X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 16 Sep 2008 11:04:47 -0400 Message-ID: X-Original-Return-Path: Received: from wind.imbris.com ([216.18.130.7] verified) by logan.com (CommuniGate Pro SMTP 5.2.8) with ESMTPS id 3132796 for lml@lancaironline.net; Mon, 15 Sep 2008 11:42:10 -0400 Received-SPF: none receiver=logan.com; client-ip=216.18.130.7; envelope-from=brent@regandesigns.com Received: from [192.168.1.144] (207-170-226-178.static.twtelecom.net [207.170.226.178]) (authenticated bits=0) by wind.imbris.com (8.14.2/8.12.11.S) with ESMTP id m8FFfOhk031788 for ; Mon, 15 Sep 2008 08:41:32 -0700 (PDT) (envelope-from brent@regandesigns.com) X-Original-Message-ID: <48CE822C.1050004@regandesigns.com> X-Original-Date: Mon, 15 Sep 2008 08:41:32 -0700 From: Brent Regan User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.2) Gecko/20040804 Netscape/7.2 (ax) X-Accept-Language: en-us, en MIME-Version: 1.0 X-Original-To: Lancair Mailing List Subject: Re: Motion of the North Pole Content-Type: multipart/alternative; boundary="------------010209080209090707060807" This is a multi-part message in MIME format. --------------010209080209090707060807 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Lorn writes: <<< Now if we take a look at the circumference of the Earth at the NP, we get, again according to Wikipedia, sin( 90° - 82.7° ) = .127. .127 * 21,600 nm = 2,743 nm. In other words the NP has done more than 2/3 of a complete circle at its' latitude. In other words, Detroit should be back to a 0° offset in about another 10 years.>>> The Earths North Pole (actually, magnetically a south pole) meanders. To calculate the field values in your (or any) area go here: http://www.ngdc.noaa.gov/geomag/magfield.shtml We use a magnetic field model to qualify the magnetometer during post installation setup of the Chelton ADAHRS. When you "spin" your compass after installation the software compares the triaxial magnetometer readings to the earth field for your location and date. For the installation to be valid you need to be within 5% of the anticipated values. At our location (North Idaho) the vector that points towards the North Pole has an elevation angle of 70 degrees below horizontal. Regards Brent Regan --------------010209080209090707060807 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit Lorn writes: <<<

Now if we take a look at the circumference of the Earth at the NP, we get, again according to Wikipedia, sin( 90° - 82.7° ) = .127. .127 * 21,600 nm = 2,743 nm. In other words the NP has done more than 2/3 of a complete circle at its' latitude. In other words, Detroit should be back to a 0° offset in about another 10 years.>>>

The Earths North Pole (actually, magnetically a south pole) meanders. To calculate the field values in your (or any) area go here: http://www.ngdc.noaa.gov/geomag/magfield.shtml

We use a magnetic field model to qualify the magnetometer during post installation setup of the Chelton ADAHRS. When you "spin" your compass after installation the software compares the triaxial magnetometer readings to the earth field for your location and date. For the installation to be valid you need to be within 5% of the anticipated values.

At our location (North Idaho) the vector that points towards the North Pole has an elevation angle of 70 degrees below horizontal.

Regards
Brent Regan
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