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Figure 9b is a representation of Polaris' orbit around the NCP.
When polar aligning the Sirius mount, you'll need to determine
where Polaris should be positioned around that circle, relative
to the NCP, for the current time and date. That information is
found during initialization of the SynScan hand controller at
startup. 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 9b as a clock's face
with 12:00 at the top, and the current time pointing to the
"HH:MM" . The orientation of the hour hand (HH) of the clock
represents the orientation of Polaris in the polar scope. Put
Polaris in exactly the same orientation on the graduated circle
to finish the polar alignment.
Polaris' position relative to the NCP changes slightly over the
course of years. The polar scope reticle displays three circles
to represent Polaris's "orbit" around the NCP in the year 2012,
2020, and 2028. There are also tiny hash marks at the 0, 3,
6, and 9 o'clock positions representing the years 2016, 2024,
and 2032. Refer to the "key" to the right of the Polaris circle.
When polar aligning in the Northern Hemisphere, you should
place Polaris on the correct circle (or gap between them) cor-
responding to the present year.
Aligning the Polar Scope
Before using the polar scope for polar alignment, it must be
aligned to the mount's RA axis. At the center of the reticle is
a cross, which you'll use in the procedure below to align the
polar scope.
1.
Loosen the Dec lock lever and rotate the optical tube
about the Dec axis until you have a clear view through
the polar axis finder scope. Then retighten the Dec lock.
2.
Look through the polar scope at a distant object (during
the day) or at Polaris (at night, in Northern Hemisphere)
and center it on the cross in the middle of the reticle. You
may need to turn the latitude adjustment lever and the
azimuth adjustment knobs of the mount and even move
the tripod itself to do this.
3.
Rotate the mount 180° about the RA axis. It may
be convenient to remove the optical tube and
counterweight(s) before doing this. If the object remains
centered on the cross after the rotation, then the
polar scope is properly aligned to the RA axis and no
adjustment is needed.
4.
If the target deviated from the cross, then use the 1.5mm
Allen wrench to adjust the three small Allen screws on
the polar scope (Figure 9a) to move the target half the
distance back to the cross (Figure 9c). Then you will
re-center the object on the cross as in Step 2 using
the mount's azimuth adjustment knobs and the latitude
adjustment lever (without moving the tripod this time).
5.
Repeat Steps 2 to 4 until the object stays centered on the
cross of the reticle when rotating the mount on the RA axis.
NOTE:
• When adjusting the Allen screws, first loosen one screw
only ¼ of a turn, and then tighten the other two.
8
• Do not over tighten the Allen screws as it might damage
the reticle plate in the polar scope.
• Do not loosen one screw completely or loosen more than
one screw at a time, or the reticle plate in the polar scope
will be disengaged and further adjustment is impossible.
• If the reticle plate does disengage, remove the polar
scope's eyepiece by turning it counterclockwise and
engage the reticle plate again.
9. Operating the Sirius EQ-G
Moving the Mount Manually
The Sirius EQ-G mount can be moved manually in RA (east-
west) or Dec (north-south) or can be moved electronically with
the SynScan hand controller. However, after an initial GoTo star
alignment, moving the mount manually will void the star align-
ment, which will have to be performed again. After GoTo star
alignment, move the telescope only electronically using the
SynScan hand controller, to preserve the alignment!
If moving the mount manually is desired, loosen one or both
of the lock levers on the RA and Dec axes to rotate the mount.
Both levers should be tightened for electronic operation of the
mount via the SynScan hand controller.
Locating Objects Using the Setting Circles
With a computerized GoTo mount like the Sirius EQ-G, you do
not need setting circles to locate objects. The SynScan com-
puterized object locator will do that for you! But should you
wish to find objects "the old fashioned way," or need to locate
an object that is not in the SynScan database based on its
celestial coordinates, you can use the RA and Dec setting cir-
cles to pinpoint the desired object (Figure 12).
First, you will need to calibrate the setting circles. Do this by
simply pointing the telescope at a celestial object with known
RA and Dec coordinates, which you can look up in a star atlas
or on the internet. Then loosen the locking thumbscrew on
each setting circle and turn the setting circles so the values
for RA and Dec line up with the indicator arrow next to each
setting circle. Then re-tighten the setting circle locking thumb-
screws.
For the RA setting circle, note that there are two sets of num-
bers below the hash marks. The lower set of numbers applies
to viewing in the Northern Hemisphere, while the numbers
above them apply to viewing in the Southern Hemisphere.
The Dec setting circle scale features four quadrants from 0 to
90-degrees each. Users should use the proper quadrant when
calibrating the Dec setting circle.
Adjusting the Mount's Latitude and Azimuth
Setting the RA axis to the correct latitude is necessary for
accurate polar alignment and tracking. Refer to the latitude
scale while cranking the latitude adjustment bolt to achieve the
proper tilt. Loosen one of the two bolts (first) while tightening
the other. The latitude should be set to the same latitude at
which you are located.
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