AAJ Shines in the Sun Project

Post date: May 07, 2009 12:1:47 PM

The AAJ was introduced to the Sun Project by Prof. Dr. Udo Backhaus of University of Duisburg-Essen. It aims to promote astronomy experiments where the position of the Sun is measured so as to inform particpants about several aspects of it influence on our daily lives from the shadows to seasons, and also inform participants about the relationship between the Earth's position and orientation relative to that of the Sun. Following is an account of an experiment carried out by an AAJ entourage the aim of which was to obtain a measurement of the position of the Sun above the horizon, in conjuction with several other participants across the globe, to determine the shape of the Earth.

A simple visualisation is to imagine the Earth as a huge ball and the Sun is at a fixed position relative to this ball. Different people on different parts of the ball will see the Sun at different angles above the surface of the ball (their horizon). Getting the angle of the Sun at each known position in one go will provide the data necessary to determine the shape of the Earth (the more data the better!).

An AAJ team featuring Bobby Rodriques, Cleveland Gustard, and Errol Rickman met at Bobby's House where he has the Patio Floor marked for his telescope legs (position to be in perfect alignment with the North Star and the floor in level). This can be seen in the image below:

Because Jamaica is so near to the mid-day sun at the zenith (approximately 5.5 degrees), the team could not use the pencil point or the the pinhole vertically, so what they did, was to set the pinhole horizontally using a needle and thread to plumb it through the pin hole.

With the only 2 days of good sunlight occuring on the 23rd and the 24th of April the team is pleased with the results they got when the midday sun hit the lines at exactly 8 minutes after 12:00 noon local time. Bobby accounted for this by calculation of the Equation of Time.

The AAJ team hope to use the set up again for the students of Campion College to mark the charts with the the shadow as it reaches the 18.00 deg Declination mark. The team enjoyed doing this project and look forward to working out the radius from different measurements. A larger image of the setup follows.

For more details of the AAJ's activities in the Sun Project visit our Contact page.