It’s that wonderful time of year again when the Harvest Moon teeters on the horizon at sunset. You can watch the big orange globe rise on Friday (Sept. 16) from your home or favorite open vista just as soon as the Sun goes down. Despite being one of the most common sky events, a Full Moon rise still touches our hearts and minds every time. No matter how long I live, there will never be enough of them.
To see a moonrise, the most important information you need is the time the moon pops up for your city, which you’ll find by using this Moonrise and Moonset calculator. Once you know when our neighborly night light rises, pre-arrange a spot you can walk or drive to 10-15 minutes beforehand. The waiting is fun. Who will see it first? I’ll often expect to see the Moon at a certain point along the horizon then be surprised it’s over there.
Depending on how low to the horizon you can see, it’s possible, especially over water, to catch the first glimpse of lunar limb breaching the horizon. This still can be a tricky feat because the Moon is pale, and when it rises, shows little contrast against the still-bright sky. Since the Moon moves about one outstretched fist to the east (left in the northern hemisphere) each night, if you wait until one night after full phase, the Moon will rise in a much darker sky and appear in more dramatic contrast against the sky background.
Look closely at the rising Moon with both naked eye and binoculars and you might just see a bit of atmospheric sorcery at work. Refraction, illustrated the icy moonrise image above, is the big one. It creates the squashed Moon shape. But more subtle things are happening that depend on how turbulent or calm the air is along your line of sight to our satellite.
Rippling waves “sizzling” around the lunar circumference can be striking in binoculars though the effect is quite subtle with the naked eye. Much easier to see without any optical aid are the weird shapes the Moon can assume depending upon the state of the atmosphere. It can looked stretched out like a hot air balloon, choppy with a step-like outline around its bottom or top, square, split into two moons or even resemble a “mushroom cloud”.
If you make a point to watch moonrises regularly, you’ll become acquainted as much with Earth’s atmosphere as with the alien beauty of our sole satellite.
This Full Moon is special in at least two ways. First, it will undergo a penumbral eclipse for skywatchers across eastern Europe, Africa, Asia and Australia. Observers there should watch a dusky gray shading over the upper or northern half of the Moon around the time of maximum eclipse. The link will take you to Dave Dickinson’s excellent article that appeared earlier here at Universe Today.
In the northern hemisphere, September’s Full Moon is named the Harvest Moon, defined as the Full Moon closest to the autumnal equinox, which occurs at 9:21 a.m. CDT (14:21 UT) on the 22nd. Normally, the Moon rises on average about 50 minutes later each night as it moves eastward along its orbit. But at Harvest Moon, successive moonrises are separated by a half-hour or less as viewed from mid-northern latitudes. The short gap of time between between bright risings gave farmers in the days before electricity extra light to harvest their crops, hence the name.
Why the faster-than-usual moonrises? Every September, the Full Moon’s nightly travels occur at a shallow angle to the horizon; as the moon scoots eastward, it’s also moving northward this time of year as shown in the illustration above. The northern and eastward motions combine to make the Moon’s path nearly level to the horizon. For several nights in a row, it only takes a half-hour for the Earth’s rotation to carry the Moon up from below the horizon. In spring, the angle is steep because the Moon is then moving quickly southward along or near the ecliptic, the path it takes around the sky. Rising times can exceed an hour.
As you gaze at the Moon over the next several nights, take in the contrast between its ancient crust, called the lunar highlands, and the darker seas (also known as maria, pronounced MAH-ree-uh). The crust appears white because it’s rich in calcium and aluminum, while the maria are slightly more recent basaltic lava flows rich in iron, which lends them a darker tone. Thanks to these two different types of terrain it’s easy to picture a male or female face or rabbit or anything your imagination desires.
On March 8, 2016 (March 9 local time) the Moon briefly blocked the light from the Sun in what was the only total solar eclipse of the year. The event was visible across portions of southeast Asia, Indonesia, and Micronesia, and was observed by both skywatchers on the ground in person and those watching live online around the world. While to most the view was of a silhouetted Moon slowly carving away the disk of the Sun before totality revealed a shimmering corona, the view from space looking back at Earth showed the Moon’s dark shadow passing over islands, clouds, and sea.
If the Sun, Earth and Moon are lined up, shouldn’t we get a lunar and solar eclipse every month? Clearly, we don’t, but why not?
Coincidences happen all the time. Right, Universe? One of the most amazing is that Moon and the Sun appear to be almost exactly the same size in the sky and they’re both the size of your pinky fingernail held at arm’s length. These coincidences just keep piling up. Thanks Universe?
There are two kinds of eclipses: solar and lunar. Well, there’s a third kind, but we’d best not think about that.
A solar eclipse occurs when the Moon passes in between the Earth and Sun, casting a shadow down on the surface of our planet. If you’re in the path of the shadow, the Moon destroys the Sun. No, wait, I mean the Moon blocks the Sun briefly.
A lunar eclipse happens when the Moon passes through the Earth’s shadow. We see one limb of the Moon darken until the entire thing is in shadow.
You’ve got the Sun, Earth and Moon all in a line. Where they’re like this, it’s a solar eclipse, and when they’re like this, it’s a lunar eclipse.
If the Moon takes about a month to orbit the Earth, shouldn’t we get an eclipse every two weeks? First a solar eclipse, and then two weeks later, lunar eclipse, back and forth? And occasionally a total one of the heart? But we don’t get them every month, in fact, it can take months and months between eclipses of any kind.
If the Sun, Earth and Moon were truly lined up perfect, this would be the case. But the reality is that they’re not lined up. The Moon is actually on an inclined plane to the Earth.
Imagine the Solar System is a flat disk, like a DVD. You kids still know what those are, right? This is the plane of the ecliptic, and all of the planets are arranged in that disk.
But the Moon is on another disk, which is inclined at an angle of 5.14 degrees. So, if you follow the orbit of the Moon as it goes around the Earth, sometimes it’s above the plane of the ecliptic and sometimes it’s below. So the shadow cast by the Moon misses the Earth, or the shadow cast by the Earth misses the Moon.
But other times, the Sun, Moon and Earth are aligned, and we get eclipses. In fact, eclipses tend to come in pairs, with a solar eclipse followed by a lunar eclipse, because everything is nicely aligned.
Wondering why the Moon turns red during a lunar eclipse? It’s the same reason we see red sunsets here on Earth – the atmosphere filters out the green to violet range of the spectrum, letting the red light pass through.
The Earth’s atmosphere refracts the sunlight so that it’s bent slightly, and can illuminate the Moon during the greatest eclipse. It’s an eerie sight, and well worth hanging around outside to watch it happen. We just had recently had a total lunar eclipse, did you get a chance to see it? Wasn’t it awesome?
Don’t forget about the total solar eclipse that’s going to be happening in August, 2017. It’s going to cross the United States from Oregon to Tennessee and should be perfect viewing for millions of people in North America. We’ve already got our road trip planned out.
Are you planning to see the 2017 eclipse? Tell us your plans in the comments below.
There are many ways to enjoy tomorrow night’s total lunar eclipse. First and foremost is to sit back and take in the slow splendor of the Moon entering and exiting Earth’s colorful shadow. You can also make pictures, observe it in a telescope or participate in a fun science project by eyeballing the Moon’s brightness and color. French astronomer Andre Danjon came up with a five-point scale back in the 1920s to characterize the appearance of the Moon during totality. The Danjon Scale couldn’t be simpler with just five “L values” from 0 to 4:
L=0: Very dark eclipse. Moon almost invisible, especially at mid-totality.
L=1: Dark Eclipse, gray or brownish in coloration. Details distinguishable only with difficulty.
L=2: Deep red or rust-colored eclipse. Very dark central shadow, while outer edge of umbra is relatively bright.
L=3: Brick-red eclipse. Umbral shadow usually has a bright or yellow rim.
L=4: Very bright copper-red or orange eclipse. Umbral shadow has a bluish, very bright rim.
The last few lunar eclipses have been bright with L values of 2 and 3. We won’t know how bright totality will be during the September 27-28 eclipse until we get there, but chances are it will be on the bright side. That’s where you come in. Brazilian amateur astronomers Alexandre Amorim and Helio Carvalho have worked together to create a downloadable Danjonmeterto make your own estimate. Just click the link with your cellphone or other device and it will instantly pop up on your screen.
On the night of the eclipse, hold the phone right up next to the moon during mid-eclipse and estimate its “L” value with your naked eye. Send that number and time of observation to Dr. Richard Keen at [email protected] For the sake of consistency with Danjon estimates made before mobile phones took over the planet, also compare the moon’s color with the written descriptions above before sending your final estimate.
Keen, an emeritus professor at the University of Colorado-Boulder Department of Atmospheric and Oceanic Sciences, has long studied how volcanic eruptions affect both the color of the eclipsed moon and the rate of global warming. Every eclipse presents another opportunity to gauge the current state of the atmosphere and in particular the dustiness of the stratosphere, the layer of air immediately above the ground-hugging troposphere. Much of the sunlight bent into Earth’s shadow cone (umbra) gets filtered through the stratosphere.
Volcanoes pump sulfur compounds and ash high into the atmosphere and sully the otherwise clean stratosphere with volcanic aerosols. These absorb both light and solar energy, a major reason why eclipses occurring after a major volcanic eruption can be exceptionally dark with L values of “0” and “1”.
One of the darkest in recent times occurred on December 30, 1982 after the spectacular spring eruption of Mexico’s El Chichon that hurled some 7 to 10 million tons of ash into the atmosphere. Sulfurous soot circulated the globe for weeks, absorbing sunlight and warming the stratosphere by 7°F (4°C).
Meanwhile, less sunlight reaching the Earth’s surface caused the northern hemisphere to cool by 0.4-0.6°C. The moon grew so ashen-black during totality that if you didn’t know where to look, you’d miss it.
Keen’s research focuses on how the clean, relatively dust-free stratosphere of recent years may be related to a rise in the rate of global warming compared to volcano-induced declines prior to 1996. Your simple observation will provide one more data point toward a better understanding of atmospheric processes and how they relate to climate change.
If you’d like to do a little more science during the eclipse, Keen suggests examining the moon’s color just after the beginning and before the end of totality to determine an ‘L’ value for the outer umbra. You can also determine the moon’s overall brightness or magnitude at mid-eclipse by comparing it to stars of known magnitude. The best way to do that is to reduce the moon down to approximately star-size by looking at it through the wrong end of a pair of 7-10x binoculars and compare it to the unreduced naked eye stars. Use this link for details on how it’s done along with the map I’ve created that has key stars and their magnitudes.
The table below includes eclipse events for four different time zones with emphasis on mid-eclipse, the time to make your observation. Good luck on Sunday’s science project and thanks for your participation!
Dr. Sara Seager, whose research focuses on computer models of exoplanet atmospheres, interiors, and biosignatures. Her favorite projects involve the search for planets like Earth with signs of life
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.
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.
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.
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.
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.
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.
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.
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.
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?
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.
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.
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.
Get ready for one awesome total lunar eclipse early Saturday morning April 4th. For the third time in less than a year, the Moon dips into Earth’s shadow, its dazzling white globe turning sunset red right before your eyes. All eclipses are not-to-miss events, but Saturday’s totality will be the shortest in a century. Brief but beautiful – just like life. Read on to find out how to make the most of it.
Lunar eclipses don’t usually happen in any particular order. A partial eclipse is followed by a total is followed by a penumbral and so on. Instead, we’re in the middle of a tetrad, four total eclipses in a row with no partials in between. The final one happens on September 28. Even more remarkable, part or all of them are visible from the U.S. Tetrads will be fairly common in the 21st century with eight in all. We’re lucky — between 1600 and 1900 there were none! For an excellent primer on the topic check out fellow Universe Today writer David Dickinson’s “The Science Behind the Blood Moon Tetrad“.
Lots of people have taken to calling the tetrad eclipses Blood Moons, referring to the coppery color of lunar disk when steeped in Earth’s shadow and the timing of both April events on the Jewish Passover. Me? I prefer Bacon-and-Eggs Moon. For many of us, the eclipse runs right up till sunrise with the Moon setting in bright twilight around 6:30 a.m. What better time to enjoy a celebratory breakfast with friends after packing away your gear?
But seriously, Saturday morning’s eclipse will prove challenging for some. While observers in far western North America, Hawaii, Japan, New Zealand and Australia will witness the entire event, those in the mountain states will see the Moon set while still in totality. Meanwhile, skywatchers in the Midwest and points East will see only the partial phases in a brightening dawn sky. Here are the key times of eclipse events by time zone:
Eclipse Events EDT CDT MDT PDT
Penumbra eclipse begins
Partial eclipse begins
Total eclipse begins
Total eclipse ends
Partial eclipse ends
Penumbra eclipse ends
* During the penumbral phase, shading won’t be obvious until ~30 minutes before partial eclipse.
This eclipse will also be the shortest total eclipse of the 21st century; our satellite spends just 4 minutes and 43 seconds inside Earth’s umbra or shadow core. That’s only as long as a typical solar eclipse totality. Ah, the irony.
Better have your camera ready or you’ll miss it. The maps below show the maximum amount of the Moon visible shortly before setting from two eastern U.S. cities and the height of the totally eclipsed Moon from two western locations. Click each panel for more details about local circumstances.
Now that you know times and shadow coverage, let’s talk about the fun part — what to look for as the event unfolds. You’ll need to find a location in advance with a good view to the southwest as most of the action happens in that direction. Once that detail’s taken care of and assuming clear weather, you can kick back in a folding chair or with your back propped against a hillside and enjoy.
The entire eclipse can be enjoyed without any optical aid, though I recommend a look through binoculars now and then. The eclipsed Moon appears distinctly three-dimensional with only the slightest magnification, hanging there like an ornament among the stars. The Earth’s shadow appears to advance over the Moon, but the opposite is true; the Moon’s eastward orbital motion carries it deeper and deeper into the umbra.
Nibble by nibble the sunlit Moon falls into shadow. By the time it’s been reduced to half, the shaded portion looks distinctly red even to the naked eye. Notice that the shadow is curved. We live on a spherical planet and spheres cast circular shadows. Seeing the globe of Earth projected against the Moon makes the roundness of our home planet palpable.
When totality arrives, the entire lunar globe throbs with orange, copper or rusty red. These sumptuous hues originate from sunlight filtered and bent by Earth’s atmosphere into the umbral shadow. Atmospheric particles have removed all the cooler colors, leaving the reds and oranges from a billion sunrises and sunsets occurring around the planet’s circumference. Imagine for a moment standing on the Moon looking back. Above your head would hang the black disk of Earth, nearly four times the size of the Moon in our sky, ringed by a narrow corona of fiery light.
Color varies from one eclipse to the next depending on the amount of water, dust and volcanic ash suspended in Earth’s atmosphere. The December 30, 1982 eclipse was one of the darkest in decades due to a tremendous amount of volcanic dust from the eruption of the Mexican volcano El Chichon earlier that year.
The more particles and haze, the greater the light absorption and darker the Moon. That said, this eclipse should be fairly bright because the Moon does not tread deeply into Earth’s shadow. It’s in for a quick dip of totality and then resumes partial phases.
It’s northern edge, located close to the outer fringe of Earth’s umbra, should appear considerably brighter than the southern, which is closer to the center or darkest part of the umbra.
Besides the pleasure of seeing the Moon change color, watch for the sky to darken as totality approaches. Eclipses begin with overwhelming moonlight and washed out, star-poor skies. As the Moon goes into hiding, stars return in a breathtaking way over a strangely eerie landscape. Don’t forget to turn around and admire the glorious summer Milky Way rising in the eastern sky.
Lunar eclipses remind us we live in a Solar System made of these beautiful, moving parts that never fail to inspire awe when we look up to notice.
In case you can’t watch the eclipse from your home due to weather or circumstance, our friends at the Virtual Telescope Project and SLOOHwill stream it online.