NavList:

Bill, you wrote:

" Do you know/recall what and how the sextant was to be
used and what positional information could be extracted?"

 

They could measure stars' positions relative to the axes of the spacecraft. The goal was to get the spacecraft's absolute orientation. Orientation is critical for rocket firings. Very early in the history of space flight, people considered these instruments for actual position fixing, but it's pointless (an amusing intellectual puzzle nonetheless).

 

The Apollo sextant was really just a telecope with the ability to be pointed very accurately relative to the spacecraft axes, and that is how it was used on missions. The orbiting astronaut could easily spot his comrades' spacecraft on the lunar surface by aiming in the right direction and looking through the eyepiece. It was also the best view of the outside. The windows on the Apollo CM were not that good.