Tonight there's a once in a blue moon event... yes, a blue moon. And that's a joke you're going to hear repeatedly for the rest of the day.
So what is a blue moon?
A blue moon sadly isn't actually blue (unlike a red moon) but refers to a unique chronological coincidence. There's two slightly different definitions that are used:
1) It is when we get a second full moon within the same calendar month.
2) It is the third full moon of a four moon astronomical season (a season normally has three).
The second definition is broadly considered to be the more 'correct' definition by astronomers, but both are widely used and in both cases the result is the same: A fairly rare event.
The reason this happens - but only rarely - is because the lunar calendar and the Gregorian calendar (ie: the one we actually use) are slightly different, with the lunar calendar only 29.53 days long. Given how this syncs up, it means that we'll tend to get a blue moon once every two or three years.
And there's a blue moon tonight?
Yes, if you're in the UK! Whilst both hemispheres will see the same moon (albeit each side will think the other is seeing it 'upside down'), there is technically only one moment where the moon is at its fullest... and it presumably helps if it is night time too. Today the UK is the lucky winner. Tonight is our first blue moon since August 31st 2012 - our next is on January 31st 2018.
How can I photograph it?
If you want to take really good photos of the Moon, it helps to have some extra equipment, as simply holding up your camera may not produce the best results. For example, get a tripod so that your camera will remain steady, and if you can use a remote shutter device (such as an IR remote or a phone app) to take a photo, the camera won't wobble when it comes to shooting.
Obviously having the right lens helps too, and given how far away the moon is, a zoom lens is probably best suited to this. In terms of settings, our pals at Digital Camera World recommend ISO100, f/8 at 1/125 on a 70-300mm lens.
It also recommends tweaking the settings to minimise mirror bounce (the physical movements of the inside of your camera when taking photos could blur the shot slightly), and suggests that auto-white balance might be a better option than using a white balance that has been preset by daylight. Fiddling with the contrast and sharpness in post-production should enable you to pick out more detailed features on the Moon's surface.
Whilst the Moon is still going to be bright enough to be visible in built-up areas, you'll maximise your chances of capturing it well if you're not surrounded by other light. So go out into the countryside. Plus, being somewhere dark means there's more scope for long exposures, which can reveal a tapestry of stars that are hidden to the naked eye.