NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Newbie - Variation Question
From: Pierre Boucher
Date: 2002 Feb 11, 11:02 -0500
From: Pierre Boucher
Date: 2002 Feb 11, 11:02 -0500
Hi Andrew, That is the way the french deal with variation (declinaison) The basic formula being: True + Variation = Magnetic They consider : West variation as positive and East variation as negative So the negative East variation is added to True to get the Magnetic. Hope this help, Pierre Boucher >I realise the list is for non electronic navigation methods but I need some >confirmation on an issue of magnetic variation. > >I recently purchased a hand held GPS to back up my celestial on my first >offshore trip (solo). Whilst I was familiarising myself with the unit the >other day, I found after much head scratching that the unit actually ADDS >easterly variation to true to get a magnetic heading readout. > >I was always taught that "variation east, magnetic least" - all my >navigation text books including Bowditch back this up. > >I contacted the Australian importer of the GPS this morning who said they >had been aware of the problem for 18 months, had taken the issue up with MLR >France ( the manufacturer) >and were advised that it was the way that the French deal with variation( ie >add rather than subtract Easterly variation to get magnetic course). The >importer said they were happy with this explanation. > >Anyway, I just wanted to confirm that the world over that Easterly variation >is subtracted from true to get magnetic. If it isn't, well at least I've >learned something today. > >Thanks in advance. > >Andrew ************************************************************************** X XX X Pierre Boucher N XXX XX formation en navigation de plaisance XXXX XXX Ste-Therese (Quebec) Canada XXXXX XXX XXXXXX XXX la "VOILE"... le reste n'est que du vent... XXXXXXXXXXXXXX ''Sail, Sail !''... the rest is only wind XXXXXXXXXXXX XXXX EMAIL: pboucher@lavoile.com XXX "http://www.lavoile.com" **************************************************************************