By Deborah Byrd in
Tonight | Moon Phases on Oct 05, 2013
Understanding moon phases
Photo Credit: Dan Bush
Why does the moon seem to change its shape every night? Remember that the moon is a world in space – with a day side and a night side.
Why does the moon seem to change its shape every night?
The answer is the moon is a world in space, just as Earth is. Like Earth, it’s always half illuminated by the sun. In other words, the round globe of the moon has a day side and a night side.
From our earthly vantage point, as the moon orbits around Earth, we see varying fractions of its day and night sides. These are the changing phases of the moon.
As the moon orbits Earth, it changes phase in an orderly way. Follow these links to understand the various phases of the moon.
Photo credit: Glass House
… and here are the names of all the full moons.
The primary key to understanding moon phases is to think about the whereabouts of the sun. After all, it’s the sun that’s illuminating and creating the day side of the moon.
Moon phases depend on the sun. They depend on where the moon is with respect to the sun in space.
Another key to understanding moon phases is to remember that, like the sun and all the planets and stars, the moon rises in the east and sets in the west each and every day.
It has to. The rising and setting of all celestial objects is due to Earth’s continuous spin beneath the sky.
Also, remember that the moon takes about a month (one “month”) to orbit the Earth. Although the moon rises in the east and sets in the west each day (due to Earth’s spin),
it’s also moving on the sky’s dome each day due to its own motion in orbit around Earth. The moon’s orbital motion can be detected in front of the stars from one night to the next. It’s as
though the moon is moving on the inside of a circle of 360 degrees. Thus the moon moves about 12 degrees each day.
And remember that the moon’s orbital motion is toward the east. Each day, as the moon moves another 12 degrees toward the east on the sky’s dome, Earth has to rotate a little
longer to bring you around to where the moon is in space. Thus the moon rises, on average, about 50 minutes later each day. The later and later rising time of the moon causes our companion
world to appear in a different part of the sky at each nightfall for about two weeks. Then, in the couple of weeks after full moon, you’ll find the moon rising later and later at night.
A composite of various moon phases by EarthSky Facebook friend Jacob Baker. He wrote: “This is a composite of 8 separate photos
taken over the past summer showing some various phases. All shots taken with my Meade 114mm reflector, 2X Barlow, CanonT3 at Prime Focus.”
Bottom line: This post explains why the moon waxes and wanes in phase, and gives some keys to understanding moon phases. It also provides links to descriptions of the various phases of the
MORE FROM EARTH SKY
Understanding full moon
Best photos of Venus and Saturn after sunset
Comet ISON’s path across our sky
December 2013 guide to the five visible
Everything you need to know: Geminid meteor shower
By EarthSky in
Tonight | Astronomy Essentials on Dec 16, 2013
Can you tell me the full moon names?
January 2013 full moon via Rick Trommater
For both the Northern and Southern Hemispheres, the full moons have names corresponding to the calendar months or the seasons of the year.
Some almanacs like to give each month a special full moon name. Other almanacs like to reference full moons relative to seasonal markers, as defined by equinoxes and solstices. Is one way
better than the other? No. Both have their roots in folklore. Of course, both the monthly names and the seasonal names necessarily favor either the Northern or Southern Hemisphere. That’s
because the moon has different characteristics in the two hemispheres, at opposite times of year. For example, the Harvest Moon is the full moon closest to the autumnal equinox. So it falls
in September or October for the Northern Hemisphere, and it falls in March or April for the Southern Hemisphere.
Here we list common full moon names – first by month (Northern and Southern Hemisphere) – and then by season (works for both hemispheres).
Photo by EarthSky Facebook friend Janet Wilson Fenn
Full moon via EarthSky Facebook friend Lee Capps
Northern Hemisphere full moon names by month:
January: Old Moon, Moon After Yule
February: Snow Moon, Hunger Moon, Wolf Moon
March: Sap Moon, Crow Moon, Lenten Moon
April: Grass Moon, Egg Moon
May: Planting Moon, Milk Moon
June: Rose Moon, Flower Moon, Strawberry Moon
July: Thunder Moon, Hay Moon
August: Green Corn Moon, Grain Moon
September: Fruit Moon, Harvest Moon
October: Harvest Moon, Hunter’s Moon
November: Hunter’s Moon, Frosty Moon, or Beaver Moon
December: Moon Before Yule, or Long Night Moon
Southern Hemisphere full moon names by month:
January: Hay Moon, Buck Moon, Thunder Moon, Mead Moon
February (mid-summer): Grain Moon, Sturgeon Moon, Red Moon, Wyrt Moon, Corn Moon, Dog Moon, Barley Moon
March: Harvest Moon, Corn Moon
April: Harvest Moon, Hunter’s Moon, Blood Moon
May: Hunter’s Moon, Beaver Moon, Frost Moon
June: Oak Moon, Cold Moon, Long Night’s Moon
July: Wolf Moon, Old Moon, Ice Moon
August: Snow Moon, Storm Moon, Hunger Moon, Wolf Moon
September: Worm Moon, Lenten Moon, Crow Moon, Sugar Moon, Chaste Moon, Sap Moon
October: Egg Moon, Fish Moon, Seed Moon, Pink Moon, Waking Moon
November: Corn Moon, Milk Moon, Flower Moon, Hare Moon
December: Strawberry Moon, Honey Moon, Rose Moon
About once every 19 years, February has no full moon at all.
Moreover, in 7 out of every 19 years, two full moons will fall in the same calendar month. The second of the month’s two full moons is popularly referred to as a Blue Moon. The next Blue Moon
by this definition will happen on July 31, 2015.
January 2013 full moon from EarthSky Facebook friend Fernando Alvarenga in San Salvador.
Full moon via Flickr user Ava Verino
Full moon names by season (Northern or Southern Hemisphere):
After the winter solstice:
Old Moon, or Moon After Yule
Snow Moon, Hunger Moon, or Wolf Moon
Sap Moon, Crow Moon or Lenten Moon
After the spring equinox:
Grass Moon, or Egg Moon
Planting Moon, or Milk Moon
Rose Moon, Flower Moon, or Strawberry Moon
After the summer solstice:
Thunder Moon, or Hay Moon
Green Corn Moon, or Grain Moon
Fruit Moon, or Harvest Moon
After the autumnal equinox:
Harvest Moon, or Hunter’s Moon
Hunter’s Moon, Frosty Moon, or Beaver Moon
Moon Before Yule, or Long Night Moon
There are usually three full moons in between an equinox and a solstice, or vice versa. Seven times in 19 years, four full moons fall in a single season. In that case, the
third of a season’s four full moons is also called a Blue Moon. The next Blue Moon by this definition will happen on August 21, 2013.
Full moon via Michelle Eve Photography
Photo via EarthSky Facebook friend Patricia Smith Mims
Bottom line: Northern and Southern Hemisphere full moon names, listed first by month and then by season.
Smallest full moon of 2013 on night of December 16-17
Tonight for December 16, 2013
Courtesy U.S. Naval Observatory
Your calendar probably says tomorrow (Tuesday, December 17) is the date for the last – and smallest – full moon of 2013. But, for North America, the full moon comes before sunrise tomorrow. So, for us, the moon turns full tonight. Need the exact time of full moon? It’s Tuesday,
December 17 at 9:28 Universal Time (4:28 a.m. EST, 3:28 a.m. CST, 2:28 a.m. MST and
1:28 a.m. PST). Tonight, the moon shines in front of the constellation Taurus the Bull, in the vicinity of the Bull’s brightest star, Aldebaran.
Quite the opposite of a supermoon, tonight’s full moon ranks as the smallest full moon of the 2013. However, next month’s January 2014 full moon will be even smaller than the December 2013 full
moon, to showcase the smallest full moon of 2014.
What is a supermoon?
Day and night sides of Earth at instant of full moon
Day and night sides of Earth at instant of December full moon (2013 December 17 at 9:28 Universal Time)
As always, the moon moves eastward in front of the backdrop stars (and planets) as its orbits our planet Earth. That eastward motion will bring the moon closer to the bright planet Jupiter on
the evening of December 17 and, closer yet to the king planet on the evening of December 18. Watch for Jupiter to rise in the east at nightfall or early evening
tonight and throughout December 2013.
Because this is the closest full moon to the December solstice, this moon carries the name Long Night Moon. That name works for the Northern Hemisphere, where the daylight is fleeting
now, while the nighttime is long-lasting. In the Southern Hemisphere – where the days are long and the nights are short – perhaps we could call the closest full moon to the December solstice
the Short Night Moon.
The full moon – as always – mimics the sun’s path for some six months hence. Watch tonight as the moon rises around sunset and sets around sunrise tomorrow. Around midnight, the moon climbs
highest up for the night, mimicking the position of the June noonday sun.
Given clear skies, most everyone all around the world will see the moon shining from dusk until dawn tonight. In the Northern Hemisphere, the moon’s path across the sky tonight will resemble
that of the high-flying summer sun. In the Southern Hemisphere, the moon’s path will follow the low arc of the winter sun.
Somewhat north of the Arctic Circle, there is no sunrise right now because the sun stays below the horizon. But the closest full moon to the December solstice stays out all night long at these
far northern latitudes, playacting as the midnight sun of summer.
Somewhat south of the Antarctic Circle, the sun stays out for 24 hours around the clock. However, the closest full moon to the December solstice simulates the winter sun in the Southern
Hemisphere. For that reason, this December full moon won’t rise above the horizon at these far southern latitudes.
The Winter Circle as seen from the Northern Hemisphere in 2012, when Jupiter was near the star Aldebaran. In 2013, Jupiter shines rather close to the Gemini stars, Castor and Pollux.
Winter Circle: Brightest Winter Stars
By the way, tonight’s bright and round moon shines right in front of the great big star formation known as the Winter Circle. In the Southern Hemisphere, though, it should really be
called the Summer Circle. Either way, tonight’s moon shows you where the sun will reside in front of the background stars six months from now.
The Winter Circle as seen from the Southern Hemisphere a year ago, in 2012. All will be pretty much the same tonight, except that Jupiter will be close to the stars Castor and Pollux, not the
Watch tonight, as the Northern Hemisphere’s Long Night Moon (Southern Hemisphere’s Short Night Moon) lights up the nighttime from dusk till dawn!
MORE FROM EARTH SKY
What is a supermoon?
December 2013 guide to the five visible
EarthSky’s meteor shower guide for 2013
Moon, Jupiter climb into sky at early evening on December
How to see Comet Lovejoy in
Oui, il y a tant de beauté.... Cette vision me transporte et vient nourrir jusqu'à la plus infime de mes cellules; comme si elle savaient, reconnaissaient et se gorgeaient d'une énergie puissante
Oui, il suffit de la regarder, toute cette beauté offerte et réconciliante....
C'est mon resenti, je sais qu'il peut sembler bien romantique mais ce n'est pas le cas. Les astres sont puissants, oui ils nous inspirent et nous font rêver mais ils transmettent aussi de façon
instantannée et extrêmement puissante...
Et dès lors, qu'Ils veillent sur nous avec bienveillance, tolérance et Amour...
Belle journée et gros bisous
Hier soir, j'ai eu le coucher du Soleil plus cette vision féerique.... D'où les rêves?....
Merci pimpim Soleil,
Grâce a toi, je peux la voir, les voir. Superbe. Merci.
Qui c'est qui as mis les grands sapins? Vais me fâcher! :)
Grosses bises, Léa.
Je l'ai vu en rentrant, hier soir.... Magnifique. Je voulais partager ce pur bonheur.... Bisous.