Keep your eyes open tonight to catch a glimpse of a rare supermoon, as the harvest moon lunar eclipse will be visible across the UK tonight. A supermoon happens when the moon inches closer to Earth than usual, so it appears a bit larger in the sky. Tonight, the Earth will pass between the sun and moon and cast a shadow which will be visible in the top right corner of the moon. The supermoon may even be slightly orange because of the effect of moonlight shining through the atmosphere. The supermoon is one of three remaining this year.