Get to know lunar rays

A full Moon might bleach the sky and thwart your stargazing, but it's the best time to catch the magnificent lunar rays

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The worst time to look at the Moon is when it's full, right? Not necessarily. It's true that at full Moon, sunlight hits the surface head-on, flattening the appearance of its rugged landscape of deep craters, towering mountains and meandering valleys, showing only a flat, grey-and-white disc. But this direct lighting reveals something else: lunar rays - bright lanes of shattered rock and fine dust that fan out from impact craters.

While these are hard to see when the Sun is low in the lunar sky (when we see the Moon as a crescent or a gibbous disc), when the Sun's light strikes them from above during full Moon they shine. And with 2025's first supermoon coming on 7 October, there's never been a better time to see them.

Imagine you're standing on the Moon, 100 million years ago, watching a huge asteroid fall from the sky. As it hits, it blasts a crater – maybe 85km (53 miles) wide and 5km (3 miles) deep – out of the surface. It also sprays vast amounts of pulverised rock and dust away from the impact site, which arcs overhead. Where it settles, it leaves long rays of debris stretching back to the crater. That's how lunar rays were formed.

Catch some rays! Seven to spot

Find these craters for some lunar-ray-gazing fun during October's supermoon