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a.
b.
Figure 23. a) The polar axis scope has three alignment setscrews
located near the eyepiece. b) After centering a distant target and
rotating the mount 180 degrees in R.A., adjust the three alignment
setscrews to move the target half the distance back to the center
cross. Then use the mount's latitude jackscrew and azimuth
adjustment knobs to recenter the target.
4.
Turn on the power to the mount to illuminate the polar
scope. The reticle pattern (Figure 21) should now be
visible in the polar scope. If the image appears blurred,
rotate the polar scope's knurled eyepiece to focus it.
Note: The red illumination of the polar scope reticle is adjust-
able from 100% to 0% brightness. The default illumination is
100%, which may be too bright for readily seeing Polaris and
surrounding stars. To reduce the brightness, access the menu
"UTILITY \ Polar Scope LED" and press the ENTER key. Use
the Left direction key to reduce the illumination to the desired
level (probably 10% or less), then press the ENTER key to
set it.
Alignment
setscrews
(x3)
If Polaris (or daytime
target) drifted to here
Place Polaris (or
daytime target) here
(half the distance)
5.
Now, sight Polaris in the polar axis finder scope. If it's not
in the field of view, move the mount left or right using the
azimuth adjustment knobs, and adjust the altitude up or
down using the jackscrew until Polaris is visible in the
polar scope.
6.
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 NCP in the sky. Rotate the reticle so the
star patterns depicted match their current orientation
in the sky when viewed with the naked eye. To do this,
release the R.A. clutch 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 during this procedure.
7.
Now use the azimuth adjustment knobs and the latitude
jackscrew on the mount to position Polaris inside the tiny
circle on the finder's reticle. You must first loosen – only
very slightly! – the knob underneath the mount head 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 under the mount and lightly tighten the altitude lock
knobs on the sides of the mount.
Polar Alignment in Southern Hemisphere: In the field of
view of the polar scope, locate the four dim stars that form
the pattern labeled "Octans," which lie near the South Celestial
Pole. Loosen the R.A. clutch and rotate the R.A. axis to align
the orientation of the "Octans" graphic to the same four stars
in the actual sky. Then use the altitude jackscrew and the azi-
muth adjustment knobs to move the four stars into the four
small circles of the Octans graphic on the reticle. With that, the
mount is now polar aligned for Southern Hemisphere viewing.
4.5
Another Way to Determine Position of
Polaris on Reticle
At the end of the initialization of the SynScan hand controller,
after entering the proper local longitude, latitude, date, time,
and daylight-saving time setting, the SynScan hand controller
will display the message: "Polaris Position in P.Scope=HH:MM" .
Imagine the larger circle in Figure 21 as a clock's face with
12:00 at the top, with the current time pointing to the "HH:MM" .
The orientation of the hour hand of the clock represents the
orientation of Polaris in the polar scope. Place Polaris at the
same orientation on the reticle's large circle to finish the polar
alignment.
Note: From this point on in your observing or imaging 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 disrupt the polar alignment. The telescope should
be moved only about its right ascension and declination axes.
13
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