NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Out of Date Almanac
From: Gary LaPook
Date: 2009 Dec 07, 18:42 -0800
From: Gary LaPook
Date: 2009 Dec 07, 18:42 -0800
Works fine for the sun and stars, not planets or the moon. For the stars just add the constant of 2.1' to GHA Aries, which is exact. The data for the sun will be correct within about two tenths of a minute for GHA and within three quarters of a minute in declination. Unfortunately these differences vary during the year so a simple constant, such as used for GHA Aries, wont work for the sun data. For practical navigation you can ignore the changes of positions of the stars or just zerox the star list from December 31, 2009 and carry it in the 2006 almanac. You can avoid this whole problem by getting a copy of Geoffrey Kolbe's Long Term Almanac which provides accurate data until 2050. gl Greg Rudzinski wrote: > Any opinions on using a Nautical Almanac that is four years out of > date? I bring this up because there are old almanacs available on > Amazon.com from $2 to $10. New Nautical Almanacs have gotten > expensive so my plan is to use a 2006 for the upcoming year 2010. > > -- NavList message boards: www.fer3.com/arc Or post by email to: NavList@fer3.com To , email NavList+@fer3.com
