Composite image of the total solar eclipse of August 21st 2017, from Idaho Falls, Idaho, USA. These wideangle photos were taken during the last minutes before, during and after totality. Solar eclipses occur when the Moon passes across the Sun as seen from Earth. During totality, the Suns inner corona (atmosphere) becomes visible around the disc of the Moon and a band of light remains near the horizon, beyond the Moons shadow. This eclipse tracked across a narrow portion of the contiguous United States from Lincoln Beach, Oregon, in the north west, to Charleston, South Carolina, in the south east. A partial solar eclipse was visible across the entire North American continent. Solar eclipses usually occur less than once a year, and can only be seen from a small area of the Earths surface.Dr Juerg AleanScience Photo Library