Orion 8684 User manual

Orion Polar Axis Scope for
HDX110 EQ-G GoTo Mount
#8684
The Polar Axis Scope for the Orion HDX110 EQ-G mount
attaches externally to the front face of the mount head and
allows quick, accurate polar alignment of the mount for visual
or astrophotographic use. These instructions describe how to
set up and use the Polar Axis Scope. Please read them care-
fully before proceeding.
Included Parts
Qty Item
1 Polar axis scope with aluminum bracket
2 Socket head capscrews
1 1.5mm hex key
1 6mm hex key
Attach the Polar Scope
Install the polar scope assembly on the HDX110 mount with
the two socket head capscrews as shown in Figure 1. Use
the supplied 6mm hex key to tighten the screws.
The Polar Scope Reticle
The reticle includes star patterns useable in both the Northern
and Southern hemispheres (Figure 2). For the Northern
hemisphere it has representations of the Big Dipper and
Cassiopeia; for the Southern hemisphere is has four bright
stars of the constellation Octans. The celestial pole for either
hemisphere is marked by a cross. The large circle around the
cross represents the offset of Polaris from the actual North
Celestial Pole.
If the reticle image appears blurred, rotate the knurled ring of
the polar scope’s eyepiece to focus.
IN 505 Rev. A 10/13
INSTRUCTION MANUAL
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Figure 1. The polar scope attached to the HDX110 EQ-G mount.
Figure 2. Reticle pattern of the polar scope allows polar
alignment in both northern and southern hemispheres.
Bracket
Polar scope
Capscrews

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Align the Polar Scope
Before using the polar scope for polar alignment, it must be
aligned to the mount’s right ascension (R.A.) axis. There are
actually two calibration routines that must be performed.
Calibration #1 – Align the reticle to the rotating
axis of the polar scope
1. Choose a fixed object (Polaris at night, or a far-away
object in daylight). By using the two azimuth adjustment
knobs and the latitude jackscrew of the HDX110 mount,
point the mount so that the object is centered on the
cross in the center of the polar scope’s reticle. Tighten
the R.A. axis.
2. Now rotate the large knurled ring on the polar scope
exactly half a turn (Figure 3).
3. If the object remains at the center of the reticle after the
rotation, then the reticle plate is aligned with the polar
scope’s rotating axis and no adjustment is needed.
If the object deviates from the cross, then use the
supplied 1.5mm hex key to adjust the three small Allen
setscrews on the polar scope (Figure 3) to move the
object HALFWAY back toward the center of the cross
(Figure 4).
4. Repeat steps 1-3 a few times until the object stays at the
center of the reticle – on the cross – when rotating the
polar scope.
Note:
• When adjusting the Allen screws, loosen one screw only ¼
of a turn, and then lightly tighten the other two.
• Do not over-tighten the Allen screws; 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; otherwise, the pattern 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 the knurled ring
counterclockwise and then engage the reticle plate again.
Calibration #2 - Align the rotating axis of the
polar scope to the R.A. axis of the mount
1. Release the R.A. clutch and level the counterweight
shaft, orienting it parallel to the ground. Then lock the
R.A. clutch again.
2. Choose a fixed object (Polaris at night, or a far-away
object in daytime). By using the two azimuth adjustment
knobs and the latitude jackscrew of the HDX110 mount,
point the mount so that the object is centered on the
cross in the center of the polar scope’s reticle
3. Rotate the mount on its R.A. axis exactly half a turn.
Tighten the R.A. clutch after the rotation.
4. If the object remains at the center of the cross in the
polar scope, then the polar scope’s rotating axis is
aligned to the R.A. axis and no adjustment is needed.
5. If the object deviates from the cross, then adjust the
three thumbscrews shown in Figure 5 to move the object
HALFWAY back to the cross.
Note: When adjusting the thumbscrews, loosen one
thumbscrew very slightly while looking through the polar
scope, to see which direction the star moves. Then tight-
en one or both of the other thumbscrews to take up the
slack. If the star didn’t move in the desired direction, try
loosening a different thumbscrew. Each time you loosen
one thumbscrew, make sure to tighten one or both of the
others.
6. Repeat steps 1-5 a few times until the object stays at the
center of the reticle when rotating the mount on its R.A.
axis.
If Polaris drifted to here ...
... place Polaris here.
(half the distance)
Figure 4. If Polaris doesn’t stay centered when the R.A. axis is
rotated 180 degrees, adjust the three small Allen setscrews to move
it halfway back to center.
Figure 3. The large knurled ring provides convenient rotation of the
reticle.
Large
knurled ring
Adjust these
setscrews
(x3)
Focus ring

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Polar Alignment with the
Polar Scope
The polar scope can be used in both the Northern and
Southern hemispheres.
For Use in Northern Hemisphere: Rotate the reticle using
the large knurled ring on the polar scope so that the orienta-
tion of the Big Dipper and Cassiopeia match their orientation
in the sky. Locate Polaris (the brightest star near the North
Celestial Pole, or NCP) by viewing through the polar scope,
then use the altitude jackscrew and the two azimuth adjust-
ment knobs to move Polaris to the proper position in the FOV
of the polar scope. The proper position is the center of the
small circle superimposed on the larger circle surrounding the
cross (NCP).
For Use in Southern Hemisphere: In the polar scope’s reti-
cle, notice the string of four dim stars labeled “Octans” (refer to
Figure 2), which represent corresponding stars in the south-
ern constellation of that name. Rotate the large knurled ring of
the polar scope assembly to orient the reticle graphic with the
orientation of the four stars of Octans in the sky. Then use the
mount’s altitude jackscrew and the azimuth adjustment knobs
to carefully move the four stars into the four small circles of the
“Octans” graphic. When you’ve done that, your mount is polar
aligned!
1. With the mount now polar aligned, you can now tighten
the primary locking knob, and then tighten the azimuth
adjustment knobs, the azimuth and altitude lock bolts,
and the altitude lock knobs. (Refer to the manual for the
HDX110 EQ-G.)
2. We recommend removing the altitude jackscrew handle
once the polar-alignment has been done, to prevent
unexpected changes to the polar-alignment from
accidentally bumping it or catching a cable on it.
Another Method for Placing Polaris at the Correct
Offset Position
Because Polaris is not located exactly at the NCP, it is neces-
sary to determine the orientation of Polaris on the circle sur-
rounding the NPC (cross) on the reticle. Another way to do this
is to use the SynScan hand controller as follows:
At the end of the initialization of the SynScan hand control-
ler (see the SynScan manual), after entering the proper local
longitude, latitude, date, time, and daylight-saving time, the
hand controller will display the message: “Polaris Position in
P.Scope=HH:MM”. Imagine the larger circle in Figure 2 as a
clock’s face with 12:00 at the top, with the time indicated by
“HH:MM”, which stands for Hours and Minutes. You want to
position Polaris on the circle where the HOUR HAND would
be pointing at that time. So, for example, if the hand control-
ler displayed, “Polaris Position in P.Scope=03:30,” you would
place Polaris on the large circle at the point where the hour
hand of a clock would be at 3:30 a.m., i.e., halfway between
the imaginary 3 and 4.
Note that with this method there’s no need to rotate the polar
scope’s reticle to adjust the position of the small circle.
Tip: For this clock method to work, you have to be sure you
know where the “top,” or 12-o’clock point, of the large circle
is. This can be tricky to determine if your head is cocked at
a non-vertical angle when viewing through the polar scope.
To find the top of the large circle in the polar scope’s field of
view, use the latitude jackscrew to move Polaris up and down
in the field of view, and rotate the telescope in R.A. to ori-
ent the vertical line of the center cross to be parallel with the
motion of Polaris. When they are parallel, the 12-o’clock posi-
tion of the large circle is where Polaris intersects with the top
of that circle (assuming your mount was level to start with).
Thumbscrews
WARNING: Do NOT look at the Sun without a
professionally made solar filter on the telescope;
serious eye damage may result if you look at the
Sun with any unfiltered optical instrument. Do
not leave the telescope unsupervised around
children. Always cover the lenses when leaving the
telescope in direct sunlight.
Figure 5. Polar alignment requires adjusting the three thumbscrews
on the back plate of the polar scope.

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