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- Place the tube in a horizontal position either in its mounting or lying
flat on a table.
- Stand about ten or fifteen feet from the mouth of the tube and look
at the main mirror. If the mirror is approximately square in the tube so
that its axis is parallel to the sides it will appear to be circular and
one can observe the image of his face in the mirror. If the mirror "sees"
only the sides of the tube or presents an elliptical reflection, have an
assistant turn the adjustment nuts on the mirror cell until the mirror seems
to be square in the tube.
- Point the telescope toward an evenly illuminated area such as a light
colored wall or the day-time sky. Remove the eyepiece, rack the eyepiece
holder out as far as it goes and peer into it, making sure that the eye
is centered over the hole. If the telescope is properly collimated it will
appear as illuminated in figure 1. If the diagonal mirror is poorly adjusted
it will not appear circular and the reflection of the eye will not be
centered (see figure 2). Adjust the three screws of the diagonal holder
until it appears as in figure 1. If the primary mirror is poorly centerd
the reflection of the secondary mirror and its supports will not be symetrical
but will appear as in figure 3. Have an assistant turn the three adjustment
nuts on the mirror cell until the image is symmetrical as in figure 1.
- Repeate step 3. The telescope is now collimated well enough to form
an acceptable image, however in order to utilize the best performacne possible
the following adjustments on a start must be made.
- Select a second or third magnitude star and train the telescope on
it using a 24 or 16mm eyepiece. Back the eyepiece about 1/2" out of
focus, or until the star image appears as a central dot surrounded by 5
to 10 concentric rings. If conditions of "seeing" are fair and
the atmosphere is steady the image will be relatively stationary if the
telescope is well aligned the rings will be very concentric as illustrated
in figure 4. If not the rings will be off center as in figure 5. Have
an assistant adjust the three wing nuts on the mirror cell until the image
resembles that in figure 4.
- Replace the eyepiece with one from 6 to 12 mm focal length. Repeat
step 5. The telescope is now collimated well enough to see many objects
very well. If it is desired, however to work with double start to see planetary
detail or to see very find detail on the moon it is necessary to collimate
the telescope to even a greater degree of accuracy.
- Exactly focus a high power eyepiece on a second or third magnitude
star. If the air is steady the star image will be an airy disk surrounded
by a defraction ring. If the telescope is perfectly collimated the image
will resemble firgure 6.
If it is slightly
off center the diffration ring will not be evenly illuminated (see figure
7).
- Adjust the nuts on the mirror cell until the ring is of equal brightness.
The telescope is now perfectly collimated. It should be checked periodically
to see if the collimation has changed.
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