|
|
|
|
|||||
|
||||||
Subject: Sextant accuracy and deflection of the vertical
From: dpstephen (dpstephen@XXX.XXX)
Date: Tue Mar 18 2003 - 16:18:13 EST
At Fred's request, here is a site where you can get information on
deflection of the vertical and a program that will allow you to calculate
delflection for a given location.
http://www.ngs.noaa.gov/GEOID/
The program on that web page called deflec99 calculates deflections for
given locations.
Unfortunately the section of the page titled "what is a deflection of the
vertical" is under construction and not working. However as I understand it
astronomical latitude and longitude (from sextant or theodolite) are based
on angles related to the vertical as defined by gravity (through water
horizon or bubble horizon) and geodetic latitude and longitude are related
to a line normal to the ellipsoid. I beleive that GPS latitude and longitude
are geodetic. If I am confused here please correct me.
Doug
|