The moon will be 100 percent full at 2:40 p.m. EDT (1840 GMT). If you're in the continental U.S., you won't be able to see the moon, as it will be below the horizon at that time. However, the moon will still look pretty full after it rises that evening. Check out our latest story here .
It will make a close pass by Neptune, just as the full moon did in September, though you'll need binoculars or a telescope to see the distant planet. On Oct. 3, South Pacific observers in Tasmania, New Zealand and southeastern Australia will see the 94 percent-illuminated moon occult, or pass in front of, Neptune. [A Planet Skywatching Guide for 2017]
Situated in the constellation Aquarius, the (almost) full moon will rise on Thursday evening (Oct. 5) at 6:51 p.m. EDT in New York City, setting the next morning at 7:40 a.m., according to timeanddate.com.
Neptune greets the Harvest Moon
Neptune's occultation won't be visible from the United States; only skywatchers in New Zealand, Tasmania and the area east of Melbourne, Australia, will see the moon pass in front of the planet. For observers in Christchurch, New Zealand, the occultation will start (with Neptune disappearing behind the moon) at 1:26 a.m. Oct. 4, and ends at 2:39 a.m. In Australia, the city of East Sale will see the occultation start at 11:18 p.m., with Neptune reappearing at 11:46 p.m. In Tasmania, the city of Hobart will begin at 10:58 p.m. and end at 11:55 p.m.
For viewers along the U.S. East Coast, the moon will have already set below the horizon before the occultation. Stargazers on the West Coast can watch the moon pass closely by Neptune shortly before 4 a.m. PDT, just about 30 minutes before the moon sets.
Neptune isn't visible without at least a good pair of binoculars, and preferably a small telescope. Bright light from the full moon will wash out fainter stars around the natural satellite. However, the proximity between Neptune and the moon may make the planet somewhat easier to locate in the sky. Neptune's maximum brightness is about magnitude 7.8, fainter than what an observer with good vision can see even from a dark-sky site.
Planets on parade
On the night of the full moon, other planets will accompany our planet's natural satellite as it rises into the sky. Uranus will rise just ahead of the moon at around 7 p.m. local time, though it will be easier to see as it rises higher above the horizon closer to midnight. Uranus is not easily visible without binoculars, though it can be seen in the darkest skies on clear nights.
West of the moon, Saturn will be in the constellation Ophiuchus and will set at about 10 p.m. local time, just as the full moon gets high enough in the sky to clear most buildings. Jupiter will be setting shortly after the moon rises.
To find out precisely when each planet will be visible from your location, check out timeanddate.com's night-sky calculator. You can also find out exactly when the moon will rise and set using that site's moon calculator.
An unusual Harvest Moon
According to the Old Farmer's Almanac, the name of the full moon in October is usually "Hunter's Moon," as October is when people would hunt to store food for winter. However, this year is a bit out of the ordinary, and we'll have a Harvest Moon instead.
The Harvest Moon is defined as the full moon that falls closest to the autumn equinox, which happened on Sept. 22. Usually September's full moon is called the Harvest Moon, but this year, it just so happened that October's full moon is closer to the equinox. So, September's full moon was named the "Corn Moon" instead, and the next Hunter's Moon won't happen until October 2018.
Native people in North America had several different associations and names for the full moons. According to the Ontario Native Literacy Coalition, the Ojibwe peoples called October's full moon the Mskawji Giizis, or the Freezing Moon, as the weather changes and first frosts occur at this time. Cree people called it Pimahamowipisim, or the Migrating Moon, as in northeastern North America, many bird species start migrating south for the winter in October. In the Pacific Northwest, the Tlingit called the lunation of October the Big Moon, while the Haida called the month the Ice Moon.
In the Southern Hemisphere, the days are getting warmer and longer in October. The Māori of New Zealand described the lunar months in September to October as Whiringa-ā-nuku, which means, "The Earth has now become quite warm," according to "The Encyclopedia of New Zealand."
The full moon of October also marks an important holiday for Jewish people: Sukkot, the 15th day of the month of Tishrei. The holiday is also known as the Feast of Tabernacles, and is a celebration of the harvest and the exodus from Egypt.