Blue Moon on August 31, 2012

A Blue moon simply means that this is the 2nd Full Moon in one month.  Take time to go outside and enjoy nature — Ann.



Blue Moon coming! If you see the moon in tonight’s sky, you’ll see it’s nearly full. In fact, it’ll likely look like a full moon to you. Look at the calendar, and it’ll probably tell you (unless you’re in New Zealand, eastern Russia or a similar longitude) that this month’s full moon will fall tomorrow – on August 31, 2012. Thus many will call tomorrow’s full moon – and probably tonight’s nearly full moon as well – a Blue Moon. In this case, it has nothing to do with the color blue. It’s just a name for the second full moon in a month.

Read about the origin of the name Blue moon here

If the moon won’t be blue in color tonight or tomorrow night, what will it look like? It’ll look like any ordinary full moon, like the one depicted at the top of this post.

The moon will turn precisely full on August 31 at 13:58 Universal Time – the standard clock time at the prime meridian of 0o longitude. Translating Universal Time to the time zones in the mainland U.S., we see that the moon will reach the crest of its full phase at 9:58 a.m. EDT, 8:58 a.m. CDT, 7:58 a.m. MDT or 6:58 a.m. PDT tomorrow morning. Does that mean you should look for the moon at those exact times? No. Those times just indicate when the moon is precisely full. As always, you should look for the full moon to be pretty much opposite the sun all night long – rising around sunset, overhead around midnight, setting around sunrise.

Day and night sides of Earth at instant of August 31 full moon

Day and night sides of Earth at the instant of 2012 August 31 full moon (13:58 Universal Time). Credit: Earth and Moon Viewer

So even though tonight’s moon will look plenty full as it lights up the nighttime from dusk until dawn, the full moon – astronomically speaking – only represents a fleeting instant of time. It’s when the moon stands 180o opposite the sun.

How often do two full moons happen in the same month?

This August 31 full moon counts as extra special because it’s a Blue Moon – the second of two full moons to occur in a single calendar month.

Full moon image credit: Chris Ptacek