Once in a blue moon

Here’s something that only happens once in a blue moon. A blue moon! Well its not actually going to turn blue. It will be the same familiar colour as the full moon on 2nd of December and it will be  the same again tomorrow. Two full moons in the same month.

The lunar month (29.5 days) is fixed and a calendar month (28,29,30 or 31 days) is not. Once about every three years the difference catches up and offer the unusual prospect of two full moons in the same calendar month.

This is of no astronomical significance but its a great way to end a decade. If you have clear skies tomorrow why not put on a few layers go out  and have a look, take a picture or even go for a blue moon walk.

All the best for 2010.