After several hours of angle grinder work, the fine adjustments of the observatory crown are finally complete. The surface is very level with very few irregularities. Two hundred point measurements with a laser indicate a surface accuracy of 0.5 mm.
The next operation is to bolt the lower rotation ring to the crown. The ring is made of four segments. These must be adjusted such that the ring is circular to millimeter accuracy.
The lower half of the telescope pier’s foundation is visible through the entrance. This is cast directly on the basement rock, approximately forty centimeters below the surface of the gravel. The upper, pyramid-shaped part of the pier’s foundation will be cast on top of this after the observatory dome is in place.
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