Arrow displaying position of the batholith on the farside of the Moon (left) with the heat gradient from the granite within the Compton-Belkovich Thorium Anomaly (center and right). (Credit: Matthew Siegler, PSI)
A recent study published in Nature examines a volcanic hotspot that potentially exists beneath a feature on the Moon’s farside (the side facing away from the Earth) called the Compton-Belkovich Thorium Anomaly. Researchers led by the Planetary Science Institute collected data from the hotspot region using microwave instruments onboard the China National Space Administration’s Chang’e-1 and Chang’e-2 orbiters and holds the potential to help scientists better understand the past volcanic processes on our nearest celestial neighbor, as surface evidence indicates lunar volcanic activity ceased between 3 to 4 billion years ago.
Long exposure photo of the super blue moon, taken by Marc Leatham in Cypress, CA. Credit: Marc Leatham
On Wednesday, January 31st (i.e. today!), a spectacular celestial event occurred. For those who live in the western part of North America, Alaska, and the Hawaiian islands, it was visible in the wee hours of the morning – and some people were disciplined enough to roll out of bed to see it! This was none other than the highly-anticipated “Super Blue Moon“, a rare type of full moon that on this occasion was special for a number of reasons.
For one, it was the third in a series of “supermoons”, where a Full Moon coincides with the Moon being closer in its orbit to Earth (aka. perigee) and thus appears larger. It was also the second full moon of the month, which is otherwise known as a “Blue Moon“. Lastly, for those in right locations, the Moon also passed through the Earth’s shadow, giving it a reddish tint (known as a “Red Moon” or “Blood Moon”).
The super blue moon, taken by Kevin Gill in Los Angeles, CA, with a Canon EOS 60D mounted on a Celestron NexStar 6se. Credit: @apoapsys
In short, you could say that what was occurred this morning was a “super blue blood moon.” And as you can see, some truly awesome pictures were taken of this celestial event from all over the world. Here is a collection of pictures that a number of skilled photographers and star gazers have chosen to share with us. Enjoy!
A collage of images showing the transition of the super blue moon, taken by Braden Ottenbreit of Saskatchewan, Canada. Credit: @bradenottenbreit
Long exposure photo of the super blue moon, taken by Marc Leatham in Cypress, CA. Credit: @marcleatham
Early morning photo snapped outside of Pucklechurch, Bristol, by photographer Tim Graham. Credit: @timgrahamphotorgraphy
The lunar eclipse captured in Shiraz, Iran, by Alireza Nadimi using a Nikon D610A – Sigma 120-400 Apo. Credit: @ar.nadimi
The phases of the lunar eclipse of the Super Blue Blood Moon, taken by astrophographer Rami Ammoun. Credit: @rami_ammoun
Super blue moon taken by Bray Falls in Arizona. Credit: @astrofalls
The super blue moon, as photographed from Los Angeles by Tom Masterson using a Tamron 150-600mm and Canon 6D Hutech UV/IR mod. Credit: @transientastro
A long-exposure shot of the super blue moon above San Francisco by Taylor Meehan. Credit: @tm18210
Composite image showing the sequence of the eclipse, as seen from downtown Houston. Credit: @sergiorill
A composite of the phases of our super blue moon lunar eclipse. Credit: @jeffycan
“Thanks to everyone who used the #universetoday hashtag on Instagram to let us know about your pictures. There are many many more in there, so check it out.”
The waxing gibbous Moon closes in on Aldebaran (lower left). Image credit and copyright: Sarah & Simon Fisher
As you’ve probably noticed, the Moon looks different from one evening to the next. Sometimes we see a New Moon, when the Moon is enshrouded in shadow. At other times, we see a Full Moon, when the entire face of the Moon is illuminated. And of course, there are the many phases in between, where portions of the Moon are illuminated.
This is what is called a Lunar Cycle, a 29 ½-day period (aka. lunar month) where the Moon becomes brighter and dimmer, depending on its orientation with the Earth and the Sun. During the first half of a lunar month, when the amount of illumination on the Moon is increasing, astronomers call this a “waxing moon”.
Lunar Cycle:
To understand the Lunar Cycle, we first must consider the Moon’s orbit in relation to Earth. Basically, the Moon orbits Earth, and Earth orbits the Sun, which means the Moon is always half illuminated by the latter. But from our perspective here on Earth, which part of the Moon is illuminated – and how much – changes over time.
When the Sun, the Moon and Earth are perfectly lined up, the angle between the Sun and the Moon is 0-degrees. At this point, the side of the Moon facing the Sun is fully illuminated, and the side facing the Earth is enshrouded in darkness. We call this a New Moon.
After this, the phase of the Moon changes, because the angle between the Moon and the Sun is increasing from our perspective. A week after a New Moon, and the Moon and Sun are separated by 90-degrees, which effects what we will see. And then, when the Moon and Sun are on opposite sides of the Earth, they’re at 180-degrees – which corresponds to a Full Moon.
Waxing vs. Waning:
The period in which a Moon will go from a New Moon to a Full Moon and back again is known as “Lunar Month”. One of these lasts 28 days, and encompasses what are known as “waxing” and “waning” Moons. During the former period, the Moon brightens and its angle relative to the Sun and Earth increases.
A waxing gibbous Moon from October 12th, headed towards Full this weekend. Image credit and copyright: John Brimacombe.
When the Moon is in between the Earth and the Sun, the side of the Moon facing away from the Earth is fully illuminated, and the side we can see is shrouded in darkness. As the Moon orbits the Earth, the angle between the Moon and the Sun increases. At this point, the angle between the Moon and Sun is 0 degrees, which gradually increases over the next two weeks. This is what astronomers call a waxing moon.
After the first week, the angle between the Moon and the Sun is 90-degrees and continues to increase to 180-degrees, when the Sun and Moon are on opposite sides of the Earth. When the Moon starts to decrease its angle again, going from 180-degrees back down to 0-degrees, astronomers say that it’s a waning moon. In other words, when the Moon is waning, it will have less and less illumination every night until it’s a New Moon.
Waxing Phases:
The period when the Moon is waxing occurs between a New Moon and a Full Moon, which is characterized by many changes in appearance. The first is known as a Waxing crescent, where 1-49% of the Moon is illuminated. Which side appears illuminated will depend on the observer’s location. For those living in the northern hemisphere, the right side will appear illuminated; whereas for those in the southern hemisphere, the reverse is the case.
Next up is the First Quarter, where 50% of the Moon’s face is illuminated – again, the right side for those in the northern hemisphere and the left for those in the south. This is followed by a Waxing Gibbous Moon, where 51 – 99% of the Moon’s surface is illuminated – right side in the northern hemisphere, left side in the southern. The waxing phase concludes with a Full Moon.
The Full Moon at 10:30 p.m. last night (Aug. 30). Even at 25 altitude, it glowed a deep, dark orange due to heavy smoke from western forest fires. Credit: Bob King
Did you see the Moon last night? I walked outside at 10:30 p.m. and was stunned to see a dark, burnt-orange Full Moon as if September’s eclipse had arrived a month early. Why? Heavy smoke from forest fires in Washington, California and Montana has now spread to cover nearly half the country in a smoky pall, soaking up starlight and muting the moonlight.
If this is what global warming has in store for us, skywatchers will soon have to take a forecast of “clear skies” with a huge grain of salt.
The Pacific Northwest is abundantly dotted with wildfires in Washington, Oregon, Idaho and Montana in this Aqua satellite image taken on August 25, 2015. Actively burning areas, detected by MODIS’s thermal bands, are outlined in red. Smoke from the fires has been drifting east, blanketing Midwestern skies and blotting out the stars at night. Credit: NASA image courtesy Jeff Schmaltz, MODIS Rapid Response Team
By day, the sky appears the palest of blues. By night, the stars are few if any, and the Moon appears faint, the color of fire and strangely remote. Despite last night’s clear skies, only the star Vega managed to penetrate the gloom. I never saw my shadow even at midnight when the Moon had climbed high into the southern sky.
Last night’s Full Moon seen through an 8-inch telescope at 11:30 p.m. The colors are true. Credit: Bob King
We’ve seen this smoke before. Back in July, Canadian forest fires wafted south and west and covered much of the northern half of the U.S., giving us red suns in the middle of the afternoon and leaving only enough stars to count with two hands at night. On the bright side, the Moon is fascinating to observe. I set up the telescope last night and spend a half hour watching this unexpected “eclipse”; sunsets appear positively atomic. The size of the smoke particles is just right for filtering out or scattering away blues, greens and even yellow from white light. Vivid reds, pinks and oranges remain to tint anything bright enough to penetrate the haze.
GOES-8 satellite view of the central U.S. taken at 8:15 a.m. CDT August 30, 2015 show a veil of grayish forest fire smoke covering much of the Midwest with clearer conditions to the southeast. The red line is the approximate border between the two. Credit: NOAA
But smoke can cause harm, too. Forest fire smoke contains carbon monoxide, carbon dioxide and soot. On especially smoky days, you can even smell the odor of burning trees in the air at ground level. Some may suffer from burning eyes, asthma or bronchitis on especially smoky days even a thousand miles from the source fires.
Wide-angle view of last night’s Moon. Notice that the smoke is thicker along the horizontal – left and right of the Moon. Above, at a higher elevation, we see through less smoke, so the moonlit sky is a bit brighter there. No stars are visible. Credit: Bob King
On clear, blue-sky days, I’ve watched the smoke creep in from the west. It begins a light haze and slowly covers the entire sky in a matter of several hours, often showing a banded structure in the direction of the Sun. A little smoke is OK for observing, but once it’s thick enough to redden the Moon even hours after moonrise, you can forget about using your telescope for stargazing. Sometimes, a passing thunderstorm and cold front clears the sky again. Sometimes not.
The only cures for fire soot are good old-fashioned rain and the colder weather that arrives with fall. In the meantime, many of us will spend our evenings reading about the stars instead of looking at them.
A Full Moon in all its horizontal glory. When near the horizon, refraction squeezes the lunar disk into an oval. Scattering removes the shorter wavelengths of white light, leaving the Moon a rich red or orange. Credit: Bob King
Who doesn’t love a Full Moon? Occurring about once a month, they never wear out their welcome. Each one becomes a special event to anticipate. In the summer months, when the Moon rises through the sultry haze, atmosphere and aerosols scatter away so much blue light and green light from its disk, the Moon glows an enticing orange or red.
At Full Moon, we’re also more likely to notice how the denser atmosphere near the horizon squeezes the lunar disk into a crazy hamburger bun shape. It’s caused by atmospheric refraction. Air closest to the horizon refracts more strongly than air near the top edge of the Moon, in effect “lifting” the bottom of the Moon up into the top. Squished light! We also get to see all the nearside maria or “seas” at full phase, while rayed craters like Tycho and Copernicus come into their full glory, looking for all the world like giant spatters of white paint even to the naked eye.
At full phase, the Moon lies directly opposite the Sun on the other side of Earth. Sunlight hits the Moon square on and fully illuminates the Earth-facing hemisphere. Credit: Bob King
Tomorrow night (August 29), the Full Sturgeon Moon rises around sunset across the world. The name comes from the association Great Lakes Indian groups made between the August moon and the best time to catch sturgeon. Next month’s moon is the familiar Harvest Moon; the additional light it provided at this important time of year allowed farmers to harvest into the night.
A Full Moon lies opposite the Sun in the sky exactly like a planet at opposition. Earth is stuck directly between the two orbs. As we look to the west to watch the Sun go down, the Moon creeps up at our back from the eastern horizon. Full Moon is the only time the Moon faces Sun directly – not off to one side or another – as seen from Earth, so the entire disk is illuminated.
The moon provides the perfect backdrop for watching birds migrate at night. Although a small telescope is best, you might see an occasional bird in binoculars, too. Credit: Bob King
If you’re a moonrise watcher like I am, you’ll want to find a place where you can see all the way down to the eastern horizon tomorrow night. You’ll also need the time of moonrise for your city and a pair of binoculars. Sure, you can watch a moonrise without optical aid perfectly well, but you’ll miss all the cool distortions happening across the lunar disk from air turbulence. Birds have also begun their annual migration south. Don’t be surprised if your glass also shows an occasional winged silhouette zipping over those lunar seas.
Because the Moon’s orbit is tilted 5.1° with respect to Earth’s, it normally passes above or below Earth’s shadow with no eclipse — either lunar or solar. Only when the lineup is exact, does the Moon pass directly behind Earth and into its shadow. Credit: Bob King
Next month’s Full Moon is very special. A few times a year, the alignment of Sun, Earth and Moon (in that order) is precise, and the Full Moon dives into Earth’s shadow in total eclipse. That will happen overnight Sunday night-Monday morning September 27-28. This will be the final in the current tetradof four total lunar eclipses, each spaced about six months apart from the other. I think this one will be the best of the bunch. Why?
The totally eclipsed moon on April 15, 2014 from Duluth, Minn. This was the first in the series of four eclipses called a tetrad. September’s totally eclipsed Moon will appear similar. The coloring comes from sunlight grazing the edge of Earth’s atmosphere and refracted by it into the planet’s shadow. Credit: Bob King
Convenient evening viewing hours (CDT times given) for observers in the Americas. Partial eclipse begins at 8:07 p.m., totality lasts from 9:11 – 10:23 p.m. and partial eclipse ends at 11:27 p.m. Those times mean that for many regions, kids can stay up and watch.
The Moon passes more centrally through Earth’s shadow than during the last total eclipse. That means a longer totality and possibly more striking color contrasts.
September’s will be the last total eclipse visible in the Americas until January 31, 2018. Between now and then, there will be a total of four minor penumbral eclipses and one small partial. Slim pickings.
Diagram showing the details of the upcoming total lunar eclipse. The event begins when the Moon treads into Earth’s outer shadow (penumbra) at 7:12 p.m. CDT. Partial phases start at 8:07 and totality at 9:11. Credit: NASA / Fred Espenak
Not only will the Americas enjoy a spectacle, but totality will also be visible from Europe, Africa and parts of Asia. For eastern hemisphere skywatchers, the event will occur during early morning hours of September 28. Universal or UT times for the eclipse are as follows: Partial phase begin at 1:07 a.m., totality from 2:11 – 3:23 a.m. with the end of partial phase at 4:27 a.m.
September 27-28, 2015 eclipse visibility map. Credit: NASA / Fred Espenak
We’ll have much more coverage on the upcoming eclipse in future articles here at Universe Today. I hope this brief look will serve to whet your appetite and help you anticipate what promises to be one of the best astronomical events of 2015.
A full moon in October is known as a "Hunters Moon". Credit: David Haworth/stargazing.net
If you live in the northern hemisphere, than stargazing during the early autumn months can a bit tricky. During certain times in these seasons, the stars, planets and Milky Way will be obscured by the presence of some very beautiful full moons. But if you’re a fan of moongazing, then you’re in luck.
Because it is also around this time (the month of October) that people looking to the night sky will have the chance to see what is known as a Hunter’s Moon. A slight variation on a full moon, the Hunter’s Moon has long been regarded as a significant event in traditional folklore, and a subject of interest for astronomers.
Definition:
Also known as a sanguine or “blood” moon, the term “Hunters Moon” is used traditionally to refer to a full moon that appears during the month of October. It is preceded by the appearance of a “Harvest Moon”, which is the full moon closest to the autumnal equinox (which falls on the 22nd or 23rd of September).
The Hunter’s Moon typically appears in October, except once every four years when it doesn’t appear until November. The name dates back to the First Nations of North America. It is so-called because it was during the month of October, when the deers had fatted themselves over the course of the summer, that hunters tracked and killed prey by autumn moonlight, stockpiling food for the coming winter.
Full Moon Rising Over Northwest Georgia on June 22nd, 2013. Credit and copyright: Stephen Rahn.
Characteristics:
Although typically the Moon rises 50 minutes later each day, things are different for the Hunter’s Moon (as well as the Harvest Moon). Both of these moons usually rise 30 minutes later on each successive night, which means that sunset and moonrise are not far apart.
This means there is prolonged periods of light during this time of the the year, which is the reason why these moons have traditionally been used by hunters and farmers to finish their work.
This difference between the timing of the sunset and moonrise is due to its orbit, meaning that the angle the Moon makes with the horizon is narrower during this time of year. The Hunter’s Moon is generally not bigger or brighter than any of the other full moons. Thus, the only difference between it and other full moons is the that the time between sunset and moonrise is shorter.
History of Observation:
Because the approach of winter signaled the possibility of going hungry in pre-Industrial times, the Hunter’s Moon was generally accorded with special honor, historically serving as an important feast day in both northern Europe and among many Native American tribes.
Traditionally, Native American hunters used the full moon of October to stalk deer and to spot foxes at night as they prepared for the coming winter. Because the fields were traditionally reaped in late September or early October, hunters could easily see foxes and other animals that came out to glean from the fallen grains.
The Hunter’s Moon is accorded similar significance in Europe, where it was also seen as a prime time to hunt during the post-harvest, pre-winter period when conditions were optimal for spotting prey. However, the term did not enter into usage for Europeans until after they made contact with Indigenous Americans and began colonizing North America.
The first recorded mentions of a “Hunter’s Moon” began in the early 18th century. The entry in the Oxford English Dictionary for “Hunter’s Moon” cites a 1710 edition of The British Apollo, where the term is attributed to “the country people”. The names are now referred to regularly by American sources, where they are often popularly attributed to “the Native Americans”.
In India, the harvest festival of Sharad Purnima, which marks the end of the monsoon season, is celebrated on the full moon day of the lunar month of Ashvin (September-October). There is a traditional celebration of the moon during this time that is known as the “Kaumudi” celebration – which translated, means “moonlight”.
The harvest festival of Shrad Purnima is celebrated on the full moon day of the Hindu lunar month of Ashvin. Credit: dfwhindutemple.org
Interesting Facts:
Sometimes, the Harvest Moon is mistaken for the Hunter’s Moon because once every four years or so the Harvest Moon is in October instead of September. When that happens, the Hunter’s Moon is in November. Traditionally, each month’s full moon has been given a name, although these names differ according to the source.
Other full moons of interest include the Wolf Moon in January, the Strawberry Moon in June, the Sturgeon Moon in August, the Cold Moon in December, and the Pink Moon in April. All of the full moons have different characteristics due to the location of the ecliptic – i.e. the path of the Sun – at the time of each.
The Hunter’s Moon is also associated with feasting. In the Northern Hemisphere, some Native American tribes and some places in Western Europe held a feast day. This feast day, the Feast of the Hunter’s Moon, was not been held since the 1700’s. However, the Feast of the Hunters’ Moon is a yearly festival in Lafayette, Indiana, which has been held in late September or early October every year since 1968.
We have many interesting articles about the moon here at Universe Today. For example, here are some about the red moon and a rundown of what a full moon is all about.
A halo rings the bright moon and planet Jupiter (left of moon) Credit: Bob King
The Full Moon celebrates Jupiter’s coming opposition by accompanying the bright planet in a beautiful conjunction tonight.
Even last night Jupiter and the Moon were close enough to attract attention. Tonight they’ll be even more striking. Two reasons for that. The Moon is full this evening and will have crept within 41/2° of the planet. They’ll rise together and roll together all night long.
The Full Snow Moon will share the sky with Jupiter in Cancer tonight not far from the Sickle or head of Leo the Lion. The map shows the scene around 8 o’clock local time. Source: Stellarium
February’s full moon is aptly named the Full Snow Moon as snowfall can be heavy this month. Just ask the folks in Chicago. The Cherokee Indians called it the “Bone Moon”, named for the tough times experienced by many Native Americans in mid-winter when food supplies ran low. With little left to eat people made use of everything including bones and bone marrow for soup.
Not only is the Full Moon directly opposite the Sun in the sky, rising around sunset and setting around sunrise, but in mid-winter they’re nearly on opposite ends of the celestial seesaw.
Jupiter, like tonight’s Full Moon, will be directly opposite the Sun this Friday and in “full moon” phase. Because both planets are lined up on the same side of the Sun, Jupiter will also be at its closest to us for the year. Credit: Bob King
In early February the Sun is still near its lowest point in the sky (bottom of the seesaw) for the northern half of the globe. And while daylight is steadily increasing as the Sun moves northward, darkness still has the upper hand this month. Full Moons like tonight’s lie 180° opposite the Sun, placing the Moon near the top of the seesaw. Come early August, the Sun will occupy the Moon’s spot and the Full Moon will have slid down to the Sun’s current position. Yin and Yang folks.
Now here’s the interesting thing. Jupiter will also be in “full moon” phase when it reaches opposition this Friday Feb. 6. Take a look at the diagram. From our perspective on Earth, Jupiter and the Sun lie on opposite sides of our planet 180° apart. As the Sun sets Friday, Jupiter will rise in the east and remain visible all night until setting around sunrise exactly like a Full Moon.
So in a funny way, we have two Full Moons this week only one’s a planet.
Like me, a lot of you enjoy a good moonrise. That golden-orange globe, the crazy squished appearance at rising and the transition to the bright, white, beaming disk that throws enough light on a winter night to ski in the forest without a headlamp. All good reasons to be alive.
If Jupiter were moved to the Moon’s distance it would span about 20 degrees or 40 times the apparent diameter of the Full Moon. Credit: Roscosmos with additions by the author
To find when the moon rises for your town, click over to this moonrise calculator. As you step outside tonight to get your required Moon and Jupiter-shine, consider the scene if we took neighboring Jupiter and placed it at the same distance as the Moon. A recent series of such scenes was released by the Russian Federal Space Agency (Roscosmos). I included one here and added the Moon for you to compare. Is Jupiter enormous or what?
"The Harvest Moon", a circa 1833 oil painting by Samuel Palmer. Closely spaced moonrises meant extra light to bring in the crops in the days before electric lighting.
Tonight, September 8, the Harvest Moon rises the color of a fall leaf and spills its light across deserts, forests, oceans and cities. The next night it rises only a half hour later. And the next, too. The short gap of time between successive moonrises gave farmers in the days before electricity extra light to harvest their crops, hence the name.
The Harvest Moon is the full moon that falls closest to the autumnal equinox, the beginning of northern autumn. As the moon orbits the Earth, it moves eastward about one fist held at arm’s length each night and rises about 50 minutes later. You can see its orbital travels for yourself by comparing the moon’s nightly position to a bright star or constellation.
This full Moon is also a Proxigean or Perigee Full “Supermoon” (find out more about that here), which means the Moon is in a spot in its elliptical orbit where it is closer to Earth near the time it is full, making it look up to 15% larger than average full Moon.
Around the time of Harvest Moon, the full moon’s path is tilted at a shallow angle to the eastern horizon making with successive moonrises only about a half hour apart instead of the usual 50 minutes. Source: Stellarium
50 minutes is the usual gap between moonrises. But it can vary from 25 minutes to more than an hour depending upon the angle the moon’s path makes to the eastern horizon at rise time. In September that path runs above the horizon at a shallow angle. As the moon scoots eastward, it’s also moving northward this time of year.
This northward motion isn’t as obvious unless you watch the moon over the coming week. Then you’ll see it climb to the very top of its monthly path when it’s high overhead at dawn. The northward motion compensates for the eastward motion, keeping the September full moon’s path roughly parallel to the horizon with successive rise times only ~30 minutes apart.
The angle of the moon’s path to the horizon makes all the difference in moonrise times. At full phase in spring, the path tilts steeply southward, delaying successive moonrises by over an hour. In September, the moon’s path is nearly parallel to the horizon with successive moonrises just 30+ minutes apart. Times are shown for the Duluth, Minn. region. Illustration: Bob King
Exactly the opposite happened 6 months earlier this spring, when the moon’s path met the horizon at a steep angle. While it traveled the identical distance each night then as now, its tilted path dunked it much farther below the horizon night to night. The spring full moon moves east and south towards its lowest point in the sky. Seen from the northern hemisphere, that southward travel adds in extra time for the moon to reach the horizon and rise each successive night.
If all this is a bit mind-bending, don’t sweat it. Click HERE to find when the moon rises for your town and find a spot with a great view of the eastern horizon. You’ll notice the moon is orange or red at moonrise because the many miles of thicker atmosphere you look through when you gaze along the horizon scatters the shorter bluer colors from moonlight, tinting it red just as it does the sun.
A series of photos of the full moon setting over Earth’s limb taken by from space by NASA astronaut Don Pettit on April 16, 2003. Refraction causes a celestial object’s light to be bent upwards, so it appears higher than it actually is. The bottom half of the moon, closer to the horizon, is refracted strongest and “pushed” upward into the top half, making it look squished. Credit: NASA
The moon will also appear squished due to atmospheric refraction. Air is densest right at the horizon and refracts or bends light more strongly than the air immediately above it. Air “lifts” the bottom of the moon – which is closer to the horizon – more than the top, squishing the two halves together into an egg or oval shape.
How we perceive the moon’s size may have much to do with what’s around it. In this illustration, most of us seen the bottom moon as smaller, but they’re both exactly the same size. Crazy, isn’t it? Credit: NASA
You may also be entranced Monday night by the Moon Illusion, where the full moon appears unnaturally large when near the horizon compared to when viewed higher up. No one has come up with a complete explanation for this intriguing aspect of our perception, but the link above offers some interesting hypotheses.
Can you see craters with your naked eye? Yes! Try tonight through Wednesday night. Plato is the trickiest. Credit: Bob King
Finally, full moon is an ideal time to see several lunar craters with the naked eye. They’re not the biggest, but all, except Plato, are surrounded by bright rays of secondary impact craters that expand their size and provide good contrast against the darker lunar “seas”. Try with your eyes alone first, and if you have difficulty, use binoculars to get familiar with the landscape and then try again with your unaided eyes.
In contrast to the other craters, Plato is dark against a bright landscape. It’s a true challenge – I’ve tried for years but still haven’t convinced myself of seeing it. The others are easier than you’d think. Good luck and clear skies!
If you don’t have clear skies, Slooh will broadcast the “Super Harvest Moon” live from the Institute of Astrophysics of the Canary Islands, off the coast of Africa. Slooh’s live coverage will begin at 6:30 PM PDT / 9:30 PM EDT /01:30 UTC (8/9) – International times here. Slooh hosts are Geoff Fox and Slooh astronomer Bob Berman. Viewers can ask questions during the show by using hashtag #Sloohsupermoon. Watch below:
Last month's supermoon within 24 hours of perigee. Credit: Blobrana
Time to dust off those ‘what is a perigee Full Moon’ explainer posts… the supermoon once again cometh this weekend to a sky near you.
Yes. One. More. Time.
We’ve written many, many times — as have many astronomy writers — about the meme that just won’t die. The supermoon really brings ‘em out, just like werewolves of yore… some will groan, some will bemoan the use of a modernized term inserted into the common astronomical vernacular that was wrought by an astrologer, while others will exclaim that this will indeed be the largest Full Moon EVER…
But hey, it’s a great chance to explain the weird and wonderful motion of our nearest natural neighbor in space. Thanks to the Moon, those astronomers of yore had some great lessons in celestial mechanics 101. Without the Moon, it would’ve been much tougher to unravel the rules of gravity that we take for granted when we fling a probe spaceward.
The Moon reaches Full on Tuesday, September 9th at 1:38 Universal Time (UT), which is 9:38 PM EDT on the evening of the 8th. The Moon reaches perigee at less than 24 hours prior on September 8th at 3:30 UT — 22 hours and 8 minutes earlier, to be precise — at a distance 358,387 kilometres distant. This is less than 2,000 kilometres from the closest perigee than can occur, and 1,491 kilometres farther away than last month’s closest perigee of the year, which occurred 27 minutes prior to Full Moon.
A Proxigean or Perigee Full “Supermoon” as reckoned by our preferred handy definition of “a Full Moon occurring within 24 hours of perigee” generally occurs annually in a cycle of three over two lunar synodic periods, and moves slowly forward by just shy of a month through the Gregorian calendar per year. The next cycle of “supermoons” starts on August 30th, 2015, and you can see our entire list of cycles out through 2020 here.
What’s the upshot of all this? Well, aside from cluttering inboxes and social media with tales of the impending supermoon this weekend, the rising Moon will appear 33.5’ arc minutes in diameter as opposed to its usually quoted average of 30’ in size. And remember, that’s in apparent size as seen from our Earthly vantage point… can you spy a difference from one Full Moon to the next? Fun fact: the rising Moon is actually farther away from you to the tune of about one Earth radius than when it’s directly overhead at the zenith.
Fed up with supermoon-mania? The September Full Moon also has a more pedestrian name: The Harvest Moon. Actually, this is the Full Moon that falls nearest to the September Equinox, marking the start of the astronomical season of Fall in the northern hemisphere and Spring in the southern. In the current first half of the 21st century, the September Equinox falls on the 22nd or 23rd, meaning that the closest Full Moon (and thus the Harvest Moon) can sometimes fall in October, as last happened in 2009 and will occur again in 2017. In this instance, the September Full Moon would then be referred to as the Corn Moon as reckoned by the Algonquins, and is occasionally referred to as the Drying Grass Moon by Sioux tribes. In 2014, the Harvest Full Moon “misses” falling in October by about 32 hours!
The waning gibbous Moon of July 14th, 2014- shortly after the first supermoon of the year. Credit: Blobrana.
So, why is it known as the Harvest Moon? Well, in the age before artificial lighting (and artificial light pollution) the rising of the Full Moon as the Sun sets allowed for a few hours of extra illumination to bring in crops. In October, the same phenomenon gave hunters a few extra hours to track game by the light of the Full Hunters Moon, both essential survival activities before the onset of the long winter.
And that Full Harvest Moon seems to “stick around” on successive evenings. This is due to the relatively shallow angle of the evening ecliptic to the eastern horizon as seen from mid-northern latitudes in September.
The rising Full Moon on the evening of September 8th as seen from latitude 40 degrees north. Note the shallow angle of the ecliptic. Created using Stellarium.
Here’s a sample of rising times for the Moon this month as seen from Baltimore, Maryland at 39.3 degrees north latitude:
Saturday, September 6th: 5:43 PM EDT
Sunday, September 7th: 6:23 PM EDT
Monday, September 8th: 7:05 PM EDT
Tuesday, September 9th: 7:44 PM EDT
Wednesday, September 10th: 8:22 PM EDT
Note the Moon rises only ~40 minutes later on each successive evening.
The Full Harvest Moon of 2013 plus aircraft. Credit: Stephen Rahn.
We’re also headed towards a “shallow year” in 2015, as the Moon bottoms out relative to the ecliptic and only ventures 18 degrees 20’ north and south of the celestial equator at shallow minimum. This is due to what’s known as the Precession of the Line of Apsides as the gravitational pull of the Sun slowly drags the orbit of the Moon round the earth once every 8.85 years. The nodes where the ecliptic and path of the Moon meet — and solar and lunar eclipses occur — also move slowly in an opposite direction of the Moon’s motion, taking just over twice as long as the Precession of the Line of Apsides to complete one revolution around the ecliptic at 18.6 years. This is one of the more bizarre facts about the motion of the Moon: its orbital tilt of 5.1 degrees is actually fixed with respect to the ecliptic as traced out by the Earth’s orbit about the Sun, not our rotational axis. Native American and ancient Northern European knew of this, and the next “Long Night’s Moon” also called a “Lunar Standstill” when the Moon rides high in the northern hemisphere sky is due through 2024-2025.
The footprint of the September 11th occultation of Uranus. Credit: Occult 4.0.
And to top it off, the Moon occults Uranus just two days after Full on September 11th as seen from northeastern North America, Greenland, Iceland and northern Scandinavia. We’re in a cycle of occultations of Uranus by the Moon from late 2014 through 2015, and this will set the ice giant up for a spectacular close pass, and a rare occultation of the planet for a remote region in the Arctic during the October 8th total lunar eclipse…
The supermoon of August 10, 2014 rising behind Mt. Rundle and Banff, Alberta, Canada as shot from the Mt. Norquay viewpoint looking south over the valley. Credit and copyright: Alan Dyer.
Wow! The astrophotographers out there are getting artsy! Take a look at some of the most artistic images of the full Moon we’ve seen yet.
The August 10 full Moon was a so-called “super” Moon — and it was the “super-est” of a trio of full Moons being at perigee, or its closest approach to the Earth in its orbit. It was just 356,896 kilometers distant at 17:44 UTC, less than an hour from Full. You can see a comparison shot of the perigee and apogee Moons this year immediately below. Find all the technical details here, but enjoy a gallery of great images from around the world
A comparison the between two ‘extreme’ full Moons of 2014: the perigee Full Moon of August 10th, and the apogee full Moon of January 16. As seen from Central Italy. Credit and copyright: Giuseppe Petricca.
The August 10, 2014 ‘super’ Moon. Credit and copyright: Robbie Ambrose.
Supermoon timelapse composite on August 10 near the ship mast at Barnegat Light on Long Beach Island, New Jersey. Credit and copyright: FrankM301 on Flickr.
A cloudy look at the perigee Moon of August 10, 2014 along side the Desde el Obelisco, Malecón de Santo Domingo, Dominican Republic. Credit and copyright: Goku Abreu. ‘Super’ Moon, August 10, 2014, taken with Nikon D80 from Ottawa, Canada. Credit and copyright: Andrew Symes.
Super Moon (and a companion) rising over Brixton, South London. 10/08/2014. Credit and copyright: Owen Llewellyn.
Camaro and Full Moon – Aug 9, 2014.Taken from the Cairns Wharf in Australia at dusk using an iPhone 5. Three frames; two exposures each. Credit and copyright: Joseph Brimacombe.
It was prom night in Cairns… so the fancy cars were out. See Joseph’s other “prom supermoon” image here.
People watch the nearly ‘super’ Moon rise on August 9, 2014 near a lighthouse. Credit and copyright: Will Nourse.
Perigee Full Moon mosaic from August 10, 2014 (a first attempt at a mosaic!) Credit and copyright: Mary Spicer.
Perigee Moon rise over London on August 10, 2014. Credit and copyright: Sculptor Lil.
The perigee Moon from Toronto, Canada at 8:35 pm EDT. Credit and copyright: Rick Ellis.
A full Moon flyby, as seen from Paris, France. Credit and copyright: Sebastien Lebrigand.
Even NASA got into the “super Moon” astrophoto craze. NASA photographer Bill Ingalls took this beautiful image at The Peace Monument on the grounds of the United States Capitol, in Washington D.C. :
A perigree full moon or supermoon is seen over the The Peace Monument on the grounds of the United States Capitol, Sunday, August 10, 2014, in Washington. A supermoon occurs when the moon’s orbit is closest (perigee) to Earth at the same time it is full. Credit: (NASA/Bill Ingalls)
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