The traditional full moon name for September is the “Harvest Moon”. The harvest moon is some what unique in that it is assigned to the full moon closest to the autumn equinox. That means it can also be the name of the full moon in October. The harvest moon name is obviously a reference to farmers working late into the night harvesting crops by the light of the full moon. The Moon also rises at a steep angle giving the Moon more time above the horizon and much shorter times between moon rises.
Other names include the “Fruit Moon”, “Dying Grass Moon”, “Wine Moon”, “The Singing Moon”, “Blue Corn Moon”, “The Elk Call Moon”, and “Barley Moon”. The Lakota Sioux called it the “Moon where Calves Grow Hair” or “Moon when Plumes are Scarlet”. The Taos call it “The Yellow Leaf Moon” and the Oto call it “Spider Web on the Ground at Dawn Moon”.
The month of September is derived from Latin meaning “seven”. It was the seven month of the Roman calendar until 46 BC when the beginning of the year was changed to from March to January.
Technically the full moon is only a moment in time. For September that moment occurs at 9:20pm MDT on Saturday, September 29. The Moon will look full on the evenings September 28, September 29, September 30 and October 1. 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.
September 28 The Moon rises well before sunset
Sunset: 6:47pm MDT
Moonrise: 5: 49pm MDT
Difference: 58 minutes (Failed, Moon and Sun are not opposite)
September 29 The Moon rises within 30 minutes of sunset
Sunset: 6:45pm MDT
Moonrise: 6:18pm MDT
Difference: 27 minutes (Pass just barely, Moon and Sun are opposite)
September 30 The Moon rises within 30 minutes of sunset
Sunset: 6:44pm MST
Moonrise: 6:48pm MDT
Difference: 4 minutes (Pass Moon and Sun are opposite)
October 1 The Moon rises well after sunset
Sunset: 6:42pm MST
Moonrise: 7:20pm MDT
Difference: 38 minutes (Failed Moon and Sun are not opposite)
This test works “most” every time for any full looking moon. We here in Aurora have two evenings this month where the moonrise is within 30 minutes of sunset, one before sunset one after sunset. Not the usual pattern.
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.
September 29 and September 30 moonsets over the mountains in the predawn hours will be spectacular. The September 29 moonset (6:28am MDT) will occur just before sunrise (6:53am MDT). The September 30 moonset (7:28am MDT) occurs after sunrise (6:54am MDT). You want to start watching before 6:00 am MDT and 7:00pm MDT respectfully. If you have the time, observe the sunrise. They are usually pretty good here in Colorado.
If you happen to be a bicycle rider you may was to try the New Harvest Moon Triathlon Bike Course near Aurora, CO by the light of the harvest moon. Note also Aurora will be hosting Harvest Moon Triathlon Race and Festival on September 9.
Wishing you clear skies