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POWER LED: The power LED next to the Auto Guide port
serves as a power-on indicator and provides other status infor-
mation:
• Steady on: Power voltage is normal.
• Slow flashing: Power voltage is low; continuing to operate
the mount may damage the battery (if a 12V lead-acid
battery is in use).
• Fast flashing: Power voltage is extremely low; continuing
to operate the mount may damage the battery and the
motor controller in the mount.
8. Polar Alignment
An equatorial mount is designed to compensate for the Earth's
rotation, allowing your telescope to easily "track" the move-
ment of stars and astronomical objects across the sky. Tracking
keeps objects from drifting out of the telescope's field of view
while you're observing or imaging. This is accomplished by the
slow rotation of the mount on its RA axis, using the built-in
RA motor drive. But first the RA axis must be aligned with the
Earth's rotational (polar) axis—a process called polar align-
ment.
The Sirius EQ-G mount comes with a polar axis finder scope
(Figure 9a) housed inside the RA housing of the mount. When
properly aligned and used, it makes accurate polar alignment
quick and easy to do.
If we extend Earth's rotational axis out into space it intersects
an imaginary point called the Celestial Pole. In the northern
hemisphere that point is called the North Celestial Pole, or
NCP. In the southern hemisphere it is the South Celestial Pole,
or SCP. Because the celestial poles are imaginary points, you
can't see them. Fortunately, there are a couple of celestial
"landmarks" close to the poles that help us pinpoint them. In
the northern hemisphere that landmark is Polaris, the North
WARNING: Never look directly at the Sun through
your telescope—even for an instant—without a
professionally made solar filter that completely
covers the front of the instrument, or permanent eye
damage could result. Young children should use this
telescope only with adult supervision.
Star. In the southern hemisphere it is the star Sigma Octantis.
Remove the cover at the rear of the mount's RA housing and
the cap on the front opening of the mount to view through the
polar axis finder scope.
With the telescope tube installed on the mount, turn on the
power to the mount. An internal red LED light will illuminate the
polar scope's reticle (Figure 9b), which should be visible in the
field of view of the polar scope. If the reticle appears blurry, you
can focus it by rotating the polar scope's knurled eyepiece. The
intensity of the illumination can be adjusted using the SynScan
hand controller. The reticle allows accurate polar alignment
from either hemisphere.
6
Power indicator light
Hand
controller
jack
12V DC power
jack
Figure 8. The Sirius EQ-G control panel
For observing in the Northern Hemisphere
1.
Set the mount's latitude to the local latitude (Refer to
"Adjusting the Mount's Latitude and Azimuth" in Section 9)
2.
Find Polaris in the sky. Look north and locate the pattern
of the Big Dipper (Figure 10). The two stars at the end
of the "bowl" of the Big Dipper point right to Polaris. If
you need help determining which direction is north, you
could use your smartphone's compass feature or find a
physical compass to point the way.
3.
Now move the tripod so the mount's RA axis points
roughly in the direction of Polaris.
4.
Loosen the Dec lock lever and rotate the Dec axis until
the hole in the Dec shaft is fully open (Figure 11), which
will allow an unobstructed view of the sky through the
polar scope. Then re-tighten the Dec lock lever.
5.
Make sure that the polar scope is aligned with the RA
Axis. If it is not, follow the procedure in the following
section, "Aligning the Polar Scope" .
6.
Next, rotate the polar scope so that the "0" label on the
reticle pattern is at the 12 o'clock position (i.e., at the top,
as in Figure 9b). When positioned correctly the "3" will be
seen at the right, "6" and the bottom and "9" to the left.
7.
Use the altitude and azimuth adjustments on the mount
to move it incrementally while viewing through the polar
scope, until you can see Polaris in the field of view. It
doesn't matter where it is in the field of view at this point;
you will make fine adjustments to position Polaris where
it needs to be in a moment.
Note: For the azimuth adjustment knobs, turn one clockwise and
the other counterclockwise the same amount, or vice versa. For
altitude adjustment, loosen one altitude adjustment T-bolt before
tightening the other. Over-tightening can damage the bolts.
8.
The circle with fine graduations in the center of the
reticle is for polar alignment in the northern hemisphere.
Find the star Polaris (the brightest star near the North
Celestial Pole, or NCP) in the polar scope; then use the
azimuth and altitude adjustments on the mount to move
Polaris to the proper position in that graduated circle
Autoguider
jack
Power switch
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