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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: No Lunars Era
From: Alexandre Eremenko
Date: 2004 Dec 6, 16:19 -0500
From: Alexandre Eremenko
Date: 2004 Dec 6, 16:19 -0500
I think, Chauvenet explains very well, why there was no "Lunars era": "The navigator having found his longitude "by chronometer" wishes to verify it by "lunars". He takes a set of distances with upmost care and reduces them... His results are liable to the three sources of error above mentioned, and... the distance would produce in the longitude a mean error of 38 seconds in time. Now his chronometer must have performed very badly to be in error of 38 seconds... He takes another set of distances and finds a still greater discrepancy... and upon making port finds that his chronometer is right." This was written in 1868, when the time for the "Lunars era" was gone long ago:-) The time for the "Lunars era" was probably 60 or 70 years earlier when chronometers "were expensive". Notice that the price of a "good sextant" necessary for decent lunars was about 4 times that of the "good quadrant". of the same era. (I don't know much about the price of chronometers). In our time good chronometers are about 2-3 times more expensive than good sextants (on e-bay), but I understand that this is not a fair indicator:-) Alex.