The Moon's Shadow
A Total Solar Eclipse (TSE) occurs when the Moon's orbit around the Earth intersects with the Earth's orbit around the Sun at the time of a New Moon. Due to an amazing coincidence in scale of distance and size, the Moon is almost the same apparent size as the Sun. When the Moon completely covers the Sun, a TSE is seen. When the Moon is slightly smaller, an Annular eclipse is seen. A TSE occurs once every 18 months on average somewhere around the world. However, in any one location, a TSE is extremely rare occurring on average once in every 375 years.
During a TSE, in a narrow strip known as totality, the shadow of the Moon is cast upon the surface of the Earth. Only those located within the path of totality are able to experience the full awesome beauty of 'totality' - the central focus of the eclipse, when the Moon completely covers the Sun. Those outside of the path are only able to observe a partial eclipse, where the Sun is only partially covered by the Moon.
Solar filters are necessary to view the partial eclipse phases of an eclipse. However, filters are not required during totality as the Sun is completely covered by the moon. Totality is sublimely beautiful, creating changes in the environment all around and can create an expectedly emotional response. Anyone can enjoy this astronomical phenomenon - not just scientists and amateur astronomers.
Dr Kate Russo, 2013, Totality