8
desired location. Both the R.A. and Dec. clutches should be
tightened when driving the mount with the internal motors.
3.2 using the setting circles
As indicated in
Figure 13, the Sirius Pro features right ascen-
sion and declination setting circles. Most users of a GoTo tele-
scope will not have a need to use setting circles, but if you
should, here’s how:
1. Before using the setting circles, they will need to be
calibrated. Point the telescope toward a known object
whose coordinates you have looked up (R.A.-Dec.
coordinates or azimuth-altitude coordinates). Loosen the
two locking thumbscrews on the setting circles and turn
them so the coordinate values line up with the arrows,
then retighten the locking screws.
2. Once the setting circles are calibrated, the mount can
be moved either electronically or manually to specified
coordinates by referring to the setting circle readings.
3. The R.A. setting circle features three different scales:
the lower scale is used to indicate the right ascension
in Equatorial mode when operating in the Southern
Hemisphere; the middle scale is used to indicate the
right ascension in Equatorial mode when operating in the
Northern Hemisphere; the upper scale is used to indicate
the azimuth angle when operating in Altazimuth mode.
4. The lower scale of the Dec. setting circle is divided
into four quadrants of 90-degrees, used to indicate the
declination (when mount is operating in Equatorial mode)
or altitude angle (when operating in Altazimuth mode).
Use the proper quadrant when calibrating the Dec.
setting circle.
3.3 adjusting the r.a. axis Elevation (latitude)
1. Loosen the altitude lock knob located on the left side of
the mount
(Figure 14) about a quarter turn.
2. Push the spring-loaded elevation adjustment handle to
engage it, then turn it clockwise or counterclockwise
to set the R.A. axis elevation to your location’s latitude.
When the handle reaches its limit of rotation, release it,
then change its orientation and push it in to engage it
again and continue turning it.
3. Refer to the latitude scale and pointer on the right side of
the mount
(Figure 15). (If you don’t know your latitude,
consult a geographical atlas or look it up on the internet.)
For example, if your latitude is 35° North, set the pointer
to 35. The latitude setting should not have to be adjusted
again unless you move to a different viewing location
some distance away.
4. Retighten the altitude lock knob.
Note: It is normal to have slight elevation play on the Sirius
Pro AZ/EQ-G mount. The mount depends on the gravity of its
payload and its own weight to stay firm. Because of this, it is
recommended to end the elevation adjustment with an upward
movement. Whenever there is an upward over-adjustment,
lower the elevation first, and then crank the mount upward
again.
Figure 14.
Loosen the altitude lock knob before adjusting
the mount’s elevation angle.
Figure 15.
In EQ mode, line up your latitude on the scale
with the pointer (arrow).
Altitude lock
knob
R.A. clutch
wheel
Elevation
adjustment
handle
Elevation
adjustment
handle
Polar scope
mounting
plate
Latitude
scale
Arrow
(pointer)
a.
3.4 setting the Mount to alt-azimuth Mode
1. Refer to Section 3.3 to adjust the R.A. axis’s elevation.
2. Use caution when the latitude indicator gets close to
90 degrees. Do not turn the spring-loaded elevation
adjustment handle further when you feel it is blocked,
because it may mean that the R.A. axis has reached
the factory-calibrated position for Altazimuth mode.
TURNING THE HANDLE FORCEFULLY WILL DAMAGE
THE MOUNT .
3. Tighten the Altazimuth mode lock knob to secure the
R.A. axis in position for altaz mode operation
(Figure
16). Use a 5mm Allen wrench to tighten the knob if
necessary.
4. Also tighten the altitude lock knob on the left side.
Figure 17 shows the mount set in Altazimuth mode, with one
counterweight installed.
Summary of Contents for Sirius Pro AZ/EQ-G
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