NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: The Complete On-Board Celestial Navigator Second Edition/ Astronomical Refraction
From: Peter Fogg
Date: 2003 May 3, 14:53 +1000
From: Peter Fogg
Date: 2003 May 3, 14:53 +1000
Good on you, George. Welcome to the Nav
List.
----- Original Message -----From: George BennettSent: Saturday, May 03, 2003 2:14 PMSubject: The Complete On-Board Celestial Navigator Second Edition/ Astronomical RefractionAs 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.