‘Posit’ comes from the Latin positus
meaning ‘it is put in place’. I guess the best translation is ‘Given:’
The
formula we learn for earth convergency is:
Convergency =
change of long x sine mean latitude
using the given terms,
Convergency =
g x sine Lm or
= g.sin Lm, which is a shorthand version
of the same thing.
Conversion angle is half convergency
so
Conversion angle = (g.sin Lm)/2
This is not quite the same as g/2.sin Lm which easily
could be interpreted as being g/(2 sin Lm) but it’s all we’ve got so,
reluctantly,