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Bill,

Dan Allen covered this well.

Fred

On May 19, 2004, at 12:38 PM, William Allen wrote:

> 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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