Circle of Fire

Circle of Fire

May 21, 2012 - Manila time, the day of the most awaited phenomenon of the Annular Solar Eclipse. This phenomenon was being observed by the entire world since it is said to be a very rare event here on Earth.  Many took pictures of the said phenomenon as it transpires and of course amazement was seen in all of the faces of the witnesses as the eclipse began to form a circle of fire. It was said to be a breathtaking event which is why people who saw the eclipse feels so lucky for being able to witness as it transforms. 

A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partially obscuring the image of the Sun for a viewer on Earth. An annular solar eclipse can be observed when the Moon moves centrally in front of the Sun, but it is so far away from Earth that it appears smaller in the sky and cannot cover the Sun completely. The Sun's outer edges are then still visible and form a “ring of fire” around the Moon. As said, annular solar eclipse are like the total solar eclipse. They are very rare. They can only be observed during New Moon, when : 

• the Sun is near one of the nodes of the lunar orbit, so Earth, Sun and Moon form a straight line
• the Moon is at apogee
• and the observer is located in the path of the Moon's antumbra.

The reason why total solar eclipses do not happen every New Moon is that the lunar orbital plane - the imaginary flat surface whose outer rim is formed by the Moon's path around Earth - runs at an angle of approximately 5 degrees to the Earth's orbital plane around the Sun (ecliptic). The points where the two orbital planes meet are called lunar nodes. Only if the Sun appears near one of the two lunar nodes during New Moon so Earth, Moon and Sun form a straight line can a solar eclipse be observed from Earth.

The Moon's orbit around Earth is not round but forms an ellipse. This is why the distance from Earth to the Moon varies constantly. The Moon is at perigee when it is closest to Earth. The point of greatest distance is called apogee. Because of the varying distance, the Moon appears larger when it is at perigee. Although it is much smaller than the Sun, the Moon's apparent size then roughly matches the Sun's, as seen from Earth. For that reason, it can only cover all of the Sun's disk during a solar eclipse when it is at perigee. On the other hand, when the Moon is at apogee, its apparent size is so small that the Sun's outer edges are still visible and an annular solar eclipse can be observed. The Moon's shadow consists of three different areas: 

• Umbra, the innermost and darkest part  
• Penumbra, the lighter, outer part
• Antumbra, the area beyond the umbra that is only visible from Earth when the Moon is at apogee.  

To observe an annular solar eclipse, the observer must be located in the antumbra.

According to NASA, National Aeronautics and Space Administration, the next awaited solar eclipse this year is a total solar eclipse which will transpire on the 13th of November, 2012, Tuesday. It is said to be visible on the Southern Hemisphere of the Earth. 

sources:http://eclipse.gsfc.nasa.gov/SEmono/TSE2012/TSE2012.html
             http://en.wikipedia.org/wiki/Solar_eclipse_of_May_20,_2012
             http://www.timeanddate.com/eclipse/annular-solar-eclipse.html