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Kieran Kelly said, about the folm "?aster and Commander" (which I haven't seen)-

>In the books O'Brian portrays the sacred rite of the noon sight thus: The
>first officer or navigator on a British warship, often with the aid of
>practicing midshipmen, would daily observe the sun for meridian passage. At
>the point when the sun finally begins to sink after culmination the officer
>turns to the Captain and says:
>
>"He's away. Noon Sir?" Note that the officer is asking the captain a
>question.
>
>The captain would reply:
>"Thank you Mr Smith. Make it so."
>
>The ships bell would then be rung signifying noon and the nautical day would
>begin.
>
>This sequence was repeated in virtually all O'Brian's books and was hinted
>at in the film. I love O'Brian's suggestion that the officer has to ask the
>Captain whether it is, in fact, noon. The passage of the sun across the
>meridian was not enough to presume that noon had occurred. On an English Man
>O' War it was noon when the captain said so and not a minute before or
>after. However I have a question: Why was noon regarded as being at the
>point when the sun began to fall. This technically was well past noon
>although it would have but a negligible impact on the calculation of
>latitude. Was this just a flight of fancy on O'Brian's part or did this
>actually happen? Possibly our English contributors could assist here.

Response from George-

I don't know what the noon ritual was in the Navy, and none of my books tell me.

But I think Kieran is right to be somewhat sceptical.

His point about the timing of noon is perfectly valid: that the altitude
remains stationary for so long that by the time that any drop is observed,
several minutes have elapsed since the Sun was at its highest. So it's  not
a useful way to determine the moment of noon.

It may be that any dialogue with the captain to agree that noon was past
(if indeed it was genuine and not just an invention in novels and films)
was simply to inform the observers that they could put their instruments
down and read out the maximum value. I would expect the sounding of 8
bells, for noon, to be related to the ship's clock rather than to the
uncertain timing of that noon sight.

Another important factor that comes in here is the time difference between
the moment of maximum altitude ans the moment of meridian passage, which
has recently been a topic of discussion on this list. For a frigate making
12 knots North or South, that time-difference can be as much as 5 minutes,
a serious error. It's the moment of maximum, rather than the meridian
passage, that a sextant picks out (badly) near noon.

For all that, the measurement of altitude provides a good measure of
latitude, quite independent of any timing, even if it's a rotten way to set
the time.

As I understand it, normal procedure was to measure a time-sight at some
moment several hours before (or alternatively several hours after) noon. If
a ship had a ship's clock (as distinct from the chronometer or
chronometers), which was to show local apparent time, to adjust it then. If
the sky was overcast, it would have to be adjusted from dead-reckoning of
any longitude changes. That clock reading what those on board would
naturally think of as "the time". If a ship's clock wasn't carried, then
the ship's bells would be timed according to GMT (shown by the
chronometer), then allowing for any offset due to known chronometer error
or a recent lunar observation, and for the equation of time. It would make
sense, to me, to sound the 8 bells for noon on that basis, and NOT on the
inadequate and inaccurate basis of a noon Sun time.

I don't know (but would be interested to discover) when use of a ship's
clock became prevalent, keeping (as near as possible) to local apparent
time, and used to time the ship's bells. In the days before chronometers
and lunars, and clocks, presumably  all that was avaiable for such timing
was the sandglass, turned every half-hour.
>
>SEXTANTS/QUADRANTS
>At the point in the movie where the noon site is being taken, Aubrey is
>instructing the ship's gentlemen - its young midshipmen - on the art of
>taking noon sights. There are about 9/10 of them all armed with a sextant or
>quadrant. About four of them are wielding sextants. Since the film is set in
>1805 I find this a bit difficult to believe. At that point the sextant was
>only coming into common use and would I believe have been a fairly rare and
>expensive item. I doubt if any English  warship would have carried four of
>them and certainly they would not have been entrusted to the tender care of
>a midshipman, who was only one rung up the totem pole from a common seaman.
>Am I right in this hypothesis?

I think Fred Hebard has answered this well.
>
>Furthermore, I read recently that until well into the 1800's, the noon
>sight - requiring less exactitude - was taken with the cheaper and more
>robust quadrant. The sextant was preserved almost exclusively for the more
>demanding lunar Distance where precision was vital.   If this is so then the
>foredeck scene on Lucky Jack Aubrey's ship was well adrift.

Cetainly Lecky advises (an the late 1800s) that in weather when there's
spray on deck, the sextant should be kept below to avoid corrosion, and an
octant used instead. This was for measuring altitudes, for which the octant
was perfectly adequate. The sextant would be reserved for its designed
purpose, for measuring lunars.

Presumably the film was set at some time in the Napoleonic wars, at which
date I think the admiralty were not supplying chronometers except on very
special expeditions. Otherwise, the ship's captain was expected to supply
his own if he considered a chronometer to be necessary. A chronometer was
FAR more expensive than a sextant.

The real-life frigate-captain Cochrane seems to have been the template for
both C S Forester's Hornblower novels (which I greatly prefer to the few
Aubreys I have read) and also for O'Brian's Aubrey. Cochrane's life was
almost unbelievably packed with action.

George.

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