If you and your significant other enjoy full moons this month is for you. August 2012 has two full moons and both will look full for four days rather than the usual three. Many refer to the second full moon in a calendar month as a “Blue Moon”. Another definition (historically more correct) is the third full moon of four occurring within a season. A blue moon fitting that definition occurs August 21, 2013. Sounds confusing? It is! Just go what works for you.
The traditional full moon name for August is the “Dog Day’s Moon”. The name is derived from the rising of the “dog star” Sirius at dawn. Other names associated with the last full moon of summer are the “Sturgeon Moon”, “Woodcutter’s Moon”, “Green Corn Moon” and “Wort (old-world word meaning plant) Moon”. To the Cherokee it is “the ripe corn moon”. The Oto called it “all the elk call moon”, and for the Zuni it is the “no snow on trial moon”. The Lakota Sioux called it “moon when the cherries turned black”. The second full moon, a blue moon, can be referred as the “corn moon” if you want to give it a name.
The month of August is named after Augustus the first emperor of Rome.
Technically the full moon is only a moment in time. For the first full moon of the month that moment occurs at 9:29pm MDT on Wednesday, August 1. The second full moon occurs at 7:59am MDT on Friday, August 31.
For the first full moon, the Moon will look full on the evenings July 31, August 1, August 2 and August 3. So which is closest to the true full moon? Usually there is an easy way for the casual observer to tell (except this month). A full moon always rises opposite the setting Sun. In general, the Moon that rises within a half hour of sunset is closest to the full moon. If the Moon is well above the horizon or has not risen until well after (greater than a half hour) sunset, it is not a full moon even though it looks like one. Let’s see what the data shows this month for Aurora, CO.
July 31 The Moon rises well before sunset
Sunset: 8:14pm MDT
Moonrise: 7: 04pm MDT
Difference: 70 minutes (Failed, Moon and Sun are not opposite)
Aug. 1 The Moon rises within 30 minutes of sunset
Sunset: 8:13pm MDT
Moonrise: 7:44pm MDT
Difference: 29 minutes (Pass just barely, Moon and Sun are opposite)
Aug. 2 The Moon rises within 30 minutes of sunset
Sunset: 8:11pm MST
Moonrise: 8:19pm MDT
Difference: 8 minutes (Pass Moon and Sun are opposite)
Aug. 3 The Moon rises well after sunset
Sunset: 8:10pm MST
Moonrise: 8:50pm MDT
Difference: 40 minutes (Failed Moon and Sun are not opposite)
This test works “most” every time for any full looking moon. The rule falls apart when the time of the full moon is close to local sunrise or sunset time. That depends of where you are on the Earth. People living in Europe, for example, will find the rule applies. We here in Aurora have four evenings this month where the moonrise is within 30 minutes of sunset, two moonrises just before sunset and two moonrises just after sunset, not the usual pattern.
For the second full moon, the Moon will look full on the evenings August 30, August 31, September 1, and September 2.
Aug. 30 The Moon rises well before sunset
Sunset: 7:34pm MDT
Moonrise: 6:49pm MDT
Difference: 45 minutes (Failed, Moon and Sun are not opposite)
Aug. 31 The Moon rises within 30 minutes of sunset
Sunset: 7:32pm MDT
Moonrise: 7:19pm MDT
Difference: 13 minutes (Pass Moon and Sun are opposite)
Sept. 1 The Moon rises within 30 minutes of sunset
Sunset: 7:31pm MST
Moonrise: 7:48pm MDT
Difference: 17 minutes (Pass Moon and Sun are opposite)
Sept. 2 The Moon rises well after sunset
Sunset: 7:29pm MST
Moonrise: 8:17pm MDT
Difference: 48 minutes (Failed Moon and Sun are not opposite)
A full moon is the only time the Moon is up all night and the only time a lunar eclipse can take place as it did in June. A full moon also sets in the west opposite the rising Sun providing us living near the front range really neat moonsets over the mountains, easily noticed by early morning west-bound commuters.
The August 1 and August 2 moonsets over the mountains in the predawn hours will be spectacular. The August 1 moonset (5:31am MDT) will occur before sunrise (5:58am MDT). The August 2 moonset (6:40am MDT) occurs after sunrise (5:59am MDT). You want to start watching before 5:10 am MDT. If you have the time, observe the sunrise. They are usually pretty good here in Colorado.
The August 31 and September 1 moonsets over the mountains in the predawn hours should be equally spectacular. The August 31 moonset (6:35am MDT) will occur just after sunrise (6:26am MDT). The September 1 moonset (7:38am MDT) occurs after sunrise (6:27am MDT). You want to start watching before 6:00am MDT.
Wishing you clear skies