NavList:

George, I'm not really sure what you aim at. Could there be some misunderstandings? With a gnomon you take *topocentric* measurements. Geocentric refers to the center of the earth and heliocentric to the center of the sun. The accuracy of measurements taken with a gnomon depend on how much the surface is leveled and the gnomon at right angle to it. I question whether your ground surface was really leveled. An artificial horizon might have been a better choice.

Marcel

On Fri, Jun 10, 2011 at 7:33 AM, G Becker <george@gwbeckerpls.com> wrote:

Hello, I mostly lurk here.. but I have a question.

Today, I stuck a 1/2" rebar into the ground as a gnomon and recorded the bearing and distance of the shadows over a few hours time. I used a 3" robotic total station, so the bearings and distances are very accurate. What I am looking for is the heliocentric ease/west. I have the geocentric state plane coordinates for the gnomon, the height of the gnomon, the beginning mid and end times of measurements, and the geocentric bearings and distances of the shadows. Am I on a wild goose chase doing it this way, or can the heliocentric east/west direction be found with the information I provided. Please look at the attached 2 page pdf file for a the graphic information. Any comments would be appreciated.

Thanks,
George
----------------------------------------------------------------
NavList message boards and member settings: www.fer3.com/NavList
Members may optionally receive posts by email.
To cancel email delivery, send a message to NoMail[at]fer3.com
----------------------------------------------------------------