NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Magnetic Variation (Declination) Calculator
From: Peter Hakel
Date: 2009 Aug 4, 17:08 -0700
From: Greg Rudzinski <gregrudzinski@yahoo.com>
To: NavList <NavList@fer3.com>
Sent: Tuesday, August 4, 2009 4:36:54 PM
Subject: [NavList 9351] Re: Magnetic Variation (Declination) Calculator
Professor Manoj C. Nair of NOAA was kind enough to answer all my
questions by email and he explained to me that due to the convergence
of longitude at the geographic pole there will be large change in
declination(variation) as you walk around the pole with compass in
hand but the compass needle will be steady and unchanged as it seeks
the magnetic pole. A simple concept that I should have been aware of.
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From: Peter Hakel
Date: 2009 Aug 4, 17:08 -0700
Polaris is the one star whose SHA in my calculations differed up to 2' from almanac values (declination was fine). I suspect that it is for this very reason. I did not check this explicitly because this is only an intermediate number that ultimately had no effect on the main result (latitude). Apparently, while the meridian convergence at the pole works against you in getting an accurate SHA, it then compensates when you "correct" the Ho of Polaris. Somewhat analogous to the magnetic compass issue, I suppose.
Peter Hakel
Peter Hakel
From: Greg Rudzinski <gregrudzinski@yahoo.com>
To: NavList <NavList@fer3.com>
Sent: Tuesday, August 4, 2009 4:36:54 PM
Subject: [NavList 9351] Re: Magnetic Variation (Declination) Calculator
Professor Manoj C. Nair of NOAA was kind enough to answer all my
questions by email and he explained to me that due to the convergence
of longitude at the geographic pole there will be large change in
declination(variation) as you walk around the pole with compass in
hand but the compass needle will be steady and unchanged as it seeks
the magnetic pole. A simple concept that I should have been aware of.
--~--~---------~--~----~------------~-------~--~----~
NavList message boards: www.fer3.com/arc
Or post by email to: NavList@fer3.com
To , email NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---
