Six Wooden Arcs from an ?Astronomical Instrument

Six wooden arcs with joints that allow them to be joined into two longer arcs. The nature of the joints means only one configuration is possible. There are holes and notches for screws and fittings, and green staining suggests that some, at least, were copper. Some fittings are still in place. The arcs have a lip forming either a rim or a base.

Possibly from an astronomical instrument.