Update on Blue Moon

I ran across a couple of interesting articles/pictures related to yesterday's blue moon that I wanted to share.  The first is an article about the misconception that a blue moon is the second full moon in a calendar month.  It turns out that this is the modern definition, but there's a historical definition that is somewhat different.  The full article is from Sky & Telescope.  If you're interested in the history of terms/phrases, I encourage you to read this article.  It concludes that:

"Seasonal Moon names are assigned near the spring equinox in accordance with the ecclesiastical rules for determining the dates of Easter and Lent. The beginnings of summer, fall, and winter are determined by the dynamical mean Sun. When a season contains four full Moons, the third is called a Blue Moon."

So it turns out that a blue moon being the second full moon in a calendar month is not quite accurate.  The point I'd like to make is that regardless of your definition of a blue moon, modern vs. historical, the moon is still not blue during a blue moon.

As I mentioned in my previous post titled "Are Blue Moons Really Blue" a change in the color of the moon is the result of atmospheric (Earth's) effects.