NavList:

Debora Warner is very good on the development of US sextants with a fair amount of passing reference to European ones.  One fact I did learn from her paper was that Kollsman developed pendulous mirror peri-sextants simultaneously with the bubble variety.  I’d always assumed that pendulous mirrors came last, because that’s the order they came with Smiths peri-sextants.  I can remember seeing the title of a paper comparing the accuracy of bubble versus pendulous mirror, but now I can’t find it.  I think it was in an early ‘Journal of Navigation’.  Like they say, never move on until you’ve made a note. DaveP

I have attached a description of the development of aviation sextants.  gl