The traditional full moon name for October is the “Cold Moon”. It is also called the “Hunter’s Moon” when it is the first full moon after the fall equinox and the “Harvest Moon”. The “Harvest Moon” is some what unique in that the name is assigned to the full moon closest to the autumn equinox. This means the “Harvest Moon” can happen in October or September.
Other names include the "Blood Moon", or "Sanguine Moon". To the Natchez it’s the “Turkey Moon”. The Oglala Sioux called it the “Moon of the Changing Season”. The Cheyenne named it “The Moon when Water Freezes at the Edge of the Stream”. The Taos call it “The Corn Ripe Moon” and the Oto call it “Deer Rutting Season Moon”.
Technically the full moon is only a moment in time. For October that moment occurs at 5:39pm MDT on Friday, October 18. The Moon will look full on the evenings October 17, October 18, and October 19. So which is closest to the true full moon? There is an easy way for the casual observer to tell. 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.
October 17 The Moon rises well before sunset
Sunset: 6:18pm MDT
Moonrise: 5:32pm MDT
Difference: 46 minutes (Failed, Moon and Sun are not opposite)
October 18 The Moon rises within 30 minutes of sunset
Sunset: 6:16pm MDT
Moonrise: 6:07pm MDT
Difference: 9 minutes (Pass, Moon and Sun are opposite)
October 19 The Moon rises well after sunset
Sunset: 6:15pm MST
Moonrise: 6:44 pm MDT
Difference: 31 minutes (Failed, just barely, Moon and Sun are not opposite)
This test works “most” every time for any full looking moon. The rule occasionally falls apart if the time of the full moon is close to local sunrise or sunset time. This month the full Moon occurred close to local sunset time. Note how close the full moon test was missed (one minute) on October 19.
A full moon is the only time the Moon is up all night and the only time a lunar eclipse can take place. 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 October 19 moonset (7:54am MDT) will occur a few minutes before sunrise (7:13am MDT).You want to start watching around 6:45am MDT. If you have the time, observe the sunrise. They are usually pretty good here in Colorado.
Wishing you clear skies