Not one, but two supermoons will appear in the skies this month; the first can already be spotted this evening (1 August) but those who also want to see the second one – a "blue supermoon" – will have to wait until the end of the month.
A supermoon is a full moon that appears 14% larger and 30% brighter than normal because the moon is very close to Earth. Despite this difference in distance and brightness, the phenomenon is barely visible to the naked eye.
The first supermoon this month will be visible tonight (on Tuesday evening, 1 August) from about 21:00. It will rise in the southeast and will be about 220,000 miles (357,530 kilometres) from Earth.
On the night of Wednesday 30 August to Thursday 31 August, the moon will be even closer to Earth, at about 357,344 kilometres. For comparison, the greatest distance the moon and Earth can be apart is 405,696 kilometres.
Once in a blue moon
The supermoons are best viewed from an area with dark skies and limited light pollution. Using a small telescope or binoculars offers the opportunity to see the surface of the moon in more detail.
Usually, a full moon only occurs once a month because the cycle of the moon takes 29.5 days. The last time two full supermoons appeared in the same month was in 2018. The next time this will happen won't be until 2037.
As two full moons in one month are rare, the second one is also called a "blue moon" – which is where the expression "once in a blue moon" comes from.
