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Thanks to Paul Hirose for correcting my staement that "Astronomical Time ran
12 hours later than ordinary civil time." He is, as usual, absolutely
correct. The Astronomical day started at noon, 12 hours after the
corresponding civil day started, so from then on the Astromical Times on the
same day were 12 hours less.

Perhaps I should add the astronomical time at midnight was 12 hours, and
after midnight it continued to increase up to 24 hours as the next noon
approached. But over that morning , midnight to noon, when astronomical time
was 12 hours greater than civil time, the dates differed by one. The civil
date changed at midnight, just as we're used to now, but the astronomical
date didn't (until noon), so over the morning the astronomical date lagged,
by a day less than the civil (calendar) date.

I find the whole business dreadfully confusing, and hope I haven't spread my
own confusion to Navlist, too badly.

What I haven't resolved in my mind is how day-names were treated in an
almanac which worked in astronomical time, before 1925. Surely, Sunday
didn't turn into Monday on the stroke of noon, or they wouldn't have been
able to hold morning and evening church Sunday services on the same day.
How, then, did they tie together date (day number of month) with day-name,
in Astronomical time?

George.

contact George Huxtable, at  george@hux.me.uk
or at +44 1865 820222 (from UK, 01865 820222)
or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.


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