Annular Solar Eclipse September 1, 2016 | The solar eclipse of September will be especially spectacular. So this date points to not miss: September 1, 2016. An annular solar eclipse occurs when the moon is so far from Earth that its apparent diameter is smaller than the Sun, thus blocking most of sunlight but leaving a ring of light. Thus, during the annular solar eclipse on September 1 the sky will not become completely dark, but will be a ring of light around the silhouette of the new moon..