Hi Adam....I checked distances at the equator to make sure that Google Earth was measuring 1' as 1nm. That was done to validate how Google Earth measures distance.
I was using the sun, and no I did not put corrections in for semidiameter or dip.
The assumed position was a quite far away so it is no surprise that the error was on the large side. What I think now after more consideration is that the error of 1 degree 8' does not necessarily translate into 68nm between assumed and actual position. Rather, if I draw an azimuth through the assumed position and advance a perpendicular through the azimuth 68nm toward the sun, then that perpendicular should more or less cross through my actual position on my back porch. So using Google Earth to double check that my porch was 68nm from my assumed posistion was incorrect.
I still can't figure out why Google Earth doesn't measure 1nm between 0N,0W and 0N 1.0W at the equator.
Last edited by RandyBC; 05-02-2010 at 10:59 PM.