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    Re: Magnetic Variation (Declination) Calculator
    From: Greg Rudzinski
    Date: 2009 Aug 4, 18:47 -0700

    Irv,
    
    At the magnetic pole the needle does point down rendering the magnetic
    compass useless. That leaves you with a gyro that seeks the geographic
    pole. The seeking process is not that stable but is better than a
    compass needle pointing straight down. At the geographic pole the
    magnetic needle will be pointing down but not straight down where as
    the gyro compass is trying to rotate 360� each day constantly seeking
    north back and forth. Your 180� variation is true the same way that a
    clock is correct twice a day. Steering by the Sun or stars is good but
    what if you are in that zone of early twilight. Polar navigation is
    problematic.
    
    Greg
    
    On Aug 4, 6:09�pm, "Irv Haworth"  wrote:
    > What am I missing? When one is in the magnetic pole area �the "needle"
    > points down (only is it horizontal at the equator)... To best of my
    > knowledge gyro compasses do not function too well at either pole. �Lastly in
    > these areas all directions are south..and let me add that the variation
    > between the GP and Mag P must be 180�
    > Now for another bevy ,in order to better meet the barrage..
    > Himself aka Irv
    >
    > -----Original Message-----
    > From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf
    >
    > Of Greg Rudzinski
    > Sent: Tuesday, August 04, 2009 5:46 PM
    > To: NavList
    > Subject: [NavList 9354] Re: Magnetic Variation (Declination) Calculator
    >
    > �If a navigator walks around the magnetic pole(as apposed to the geographic
    > pole) then it is the gyro compass that holds steady while
    > declination/variation changes rapidly. Therefor when near the geographic
    > pole use the magnetic compass to stay on track and when near the magnetic
    > pole use the gyro compass to stay on track.
    >
    > On Aug 4, 4:36�pm, Greg Rudzinski  wrote:
    > > 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.
    >
    > > On Aug 4, 2:33�pm, Greg Rudzinski  wrote:
    >
    > > > Brad,
    >
    > > > Manoj C. Nair of NOAA University of Colorado responded to my email
    > > > reguarding the zero result for 90� of latitude and said that the
    > > > current program recognizes latitudes above 89.999 as undefined. The
    > > > zero result must be a default number. I noticed another program
    > > > glitch where 13� West declination was displayed as 167� East.
    >
    > > > Greg
    >
    > > > On Aug 4, 10:20�am, Brad Morris  wrote:
    >
    > > > > Hi Greg
    >
    > > > > I just entered the pole for a gee-wiz kind of exercise. �To my
    > surprise, it returned zero, so I tried a location close to the pole. �That
    > returned non-zero, indicating that the software has some sort of bug.
    >
    > > > > Since I have no way to verify any other result it may present to me, I
    > will distrust the data. �How many other lat long locations give 'bad' data?
    > �How would I know?
    >
    > > > > Should NOAA fix this? �Certainly. How silly of them to permit an entry
    > which provides erroneous results.
    >
    > > > > Do navigators depend exclusively on a compass within 366 feet of the
    > north pole? �I sure hope not...
    >
    > > > > Best Regards
    > > > > Brad
    >
    > > > > -----Original Message-----
    > > > > From: NavList@fer3.com [mailto:NavList@fer3.com]
    > > > > On Behalf Of Greg Rudzinski
    > > > > Sent: Tuesday, August 04, 2009 1:03 PM
    > > > > To: NavList
    > > > > Subject: [NavList 9329] Re: Magnetic Variation (Declination)
    > > > > Calculator
    >
    > > > > Brad,
    >
    > > > > It looks like values above 89.998996� of latitude are all zero
    > > > > instead of 14� 24'W. Does NOAA need to correct this since it is
    > > > > only 366 ft from the pole?
    >
    > > > > Greg
    >
    > > > > "Confidentiality and Privilege Notice The information transmitted
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