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Octant

Catalogue number:
PH*314493

Dimensions:
radius 16 inches

Discussion:
This octant clearly dates from the late eighteenth century. It has a mahogany frame and index arm. The boxwood scale is graduated every 20 minutes from 0^o to 90^o and read by transversals to 2 minutes of arc. The top of the scale is numbered counterclockwise for zenith distances. There is also a back sight and a back horizon glass that can be used to measure angles greater than 90^o.

Further Information:

Octant