Radius of curvature

edit

I have changed the formula for Rc near the end of this section to reverse M and N, since shen traversing along a meridian (with alpha = 0, i.e. facing North) one is moving along "M" the meridianal radius and when moving (e.g at the equator) eastward (for alpha = + 90 degrees) one is moving along "N" the radius of curvature in the prime vertical. JimC (C&B) 18:24, 7 January 2007 (UTC)Reply