This month’s full moon is commonly known as the Wolf Moon. Lesser known but equally appropriate names include Old Moon, Moon after the Yule, Ice Moon, Snow Moon, Hunger Moon, Cold Moon, and the Moon of the Terrible (Sioux). The Lakota Sioux called it “The Moon of Frost in the Teepee”. The Kalamath called it “The Moon of Little Finger’s Partner”.
You may notice this month’s full moon looks little smaller than usual. This month the full moon is also a “mini-moon” or “micro-moon”. That is to say it will be the smallest full moon we can see. It is the opposite of a “super-moon” which is the largest full moon we can see. Astronomically it is a happy coincidence. When the full moon is the furthest distance from Earth (apogee) it’s mini-moon, the shortest distance from Earth (perigee) it’s super-moon. Practically it means the Moon will appear 16% smaller and 30 times dimmer than a super-moon. Truth be told, “mini-moons” and “super-moons” happen every month, just not at the full moon phase.
Technically the full moon is only a moment in time. That moment occurs at 9:53PM MST on January 15. The Moon will look full on the evenings January 14, 15, and 16. That bright star next to the Moon on January 14 and 15 is Jupiter.
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.
Sunset: 4.57PM MST
Moonrise: 4:06PM MST
Difference: 51 minutes (Failed, Moon and Sun are not opposite)
Sunset: 4:58PM MST
Moonrise: 4.59PM MST
Difference: 1 minute (Pass, Moon and Sun are opposite, cannot get much closer)
Sunset: 4.59PM MST
Moonrise: 5:54PM MST
Difference: 55 minutes (Failed, Moon and Sun are not opposite)
This test works pretty much every time for any full looking Moon. This month the test is spot on because the full moon (9:53PM) occurs so close to local sunset (4:49PM), about 5 hours difference. When the Moon is opposite the Sun in the evening or morning it’s a full moon. This is a good time and month to take notice.
A full moon is the only time the Moon is up all night and the only time a lunar eclipse can take place as will happen in April and October this year. Full moons also set in the west opposite the rising sun. Living near the front range, as we do, provides neat moonsets over the mountains, easily noticed by early morning west-bound commuters.
On January 16 moonset (7:13AM MST) will occur a few minutes before sunrise (7:18AM MST). You want to start watching before 6:30AM MST. If you have the time, observe the sunrise. They are usually pretty good here in Colorado.
Wishing you clear skies