# Math of a SunFlower...

Sorry, this may not seem to be directly related with the robotics. But I thought people on this group who build sun tracker may help me.
Given * the logitude and latitude of your position *date * time How to calculate the azimuth and elevation of the Sun position ?
NOTE that it is possible to track the sun without knowing explicitly its azimuth an elevation angles. I'm not interested in this. I'm looking for the equations which will return the Sun's azimuth and elevation angles corresponding to given date, time and location.
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The problem with using the time is something that is known (in horological circles at least) as, "The Equation Of Time". This deals with the fact that the Sun is exactly overhead at 12 Noon on only two days of the year. On other days, the Sun can be overhead as much as +/- 20 minutes from Noon.
This is the origin of the "Mean" (or average) in "Greenwich Mean Time"
Sorry - it didn't answer your question - but you might be interested.
"SunFlower" <sun flower> wrote in message

the
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wrote:

Is this the information from which you derived the length of the day to be 23H20?
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I've found some links about Sun's position and would like to share with you; http://www.nrel.gov/docs/fy04osti/34302.pdf http://rredc.nrel.gov/solar/codesandalgorithms/spa / http://members.allstream.net/~gneill/orrery.html (Issue #41) http://www.xylem.f2s.com/kepler/sun.html#twig02 (Amazon.com product link shortened) http://www.faqs.org/faqs/astronomy/faq/part3/section-5.html http://solardat.uoregon.edu/SunChartProgram.html
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Excellent.
Now thinking what I can do with it.....
A solar powered robot could certainly benefit.
Mike <SunFlower> wrote in message> I've found some links about Sun's position and would like to share with you;

(Amazon.com product link shortened)
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On Sun, Jan 09, 2005 at 12:26:02AM +1100, SunFlower wrote:

There are a number of steps that need to be performed, converting to and from different calenders and coordinate systems, performing computations, and the converting back. There's a wonderful book called "Practical Astronomy with your Calculator", by Peter Duffet Smith that goes through the calculations in great detail. The book I have is quite old - I got it mid-80s and I used it to implement a simple program to compute the positions of the sun, moon, planets, and other bodies, first on my HP 41CV calculator, and later in C. I still fire it up every now and then to see what's visible at my lat/lon. Good stuff.
-Brian
--
Brian Dean
BDMICRO - ATmega128 Based MAVRIC Controllers
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