# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

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Re: A simpler Bygrave ?
Date: 2010 Feb 8, 09:12 -0500

Hi Hanno

You may be on to something.

May I suggest that you construct one and solve some navigation triangles using it.

This will help us to understand your concept and way forward.

Best Regards

From: navlist-bounce@fer3.com [mailto:navlist-bounce@fer3.com] On Behalf Of Hanno Ix
Sent: Sunday, February 07, 2010 5:44 PM
To: NavList@fer3.com
Subject: [NavList] Re: A simpler Bygrave ?

Gentlemen:

So far I have not received any answers why a single scale Bygrave  never has been implemented. I suspect it has to do with the use of such a thing, however, it is not clear to me. However, I am no sailor.

There must be some of you so knowledgeable in CelNav who have an opinion. Please, just drop me a note.

Regards

H

PS, again: in the formulae below  x=1...89; should be replaced by x=(1:89)/180*PI

From: Hanno Ix <hannoix@sbcglobal.net>
To: NavList@fer3.com
Sent: Fri, February 5, 2010 4:43:47 PM
Subject: A simpler Bygrave ?

Ageton's method can be, mathematically at least, performed with a single scale,  log cosec or log sec.

Therefore, it should be possible to create a version of the Bygrave that contains just a single scale of cosec or sec.

For convenience, one could add one or more cursors as convenient.

Note:  The CelNav on Starpath's Emergency Navigation Card can be reduced to this method.

Just compare their N(x) Table with :   n(x) = logn(cosec(x))  for x=1...89;

I can see certain mechanical advantages of a one-scale Bygrave. I am sure this has occurred to somebody else long ago, too.

Therefore I ask why, despite its seeming simplicity, such a version has never been implemented.

Regards

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