Supermoon: What was behind the Harvest Moon?

You may have spotted a particularly bright moon last night - here's why

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Last night you may have noticed a particularly bright full moon, but what caused it?

The supermoon phenomenon, which occurs when a full or new moon makes it closest approach to the Earth on its elliptical orbit, last night coincided with the Harvest Moon over the British Isles.

The Harvest Moon is the full moon that falls closest to the Northern Hemisphere’s autumnal equinox on 22 September, its name deriving from the light it allowed farmers to gather their crops during harvesting.

Throughout the year the moon rises, on average, about 50 minutes later each day. However, near the autumnal equinox this difference shrinks to only 30 minutes as the moon’s orbital path makes a smaller angle with the evening horizon.


Even though all full moons rise at sunset, the Harvest Moon – because it appears so much larger and brighter than normal full moons – means there is no period of darkness between sunset and moonrise and making it particularly spectacular.

According to NASA the Harvest Moon, and other supermoons, appear 14 per cent larger and around 30 per cent brighter than usual moons.