Tonight is that rarest of things, once in a blue moon. Well, actually not as rare as you'd think, but nonetheless the second full moon to occur in August.
According to modern folklore, a blue moon is the second full moon to occur in a calendar month - something which happens once every two or three years, given that a calendar month can be anything from 28-31 days long, unlike the always consistent lunar month.
Why is it called a blue moon, you ask? That's because, as with many of our modern English words, the word blue does not refer to its colour (although pollution can make a moon appear blue at any time).
Instead it's thought to come from the Old English word belewe meaning betray.
And before you jump in the comments to tell us how wrong we are about the definition of a blue moon, we should say that this particular definition of a blue moon has only really been in use since 1946, and the term can also be used to describe the third full moon of four in a season - eg if there are four full moons in the three months of summer, the third would be called a blue moon.
Under that definition, the first full moon of August would have been the blue one and we'd all have missed it.
Anyway, the important point to note is that there's a second full moon tonight, a clear sky and some spectacular flying displays scheduled, not to mention some impressive fireworks. So get your cameras out (and send us the results!)
