Look up tonight in France for rare 'blue' supermoon

Two rare phenomena will occur at once, for the last time until 2037. Here is how to get the best view

A view of a supermoon in the sky in France
The moon will appear brighter and larger in the sky due to a dual phenomenon of a ‘blue’ and 'super' moon
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A rare 'blue supermoon will be visible from France tonight (August 30) as two astronomical phenomena coincide for the last time until 2037.

A ‘blue’ moon is an ‘extra’ full moon. It means that this year will have 13 full moons instead of the usual 12. It comes after the ‘super’ Sturgeon moon that was visible on August 1.

As well as a ‘blue’ moon, tonight’s moon will also be a ‘super’ moon. This means that the moon itself will be as close as possible to Earth, making it appear larger and brighter than usual. It will be 363,000 kilometres away, compared to its usual 384,400 kilometres; and appear 14% larger than usual.

The moon will also be visible on Wednesday and Thursday night, although is expected to be at its brightest tonight or tomorrow.

The US space agency NASA has said that only 3% of ‘blue’ moons are also ‘super’ moons, making tonight’s lunar event rare. It will not happen again until January 2037; 14 years away. The phenomenon only occurs once every 10 to 20 years.

The proximity of the moon can create large tides on Earth, and also disrupt sleep for some. One 2013 study in the scientific journal Current Biology said that “deep sleep drops by 30%” towards a full moon. Some may take five minutes longer to fall asleep, and sleep for 20 minutes less overall, it said.

And yet, despite its name, the moon will not appear blue in colour. Its shine may even appear slightly more orange than usual, said the scientific website Future-sciences, because it will appear low on the horizon.

Similar to a setting sun, light from the body will appear slightly more yellow and orange because these colours will be more visible than blue and violet wavelengths.

The phenomenon itself is also the source of the English expression ‘once in a blue moon’, to describe something that happens only very rarely, if at all.

In French, the equivalent expression is ‘tous les trente-six du mois’, which translates as ‘every 36th of the month’ - again, as a way to describe something that is very rare or ‘never’ happens.

How to get the best view of the blue supermoon

  • Travel away from cities and built-up areas to avoid light pollution
  • Look up at 01:35 GMT (03:35 French time, one hour ahead of BST in the UK), when the moon will be at its fullest
  • The naked eye will be enough, but you can also use binoculars or even a telescope

It is also worth keeping an eye on the weather forecast as cloud cover will, unfortunately, obstruct the view.

Heightened hurricane

In the US, the weather and the moon may also be even more closely connected. The National Hurricane Center (NHC) has warned that the lunar phenomena could intensify the strength of Hurricane Idalia, which is set to hit Florida within hours.

Tides of three to four and a half metres are expected in the most affected areas, said the NHC, which classified the hurricane as a ‘major’ and ‘dangerous’ weather event; a category 4 out of 5 hurricane on the Saffir-Simpson scale.

The hurricane will first make landfall in Florida, before passing to Georgia, South Carolina, and North Carolina. Residents have been warned that they may need to evacuate at short notice.

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Pictured: Lunar eclipse as it appeared in south-west France