Set to be the longest total solar eclipse this century, here’s when and where to catch the rare crossing of the moon and the sun. What is a total solar eclipse? A total solar eclipse occurs when the moon passes directly between the Earth and the sun, directly covering the sun’s surface. On Monday, 2 August 2027, a total solar eclipse will be visible across southern Spain, North Africa and the Middle East. Read more: New Zealand hotels sell out two years before historic total solar eclipse