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Fred,

Could you please give a little more explanation on using the sine curve
to approximate declination?  Maybe a short example?

Thanks,
Bill Allen

-----Original Message-----
From: Navigation Mailing List
[mailto:NAVIGATION-L@LISTSERV.WEBKAHUNA.COM] On Behalf Of Fred Hebard
Sent: Tuesday, May 18, 2004 3:21 PM
To: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM
Subject: Re: HMS Bounty

On May 18, 2004, at 5:44 PM, George Huxtable wrote:

> How could he have
> done this without a table of day-by-day Sun declination, that only the
> ephemeris or some other nautical table could provide?


Although not accurate to the minute, one can estimate the sun's
declination by means of a sine curve running from the equinox as zero
degrees to the solstice as 90, with an amplitude of 23.5 degrees.  The
ellipticity of the earth's orbit is accounted for, more or less, by the
varying number of days between the various equinoxes and solstices.  Of
course, how does one estimate a sine?  If one remembers the Taylor
expansion for it, that would be one way.  It's more likely, from
subsequent references in George Huxtable's post, that Captain Bligh had
a short table of declinations.  An adequate one could fit on one page.

Making heroes out of the mutineers is undoubtedly stretching the truth
on the Bounty mutiny.  But, as captain, it was Bligh's fault, just as
in any other catastrophe on a ship.  Apparently, however, his charms
were no match for those of some of the Tahitian maidens!

I told some of the boys who work with me the story of the Hawaiian
girls swimming out to Cook's ship to "welcome" him and his crew.  Some
of those boys are not too unlike some of Cook's sailors I would think.
One of them was ready to go to Hawaii on the spot!  He had missed that
Cook got there 230 years ago.

Fred Hebard

   

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