[ATM] Small Dob Question: Alignment features needed for accurate encoder GOTO's?

[vorblesnak@peak.org]

Once the scope is collimated, and the basics of the mount are built,
bearing box, cradle and ground board, then you could align the tube in the
mount.  The classic method for this is to have two targets on opposit
sides of the scope.  North and south of the scope as it were.

You shim the scope within the bearing box and shim the bearings so that
the scope returns to the targets exactly as you rotate it through 180
degree altitude and azimuth turns.  You can mark the spot on the bearings
with masking tape, cut the tape, then align the cut edges for accuracy as
you test.

If you did this, you should in theory be able to remove any error from the
build and have a very accurate scope.

David Davis
Toledo, OR 97391

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