Focus, Tilt and Centering Adjustments:
The focus, tilt and centering adjustments are shown in
Figure Four. If you have the lens installed at the factory it will be
close when you get it, but it can be tedious getting it perfect.
Figure Four: Focus, Tilt and Centering Adjustments
Focus can be adjusted with the three sets of push/pull screws
around the periphery of the lens plate (marked P/P). They are
adjusted by loosening one screw of the pair slightly, and tightening
the other. You are trying to set focus to an accuracy of about 0.001
inch (25 microns), which is only 1/25
th
turn of the screw, so a very
delicate touch is required when close. To set the centering, use the
push/pull screws labeled C/C around the edge. Note that this
adjustment can only be done when the focus screws are a little loose
so the plate can translate. The proper order of adjustment is:
A) Inside, in a room:
1) Set the focus close to correct in the center of the image
2) Translate the lens so the centering is quite good
3) Set the focus in the center carefully
B) Outside, under the stars
1) Adjust the tilt of the lens plate to get the best focus
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