> Also in the library, dotted here and there, are objects connected to O'Brian. [...] a device for determining latitude, Awkward, it's not like astrolabe, or p

> Also in the library, dotted here and there, are objects connected to O'Brian. [...] a device for determining latitude, Awkward, it's not like astrolabe, or perhaps sextant, are difficult words for the intended audience - https://en.wikipedia.org/wiki/Mariner%27s_astrolabe https://en.wikipedia.org/wiki/Mariner%27s_astrolabe