ENJOY the night sky this evening because the moon only looks like this ‘once on a blue moon’.
Or every 2.7 years, to be precise.
The deceptive name ‘blue moon’ refers to the second full moon occurring within a single month, which occurs roughly every 2.7 years.
There are two measures of blue moons, one by full moons in a season, and the other by calendar month.
This moon will be the last calendar blue moon until January 2018.