass and
rotate the tripod so the telescope points north.
2. Remove the cap on the front opening of the equatorial
mount. Focus the polar finder by rotating the 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 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. Note the constellation Cassiopeia and the Big Dipper
in the reticle of the polar axis finder scope. 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 the 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 ascension lock
lever to secure the mount’s position.
4. Now use the azimuth adjustment knobs and the latitude
adjustment L-bolts
(Figure 2)
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 SLIGHTLY on the center
support 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.
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.
Note:
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 tri-
pod. Doing so will undo the polar alignment. The tele-
scope 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 simple rota-
tion of 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
the polar axis finder from the mount. Look through the polar
axis finder at a star (at night) or distant object at least 1/4 mile
away (during daylight). Use the eyepiece focus ring to bring
the reticle into sharp focus. Now, use a 1.5mm hex key (not
included) to carefully loosen the three focus lock set-screws
(Figure 7)
by a few turns each and thread the entire objective