Orion 102mm EQ - Manual (Page 18)

Once you are ready to collimate, look into rear opening of the
tube. If your telescope is out of collimation, it will resemble
Figure 2a, a properly collimated scope will resemble Figure
2b. The direction of the misalignment in your telescope may
differ from Figure 2a, but the diagram will give you the gen-
eral idea of how things will look.
Note there are six alignment screws on the back of the opti-
cal tube, three large and three small. You will need 3mm and
2mm Allen wrenches to turn these screws. These alignment
screws push and pull the mirror cell in order to tilt it. When
you loosen or tighten one of these screws, the other five
screws must be adjusted as well to keep the proper amount
of pressure on the back of the mirror cell. By making slight
adjustments to how much the screws are tightened and loos-
ened, you will change the alignment of the primary mirror.
Look into the rear opening of the tube and locate the black
crescent that shows the telescope is out of alignment.
(Figure 2a). Note which way the front of the telescope would
need to move in order to “fill” that black crescent and resem-
ble Figure 2b. Then look at the back end of the telescope and
locate the alignment screw that is in the direction that the
front of the telescope needs to move. For example, if the view
in your telescope resembled Figure 2a, then you would want
to move the front opening of the telescope scope to the right.
Then the alignment screw you would start with would be the
screw on the right as shown in Figure 3.
Your actions now depend on whether this alignment screw is
a small or large screw. Please note that you will be working
to adjust the mirror cell by keeping all the screws not too
loose and not too tight. Follow the steps listed below careful-
ly and refer to the figures that accompany them.
2
Figure 2a: If the telescope’s optics are out of alignment the
view through the rear opening of the telescope will resemble
Figure 2a.
Figure 2b: With the optics properly aligned the view through the
rear opening of the telescope will resemble Figure 2b.
Front of
telescope
Secondary
mirror
Reflection of
your eye in
secondary
mirror
Secondary
reflection of
inside of tube
Reflection of
inside of tube
(misalignment)
Front of
telescope
Secondary
mirror
Reflection of
your eye in
secondary
mirror
Figure 3: If the view through
the rear opening of the telescope
resembled Figure 2a, then the
alignment screw you would start
with would be this one. The
actual first alignment screw you
would pick will vary depending on
which way the front opening
would need to move in order to
“fill” the black crescent.
Figure 2a Figure 2b
Figure 3