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RE : http://www.fer3.com/arc/m2.aspx?i=115656
[NavList] A sextant calibrator
From: engineer---net.nz
Date: 13 Feb 2011 14:44

Dear Bill,

Congratulations on all your Sextant achievements ! They are ALL quite impressive, whether your repairs themselves, or your magnificent books. All highly speak about the qualities of their Author.

Just one question here which has puzzled me for years and even (many) decades.

Sextants "deliver" angles in degrees, minutes and tenths of arc-minutes, at least for the past one hundred years.

Why on Earth are their eccentricity calibration data then - for what I could observe on (very) many of sextants earlier used - ALWAYS given in arcseconds ? Why are they always given under the form of a table, when a "curve" graduated in arcminutes and tenths of arcminutes in regard of angles would be much easier to immediately use.

As we all know, there are times - and especially if and when working under pressure - ANYTHING which will make the Navigator task even just a bit easier is most welcome.

Never have I seen anywhere any convenient Sextant eccentricity curve, to an extent that when I knew I would likely be using a Sextant for some extended period of time, everytime I would made such a curve from the tabular data given in arc seconds ... it takes less than 5 minutes and makes your days and mostly your evenings (much) easier afterwards.

Any idea on your side as to why so much care has been taken for design and accuracy and why what would have been a quite appreciated "cherry on the cake" is unfortunately (most ?) always missing ?

... not even 5 minutes !

Is it simply because the Designers and Manufacturers, Troubleshooters and the so important Quality Control Technicians are not the End-Users ???

Thanks for your Kind Attention, thanks your view-point on this matter, and

Best Regards from

Kermit

Antoine M. "Kermit" Couëtte

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