NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From Chauvenet to Dutton: Nav. & Naut. Astro.
From: Frank Reed CT
Date: 2004 Dec 5, 18:04 EST
From: Frank Reed CT
Date: 2004 Dec 5, 18:04 EST
I first encountered the title "Navigation and Nautical Astronomy" as
Dutton's textbook on the subject. It's the one that was a standard at the US
Naval Academy in the 1940s. I recently was browsing through an
1865 predecessor with the same title, author J.H.C. Coffin, and found
this in the preface:
"This treatise was originally prepared by Prof. Chauvenet to be used
in manuscript by th students of the Naval Academy. With Bowditch's Navigator,
oral instruction, the use of instruments, and computation of examples, it
constituted the course of instruction in Navigation and Nautical
Astronomy."
I thought it might be interesting for some who know Dutton that it also
goes back to Wm. Chauvenet.
By the way, Coffin/Chauvenet have this to say about dip:
"the dip is decreased by refraction by 0.074 or nearly 1/12 of it" ['it'
being the geometric dip without refraction] and:
" But from the irregularity of the refraction of horizontal
rays, the dip varies considerably, so that the tabulated dip for the height of
16 feet can be reiled on ordinarily only within 2'. When the temperatures of the
air and water differ greatly, variations of the dip from its mean value as great
as 4' may be experienced. In some rare cases, variations of 8' have been
found.
The dip may be directly measured by a dip-sector. A series of
such measurements carefully made, and under different circumstances, oth as to
height of the eye, temperature and pressure of the atmosphere, and temperature
of the water is greatly needed."
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois
[ ] Mystic, Connecticut
[X] Chicago, Illinois