The next full Moon will be on Wednesday morning, October 20, 2021, appearing opposite the Sun (in Earth-based longitude) at 10:57 a.m. EDT. This will be on Wednesday for much of the world but will be on Thursday from Australian Central Standard time eastward to the International Date Line. The Moon will appear full for about three days around this time, from Monday night into Thursday night.
As the full Moon after the Harvest Moon, this will be the Hunter’s Moon. The earliest use of the term “Hunter’s Moon” cited in the Oxford English Dictionary is from 1710. According to the Farmer’s Almanac, with the leaves falling and the deer fattened, it is time to hunt. Since the harvesters have reaped the fields, hunters can easily see the animals that have come out to glean (and the foxes that have come out to prey on them).
The Maine Farmer’s Almanac first published Native American names for the full Moons in the 1930s. Over time, these names have become widely known and used. According to this almanac, as the full Moon in October the Algonquin tribes in what is now the northeastern U.S. called this the Travel Moon, the Dying Grass Moon, or the Sanguine or Blood Moon. Some sources indicate that the Dying Grass, Sanguine, and Blood Moon names are related to the turning of the leaves and dying back of plants with the start of fall. Others indicate that the names Sanguine or Blood Moon are associated with hunting to prepare for winter.
I have read that the name Travel Moon comes from observing the migration of birds and other animals preparing for the winter. I don’t know, but this name may also refer to the season when the more northern tribes would move down from the mountains for the winter. For example, both the Iroquois and Algonquin would hunt in the Adirondacks in the summertime but would leave to avoid the harsh mountain winter.
This full Moon occurs around the end of the seasonal monsoon rains in the Indian subcontinent. It marks the end of the month of Ashvin in the traditional Hindu calendar and Thadingyut in the traditional Burmese calendar.
For Hindus, this is Sharad Purnima, a harvest festival celebrated in a variety of ways throughout India.
For Buddhists, this Moon marks the end of Vassa, the three-month period of fasting for Buddhist monks tied to the monsoons (Vassa is sometimes given the English names Rains Retreat or Buddhist Lent). There are numerous festivals and holy days associated with this Moon at the end of Vassa. Many Buddhists observe the holy day Pavarana on this day. In Myanmar, this full Moon corresponds with the three-day Thadingyut Festival of Lights, also known as the Lighting Festival of Myanmar. Also in Myanmar, this full Moon is near the end of the Phaung Daw Oo Pagoda Festival. This festival began on the first Waxing Moon day of the month of Thadingyut (October 6, 2021) and will end a few days past the full Moon (October 23). In Laos, this full Moon corresponds with Boun Suang Huea or the Boat Racing Festival.
Jupiter is the largest planet in our solar system with 2.5 times the mass of all the other planets combined. As our solar system formed over four billion years ago, Jupiter’s gravity created two stable locations ahead of and behind Jupiter in its orbit. The asteroids in these locations appear to have been there since the birth of our solar system and are expected to yield vital clues to deciphering its history. They may even tell us about the kinds of organic materials that may have been supplied to the early Earth. Lucy will spend 12 years exploring seven of these asteroids, plus one main belt asteroid that Lucy will encounter on its way.
The Moon’s Connection to Calendars
In most lunisolar calendars the months change with the new Moon and full Moons fall near the middle of the lunar months. This full Moon is near the middle of the ninth month of the Chinese calendar, Marcheshvan (often shortened to Cheshvan or Heshvan) in the Hebrew calendar, and Rabi? al-Awwal in the Islamic calendar.
As usual, the wearing of suitably celebratory celestial attire is encouraged in honor of the full Moon.
Here is a summary of other celestial events between now and the full Moon after next (with times and angles based on the location of NASA Headquarters in Washington):
As autumn continues the daily periods of sunlight continue to shorten. On Wednesday, October 20, (the day of the full Moon), morning twilight will begin at 6:25 a.m. EDT, sunrise will be at 7:23 a.m., solar noon will be at 12:52:45 p.m. when the Sun will reach its maximum altitude of 40.55 degrees, sunset will be at 6:22 p.m., and evening twilight will end at 7:20 p.m.
Daylight Saving Time Ends
Ever since 2007 when Congress moved the start of Daylight Saving Time from the end of October to the beginning of November, the latest sunrises of the year have been in late October and early November. In 2021 (for the Washington, D.C. area) the sunrises from October 24 to November 6 (in EDT) will be later than were the latest sunrises of winter on January 4 and 5, 2021 (which were at 7:27 a.m. EST). If you find you are having trouble waking up in late October and early November, these dark mornings may be the reason (or at least a reasonable excuse).
The latest sunrise of the year will be on Saturday, November 6, the last day of Daylight Saving Time. Morning twilight will begin at 6:41 a.m. EDT, sunrise will be at 7:41 a.m., solar noon will be at 12:51:40 p.m. when the Sun will reach its maximum altitude of 34.95 degrees, sunset will be at 6:02 p.m., and evening twilight will end at 7:02 p.m.
On Sunday, November 7, 2021, we “fall back” from 2 a.m. EDT to 1 a.m. EST, gaining an hour of sleep. Morning twilight on November 7 will begin at 5:42 a.m. EST, sunrise will be at 6:42 a.m., solar noon will be at 11:51:43 a.m. when the Sun will reach its maximum altitude of 34.66 degrees, sunset will be at 5:01 p.m., and evening twilight will end at 6:01 p.m.
By Friday, November 19 (the day of the full Moon after next), morning twilight will begin at 5:54 a.m. EST, sunrise will be at 6:55 a.m., solar noon will be at 11:53:32 p.m. when the Sun will reach its maximum altitude of 31.52 degrees, sunset will be at 4:51 p.m., and evening twilight will end at 5:53 p.m.
Planets and Meteors
These should still be good evenings for Jupiter and Saturn watching, especially with a backyard telescope. Both Saturn and Jupiter were at their closest and brightest for the year in August. While dimming as they shift farther from Earth, they are still relatively bright. Both have been shifting west, making them easier to view in the evenings (and friendlier for backyard stargazing, especially if you have young ones with earlier bedtimes). With clear skies and a telescope, you should be able to see Jupiter’s four bright moons, Ganymede, Callisto, Europa, and Io, noticeably shifting positions in the course of an evening. For Saturn, you should be able to see Saturn’s rings as well as Saturn’s largest moon, Titan.
2021 will not be a good year for seeing the Orionid Meteor Shower due to interference from the full Moon. This shower is expected to be active from October 2 to November 7, 2021, with a peak on the morning of October 21, the day after the full Moon.
Evening Sky Summary
On the evening of Wednesday, October 20, 2021, (the day of the full Moon), as evening twilight ends (at 7:20 p.m. EDT), the brightest planet visible will be Venus, appearing 10 degrees above the southwestern horizon. The next brightest planet will be Jupiter, appearing 32 degrees above the south-southeastern horizon. The faintest of the visible planets in the sky will be Saturn, appearing 31 degrees above the southern horizon. The bright star closest to overhead will be Deneb, appearing 81 degrees above the northeastern horizon. Deneb is about 2,600 light-years from Earth and is the 19th brightest star in our night sky.
As the lunar cycle progresses, Jupiter, Saturn, and the background of stars will appear to shift toward the west each evening (although it is actually the Earth that is moving around the Sun toward the east). The bright planet Venus will appear to shift left along the southwestern horizon each evening, appearing brighter and higher above the horizon as it shifts closer to the Earth. The waxing Moon will appear to pass near Venus on November 7, Saturn on November 10, and Jupiter on November 11, 2021.
By the evening of Friday, November 19, 2021, (the day of the full Moon after next), as evening twilight ends (at 5:53 p.m. EST), the brightest planet visible will be Venus, appearing 14 degrees above the southwestern horizon. The next brightest planet will be Jupiter, appearing 37 degrees above the southern horizon. The faintest of the visible planets in the sky will be Saturn, appearing to the right of Jupiter at 31 degrees above the south-southwestern horizon. The bright star closest to overhead still will be Deneb, appearing 77 degrees above the northwestern horizon. The bright star Aldebaran will just be rising, appearing about 8 degrees below the full Moon on the east-northeastern horizon.
Morning Sky Summary
On the morning of October 20, 2021 (the day of the full Moon), as morning twilight begins (at 6:25 a.m. EDT), the only visible planet in the sky will be Mercury, appearing about 5 degrees above the eastern horizon. The bright stars of the local arm of our home galaxy, including the constellation Orion, will appear spread across the sky from the south-southeast toward the west-northwest. The bright star appearing closest to directly overhead will be Pollux at 77 degrees above the southeastern horizon. Pollux is the brighter of the twins in the constellation Gemini and is about 34 light-years from us.
As the lunar cycle progresses the background of stars will appear to shift toward the west. The planet Mercury will appear at its highest above the horizon for this appearance on October 25, 2021, after which it will begin shifting back toward the horizon.
The waning Moon will pass near the bright star Aldebaran on October 24, Pollux on October 27 and 28, and Regulus on October 30, 2021. On the morning of October 30, the bright star Spica will begin appearing above the horizon at the time morning twilight begins, appearing to the lower right of Mercury. Mercury and Spica will appear at their closest on the morning of November 2, with Spica appearing 3 degrees to the right of Mercury. The next morning, November 3, the waning crescent Moon will join Mercury and Spica to form a triangle on the east-southeastern horizon. November 10 will be the first morning that Mercury will no longer be above the horizon as morning twilight begins, but if you have a clear view of the east-southeastern horizon, you should be able to see the fainter planet Mars appearing just a degree to the right of Mercury after morning twilight begins but before the sky becomes too bright to see Mars.
Beginning November 13, the planet Mars will begin appearing above the east-southeastern horizon as morning twilight begins. Mercury should be bright enough that you may still be able to see it in the glow of dawn after it rises until around November 18.
By the morning of November 19, 2021 (the day of the full Moon after next), as morning twilight begins (at 6:25 a.m. EST), the only visible planet in the sky will be Mars, appearing just a degree above the east-southeastern horizon. The bright stars of the local arm of our home galaxy will appear spread across the southwestern horizon. The bright star appearing closest to directly overhead still will be Pollux at 64 degrees above the west-southwestern horizon, with Regulus a close second at 62 degrees above the south-southeastern horizon. Regulus appears to us as one star (the 21st brightest star in our sky), but it is actually two pairs of stars orbiting each other for a total of four stars. Regulus is 79 light-years from us.