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4. Loosen the azimuth adjustment knob and rotate the entire
equatorial mount left-to-right so the telescope tube (and
R.A. axis) points roughly at Polaris. If you cannot see
Polaris directly from your observing site, consult a com-
pass and rotate the equatorial mount so the telescope
points North. Retighten the azimuth adjustment knob.
The equatorial mount is now approximately polar-aligned for
casual observing. More precise polar alignment is required for
astrophotography. Several methods exist and are described
in many amateur astronomy reference books and astronomy
magazines.
From this point on in your observing session, you should not
make any further adjustments to 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 R.A. and Dec. axes.
Use of the R.A. and Dec. Slow-Motion Control Cables
The R.A. and Dec. slow-motion control cables allow fine
adjustment of the telescope's position to center objects within
the field of view. Before you can use the cables, you must
manually "slew" the mount to point the telescope in the vicin-
ity of the desired target. Do this by loosening the R.A. and
Dec. lock thumb screws and moving the telescope about the
mount's R.A. and Dec. axes. Once the telescope is pointed
somewhere close to the object to be viewed, retighten the
mount's R.A. and Dec. lock thumb screws.
The object should now be visible somewhere in the tele-
scope's (aligned) finder scope. If it isn't, use the slow-motion
Big Dipper
(in Ursa Major)
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 5 times the distance between those stars and you'll reach Polaris, which lies within 1° of the north celestial pole
(NCP).
Figure 4. Finding Polaris
controls to scan the surrounding area of sky. If the object is
still not visible in the finder scope, you will need to slew the
mount again, this time being more careful to point the tele-
scope closer to what you wish to view.
When the object is visible in the finder scope, use the slow-
motion controls to center it. Now, look in the telescope with a
long focal length (low magnification) eyepiece. If the finder
scope is properly aligned, the object should be visible some-
where in the field of view. If it is not, you may need to realign the
telescope's finder scope.
Once the object is visible in the telescope's eyepiece, use the
slow-motion controls to center it in the field of view. You can
now switch to a higher magnification eyepiece, if you wish.
After switching eyepieces, you can use the slow-motion con-
trol cables to re-center the image, if necessary.
Little Dipper
(in Ursa Minor)
N.C.P.
Polaris
Cassiopeia
7
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