NavList:

So as I gather myself together for a bit of more sailing I have been looking into purchasing a proper sextant.

My nature dictates a sort of rambling research project into the evolution of the design features behind these instruments and I have come up against not really understanding the subject.

C Plath:   of course "the Rolls Royce" of sextants but...

Late in the game the "Traditional" seems to copy the C&P so one is left wondering what was happening in sextant design as these two companies developed products from the 80's or so on.

I would like to find a really nuts and bolts summary of design constraints and how they are addressed over time as sextants evolved which addresses specifically the challenges percieved and met in the later evolution of the instrument.

The features sets are of course of interest- seeing the polarized mirrors by C&P spring onto the scene but more nuanced- how is the frame arc milled for the worm?

C Plate employed different hobbing than C&P but also seems to have shifted late in came to a tooth form of the Ultra.

Can a good book be recomended?