NavList:

   

Reply

George Huxtable asked:

> It opens up another question, however.
>
> Assume that mariners were indeed universally accustomed to using the
> nautical day in their logs. Considering that the new Nautical Almanac had
> been especially prepared for their use, and indeed the Greenwich
> Observatory had been set up primarily for the benefit of nautical
> astronomy: then why were the astronomers so bloody-minded as to use the
> astronomical day, rather than the nautical day, for the Nautical Almanac
> tabulations? Conservatism, presumably. "That's the way we astronomers have
> always done it."

You are providing us with a reductio ad absurdum of your second premise.

The correct name of the publication in question is "Nautical Almanac and
Astronomical Ephemeris for the Year ...". In the preface we read "A work which
must greatly contribute to the Improvement of Astronomy, Geography, and
Navigation." (In this order!) This introductory sentence which describes the
general purpose of the Almanac gets easily lost in the excitement about lunar
distances in the several subsequent paragraphs.

The French emphasize their focus already in the title of their ephemeris, which
originally read: "La connoissance des temps", but soon had the addition "[...],
a l'usage des astronomes et des navigateurs". Again, the astronomers come
first.

Both publications (but the Connoissance a little more so) contain information
that was exclusively designed for use on land, such as the Jupiter satellite
eclipses, a map of the features of the Moon, aspects of planets, or the
Equation de l' Horloge. There is something for everybody: Land exploration,
surveying, pure astronomy (selenography), civil administration. And if I am not
mistaken, I even smell an astrologer hiding behind a corner.

Would not, for example, the tabulation of Jupiter satellites in nautical time
have been paradoxical? And the use of yet another time scale within one and the
same almanac rather awkward?

As to the purpose of the Greenwich Observatory: Sure it was set up for the
particular benefit of nautical astronomy, but astronomy is furthered by
astronomers, not seamen. Astronomers need ephemerides to improve their theory.
Before the almanacs came into existence, frequently required information was
spread out over different publications of varying accessibility, standards and
ease of use.

Herbert Prinz

   

Reply