NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
The Complete On-Board Celestial Navigator Second Edition/ Astronomical Refraction
From: George Bennett
Date: 2003 May 3, 14:14 +1000
From: George Bennett
Date: 2003 May 3, 14:14 +1000
As a recent member of your group I see that there
has been some interest in TCO-BCN. For those who are not familiar with it, when
it was first published there was a Detailed Description of the first edition
(1999-2003) given in The Navigator's Newsletter, Issue 64, Summer 1999. For
those who are not members of the Foundation, the article has been reprinted in
my web site
(http://www.netspace.net.au/~gbennett/) and
can be downloaded and printed. The second edition covers the period 2003-2007,
so there is an overlap of one year between editions. The format of the new
edition is essentially the same as that of the first with the following
improvements: (1) highlighted tab markers have been provided to facilitate
quicker access, (2) In the Prediction and Identification Section, three stars
which give an optimum fix (considerations of altitude, magnitude and azimuth
distribution) have been chosen and marked and (3) A stiff back cover holds
the book in better shape.
I also see that there is some interest in the calculation of refraction,
particularly for non-standard conditions. In my paper "The Calculation of
Astronomical Refraction in Marine Navigation" which was published in The Journal
of Navigation (British), Volume 35, No.2, May 1982 formulae are given which
accurately approximate the generally accepted model of B. Garfinkel. The
formulae which I derived and show there, are used in the Nautical Almanac. I
"presume" that these formulae can be used at other than sea level,
provided a suitable pressure/height model or relationship is available.
