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Russell Sher wrote:
>
> Hi - I've just subscribed. Does anyone know the formula for calculating
> meridional parts if given the Latitude ?
> Cheers
> Russell Sher

>From "The Calculator Afloat"

	M=7915.7045 x log tan (45d +L/2) - 23.2698 sin L

Example:  Our position is Lat 32d 14.7'N, Lon 66d 28.9' W, and we wish
to determine the course and distance to a point near Chesapeake Light,
in Lat 36d 58.7'N, Lon 75d 42.2'S, be Mecator sailing.

	L1      32d 14.7'N
	L2	36d 58.7'N
                ----------
	l        284.0' n        l = difference of L1 and L2

M1 = 7915.7045 x log tan(45d + 32.2450d/2) -23.2689 x sin 32.2450d x sin
32.2450d
     2045.7409 - 12.4149 = 2033.3

~ = asbsolute value

	L1      32d 14.7'N       M1	2033.3
        ~                        ~
	L2	36d 58.7'N       M2     2377.0
                ----------              -------
	l        284.0' n 	         343.7

next step difference in Lon in min of arc:

	Lon1    66d 28.9' W
         ~
        Lon2    75d 42.2' W
                -----------
         DLO       553.3' W

	Tan C = 553.3'/343.7 = 1.6098
	
Therefore:  course is N 58.1522d W; the course to steer will be Cn
301.8d
	
	Distance  D = 284.0'/cos 58.1522d  = 538.2206  or 538.2 miles

Hope this will help

--

Learning the Hard Way!!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Millard Kirk KB8YQO 	Email - mkirk@marshall.edu
 116 Lewis Ave	     	Homepage- http://webpages.marshall.edu/~mkirk/
 Barboursville, WV      A West Virginia Blue Water Sailor
 25504                  (304) 736-6544
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


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