5
2. For observing in the Southern Hemisphere: In the polar scope’s field of
view, locate the four dim stars (~ magnitude 5 - 6) of Octans that conform to
the pattern shown on the reticle. Use the spring loaded elevation adjustment
handle and the two azimuth adjustment knobs on the mount
(Figure 4) to
move those stars into the four small circles labeled “Octans” on the reticle.
3.3 The Orientation of Polaris
Polaris is not located exactly at the North Celestial Pole; it is offset from it by less
than 1 degree. The “Polaris circle” seen in
Figure 3 is a representation of Polaris’
orbit around the NCP. When polar aligning the Sirius Pro mount, you’ll need to
determine where Polaris should be positioned on that circle, relative to the NCP,
for the current time and date. You can use either of the following two methods to
get the orientation:
1. Locate both Polaris and the star Kochab in the sky; Kochab is in the “pan”
of the Little Dipper, while Polaris is at the end of the “handle”. The direction
from Polaris to Kochab can be used as an approximation of the orientation
of Polaris in the polar scope. Put Polaris on the circle on the opposite side of
the NCP from where Kochab is located.
2. At the end of the initialization of the SynScan hand control, after entering
the proper local longitude, latitude, date, time, and Daylight Saving time,
the SynScan hand controller will display the message: “Polaris Position in
P.Scope=HH:MM”. Imagine the graduated circle in
Figure 3 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. Put Polaris in the same orientation on the graduated circle
to finish the polar alignment.
Of the two methods above, the method utilizing the SynScan hand controller is the
more accurate.
3.4 Calibrating the Polar Scope
The polar scope must be calibrated to ensure accurate polar alignment. That
means it has to be precisely aligned with the mount’s R.A., or “polar”, axis. The
following steps outline how to calibrate the polar scope. It’s easiest to do during
daylight hours.
Step 1 - Align Polar Scope’s Optical Axis with the Center of the Reticle
1. Put a distant landmark or object at the center of the reticle in the polar
scope’s FOV using the azimuth adjustment knobs and the elevation
adjustment handle
(Figure 4).
2. Loosen the polar scope lock bolt.
3. Rotate the polar scope 180 degrees, then re-tighten the lock bolt.
(NOTE: you’re rotating the polar scope itself inside its bracket; you’re
not rotating the R.A. axis of the mount until Step 3)
