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.
The geometry that creates a total lunar eclipse. Credit: NASA
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.
Lunar Eclipse from New Jersey 12-21-2010. Credit: Robert Vanderbei
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.
The sky sparkles with the Moon (top, overexposed), Regulus, Venus, Mars, and Jupiter at dawn this morning October 7, 2015.
Tomorrow morning might be a good time to call for extra celestial traffic control. A slip of a crescent Moon will join a passel of planets in the dawn sky for the first of several exciting conjunctions over the next few days.
The scene facing east about 1 1/2 hours before sunrise Thursday morning Oct. 8. Let your eyes delight in the tumble of Moon and planets. Source: Stellarium
In the space of three mornings beginning tomorrow, four planets, the Moon and the star Regulus will participate in six separate conjunctions. Here’s how it’ll play out. Time are shown in UT / Greenwich Mean Time and Central Daylight and 1° equals two full moon diameters:
October 8: Venus 2.5° south of Regulus at 18 UT (1 p.m. CDT)
October 8: Regulus 3.1° north of the moon at 19 UT (2 p.m. CDT)
October 8: Venus 0.6° north of the moon at 20 UT (3 p.m. CDT)
October 9: Mars 3.2° north of the moon at 14 UT (9 a.m. CDT)
October 9: Jupiter 2.5° north of the moon at 21 UT (4 p.m.)
October 11: Mercury 0.8° north of the moon 11 UT (6 a.m. CDT)
The crescent Moon will be near Venus all day Thursday for the Americas until it sets in late afternoon. What a great opportunity to catch sight of the planet in the middle of the day. This binocular view depicts their arrangement around noon CDT Oct. 8, when the planet lies less than 2° from the Moon. Source:: Stellarium
Since several of the events occur in the middle of the afternoon for skywatchers in the Americas, here’s an expanded viewing guide:
* Thursday, October 8: Skywatchers will see Venus pass 2.5° south of Leo’s brightest star Regulus with a cool crescent moon a little more than 3° to the west of the brilliant planet. If you live in Japan and the Far East, you’ll see a splendidly close conjunction of the moon and Venus at dawn on October 9, when the pair will be separated by a hair more than one moon diameter (0.6°). At nearly the same time, the moon will be in conjunction with Regulus.
Observers in Australia and New Zealand will see the Moon occult Venus in a dark sky sky before dawn (or in daylight, depending on exact location) on the 9th. Click HERE for information, times and a map for the event.
Ready to set the alarm again? The following morning, October 9, the moon makes a neat triangle with Jupiter and Mars. Source: Stellarium
* Friday, October 9: An even thinner moon passes about 3° north of Mars in the Americas at dawn and approximately 4° from Jupiter. Watch for the three luminaries to sketch a nifty triangle in the eastern sky 90 minutes to an hour before sunrise. Venus will gaze down at the planetary conclave 10° further west.
There’s not much of the Moon left by Saturday morning the 11th. The knife-edge crescent will hang less than a degree below the planet Mercury 40 minutes before sunrise. Make sure you find a spot with a good eastern horizon. Source: Stellarium
* Sunday, October 11: Mercury, which has quietly taken up residence again in the dawn sky, hovers 0.8° above a hair-thin moon this morning at 6 a.m. CDT. Best views will be about 45 minutes before sunrise, when the pair rises high enough to clear distant trees. Bring binoculars to help you spot the planet.
After a short break, Mars and Jupiter will cozy up 0.4 degree apart just before the start of dawn on October 17 CDT. Venus won’t be far away. Source: Stellarium
You’re thinking, why does this all have to happen in the morning? Thankfully, sunrise occurs around 7 a.m. for many locations, so you can see all these cool happenings in twilight around 6 a.m. — not terribly unreasonable. And now that the The Martian has finally hit the movie theaters, what better time to see the planet in the flesh? By pure coincidence, the location of stranded astronaut Mark Watney in the fictional account — Acidalia Planitia (Mare Acidalium) — will be facing dawn risers across the Americas and Hawaii this week.
October wraps up with a tight trio of three planets before dawn. It will be the closest gathering of three planets since May 27, 2013. The next won’t happen till January 10, 2021. Source: Stellarium
Dare I say this string of continuous conjunctions is only a warm-up for more to come? Earth’s revolution around the Sun quickly brings Jupiter higher in the eastern sky, while Mars races eastward as if on a collision course. The following Saturday on October 17, the two will meet in conjunction less than 1/2 degree (one Full Moon width) apart. Very nice!
But it gets even better. On Tuesday morning, October 27, you’ll see all three planets huddle at dawn. One degree will separate Jupiter and Venus with Mars bringing up the rear several degrees further east. Feast on the view because there won’t be a more compact arrangement of three planets again until January 10, 2021.
The September 17, 2015 total lunar eclipse - the last of the recent tetrad of lunar eclipses over the past 17 months - was darker than expected. Several factors described below were in play. This photo was taken in Washington's Olympic National Park. Credit: Rick Klawitter
First off, a huge thank you to everyone who made and sent their Danjon scale estimate of the totally-eclipsed Moon’s brightness to Dr. Richard Keen, University of Colorado atmospheric scientist. Your data were crucial to his study of how aerosols in Earth’s atmosphere and other factors influence the Moon’s appearance.
Grateful for your help, Keen received a total of 28 observations from 7 different countries.
Graph created by Dr. Richard Keen plotting Danjon L values submitted by Universe Today readers and others that compare predicted values (top curve) with observed values. The Moon was about half as bright during totality as expected with L=1.9. Credit: Dr. Richard A. Keen
Using the Danjon information and estimates of the Moon’s brightness using the reverse binocular method, Keen crunched the data and concluded that the Moon was about 0.6 L (Danjon) units darker than expected and 0.4 magnitude dimmer, a brightness reduction of 33%. This agrees well with my own observation and possibly yours, too. No wonder so many stars sparkled near the Moon that night.
Lunar eclipse brightness is rated on the Danjon scale where “0” equals a dark gray totality and “4” a bright, coppery yellow. Credit: Bob King
I think it’s safe to say, most of us expected a normal or even bright totality. So why was it dark? Several factors were at play — one to do with the Moon’s location in Earth’s shadow, the other with a volcanic eruption and a third with long-term, manmade pollution.
During a perigean eclipse, the Moon passes more deeply into Earth’s shadow compared to one that happens near apogee, when the moon is most distant from Earth. Moon distances not to scale and for illustration only. Credit: Bob King
You’ll recall that the eclipse occurred during lunar perigee, when the Moon swings closest to Earth in its 27-day orbit. Being closer, it also tracked deeper into Earth’s umbra or inner shadow which narrows the farther back of the planet it goes. An apogean Moon (farthest from Earth) passes through a more tapered cone of darkness closer to the penumbra, where sunlight mixes with shadow. A Moon nearer Earth would find the umbral shadow roomier with the light-leaking penumbra further off in the distance.
On April 24, 2015, NASA’s Terra satellite acquired this photo of the ash and gas plume from Calbuco volcano in southern Chile. Credit: NASA
But there’s more. Working independently, Steve Albersof NOAA and Brazilian astronomer Helio Vital suggested another reason: aerosols in the atmosphere. “Earth’s stratosphere is no longer completely clean of volcanic ashes,” said Vital in an e-mail communication. “In fact, lingering aerosols (ash, dust, sulfuric acid droplets) from the explosion of Calbuco five months ago may be to blame for that excessive darkening.”
With the lunar horizon in the foreground, the Earth passes in front of the Sun on September 27, 2015 in this simulation, revealing the red ring of sunrises and sunsets along the limb of the planet responsible for illuminating the Moon during the eclipse. The clarity of the stratosphere at eclipse time can greatly affect lunar brightness during totality. The Earth and Sun are in Virgo for observers on the Moon with the bright star Beta Virginis at top. Click to see the video. Credit: NASA’s Scientific Visualization Studio
While much of the debris blasted into the stratosphere made for colorful sunsets in the southern hemisphere, some of that material has likely made its way to the northern hemisphere. Albers has noticed an increase in yellow and purple sunsets in his home town of Boulder in recent months, telltale signs of volcanic spew at play.
Forest fires that raged across the western states and Canadian provinces all spring and summer may also have contributed. Most of that smoke usually stays in the lower part of the atmosphere, but some may have found its way to the stratosphere, the very layer responsible for transmitting most of the sunlight that falls into Earth’s shadow and colors the moon.
Graph showing magnitude estimates of the Moon’s brightness during totality using the reverse binocular method. The predicted magnitude was -1.7 (a little brighter than Sirius) vs. the observed -1.3. Credit: Dr. Richard A. Keen
Sunlight has to pass through these light-absorbing minerals and chemicals on its way through the atmosphere and into Earth’s shadow. Less light means a darker moon during total eclipse. Coincidentally, much of the totally eclipsed Moon passed through the southern half of the umbra which “increased the effectiveness of the Calbuco aerosols (which are still more concentrated in the southern hemisphere than the northern) at dimming the light within the umbra,” writes Keen.
Oceanus Procellarum and Mare Imbrium are large, dark volcanic plains that contributed to the Moon’s faintness and dark-hued totality. Credit: Bob King
It also so happened that the darkest part of the moon coincided with two vast, dark volcanic plains called Oceanus Procellarum (Ocean of Storms) and Mare Imbrium, artificially enhancing the overall gloom over the northern half of the Moon.
U.S. satellite-derived map of PM2.5 (fine particulate matter which includes sulfates and soot) averaged over 2001-2006. Credit: Dalhousie University, Aaron van Donkelaar
Finally, the human hand may also have played a role in lunar color and brightness. The burning of coal and oil has caused a gradual increase in the amount of human-made sulfate aerosols in the atmosphere since the start of the industrial revolution. According to NASA, at current production levels, human-made sulfate aerosols are believed to outweigh the naturally produced sulfate aerosols. No surprise that the concentration of aerosols is highest in the northern hemisphere where most industrial activity is found.
Isn’t it fascinating that one blood-red Moon can tell us so much about the air we breathe? Thank you again for your participation!
A montage of images taken during the lunar eclipse on September 28, 2015, as see from Rambouillet, France. ISS transit duration (total): 1.7 seconds. This is the first time an ISS transit has been photographed during an eclipse. Credit and copyright: Thierry Legault.
To our knowledge, this is the first time anyone has ever photographed a transit of the International Space Station of the Moon DURING a lunar eclipse. And guess who did it?
Not surprisingly, it was the legendary astrophotographer Thierry Legault.
Usually, Thierry will travel up to thousands of miles to capture unique events like this, but this time, he only had to go 10 miles!
“Even if I caught a cold, I could not miss it,” Thierry told Universe Today in an email. “The Moon was very low on the horizon, only 16 degrees, so the seeing was not very good, but at least the sky was clear.”
Still, a stunning — and singularly unique — view of the “Super Blood Moon” eclipse!
See the video below:
It was a quick pass, with the ISS transit duration lasting a total of 1.7 seconds. Thierry uses CalSky to calculate where he needs to be to best capture an event like this, then studies maps, and has a radio synchronized watch to know very accurately when the transit event will happen.
In a previous article on Universe Today, Legault shared how he figures out the best places to travel to from his home near Paris to get the absolute best shots:
“For transits I have to calculate the place, and considering the width of the visibility path is usually between 5-10 kilometers, but I have to be close to the center of this path,” Legault explained, “because if I am at the edge, it is just like an eclipse where the transit is shorter and shorter. And the edge of visibility line of the transit lasts very short. So the precision of where I have to be is within one kilometer.”
Here’s the specs: ISS Speed: 25000 km/h (15500 mph). ISS Distance: 1100 km; Moon distance: 357,000 km (320x).
You can see other imagery from around the world of the lunar eclipse here, with images taken by Universe Today readers and staff.
Earlier this year, Thierry captured an ISS transit during the March 20, 2015 SOLAR eclipse, which you can see here.
Universe Today’s David Dickinson said he’s been trying to steer people towards trying to capture an ISS transit during a lunar eclipse for quite some time, and concurred that Thierry’s feat is a first. Dave made a video earlier this year to explain how people might photograph it during the April 2015 lunar eclipse, but unfortunately, no astrophotographers had any luck.
Thanks again to Thierry Legault for sharing his incredible work with Universe Today. Check out his website for additional imagery and information.
You can also see some of Legault’s beautiful and sometimes ground-breaking astrophotography here on Universe Today, such as images of the space shuttle or International Space Station crossing the Sun or Moon, or views of spy satellites in orbit.
If you want to try and master the art of astrophotography, you can learn from Legault by reading his book, “Astrophotography,” which is available on Amazon in a large format book or as a Kindle edition for those who might like to have a lit version while out in the field. It is also available at book retailers like Barnes and Noble and Shop Indie bookstores, or from the publisher, Rocky Nook, here.
"The red Moon did not disappoint tonight," writes Arnar Kristjansson. Credit: Arnar Kristjansson
Like some of you, I outran the clouds just in time to catch last night’s total lunar eclipse. What a beautiful event! Here are some gorgeous pictures from our readers and Universe Today staff — souvenirs if you will — of the last total lunar eclipse anywhere until January 31, 2018. The sky got so dark, and the Moon hung like a plum in Earth’s shadow for what seemed a very long time. Did you estimate the Moon’s brightness on the Danjon Scale? My brother and I both came up with L=2 from two widely-separated locations; William Wiethoff in Hayward, Wisconsin rated it L=1. All three estimates would indicate a relatively dark eclipse.
Nicely-done sequence of eclipse phases taken early September 28, 2015. Click to enlarge. Credit: Own Llewellyn
The darkness of the umbra was particularly noticeable in the west quarter of the Moon in the giant volcanic plain known as Oceanus Procellarum. This makes sense as that portion of the Moon was located closest to the center of the Earth’s dark, inner umbra. The plain is also dark compared to the brighter lunar highlights, which being more reflective, formed a sort of pale ring around the northern rim of the lunar disk.
Salute to the final eclipse of the current tetrad that began 17 months ago. Credit: Jason Major
The bottom or southern rim of the Moon, located farthest from the center of the umbra, appeared a lighter yellow-orange throughout totality.
Wide angle view of the Moon (lower left) during totality in a star-rich sky with the Aquila Milky Way visible at right. Credit: Bob King
This is just a small sampling of the excellent images arriving from our readers. More are flowing in on Universe Today’s Flickr site. Thank you everyone for your submissions!
A crowd gather to watch the Moon during partial eclipse prior to totality. Credit: Robert SparksA hint of the penumbra shows in this photo. Hint: look near left top. Credit: Roger HutchinsonA bloody Moon iindeed! Notice how dark Oceanus Procellarum (top) appears. Credit: Chris Lyons“Super Blood Moon”. Credit: Alok SinghalNice montage of images from eclipse start to finish. Credit: Mike GreenhamOne of the most awesome aspects of the eclipse was how many stars could be seen near the Moon. This picture was taken with a 100mm telesphoto lens. Credit: Bob KingRare shot of the totally eclipsed Moon and bright meteor. Credit: VegaStar Carpentier PhotographyA lucky break in the clouds made this photographer happy. Credit: Moe AliMary Spicer made exposures of the eclipsed Moon every 5 minutes. During totality, the Moon dropped behind a tree so she had to relocate the camera, hence the small gap in the sequence. 35 shots in total and stacked into one frame using StarStax. Credit: Mary SpicerThe Moon caught after totality between clouds through a small refracting telescope. Credit: Bob KingAnother fine montage displaying all the partial phase plus early, mid and late totality. Credit: Andre van der Hoeven
Weather looking a bit iffy tonight? Using the resources described below, you just might be able to escape the clouds. Credit: Bob King
We’ve arrived at eclipse day, so now the big question is, will it be clear? My favorite forecast for major astronomical events reads something like this: Fair skies tonight with light winds and lows in the middle 50s.While I hope that’s exactly what’s predicted for your town, in my corner of the world we’re expecting “increasing clouds with a chance for thunderstorms”.
That’s just not nice. Same by you? Here’s how to find that clear spot if you’re facing bad weather tonight.
One of my favorite cloud-checking sites is the GOES East view of the U.S., Canada and Central America taken from geostationary orbit. This map shows the scene at 10:45 a.m. CDT this morning. Credit: NASA
I usually check the GOES (Geostationary Operational Environmental Satellite) images that weather forecasters use to display and animate the movement of clouds and weather fronts during the nightly newscasts. Once I know the location and general drift of the clouds, I get in a car and drive to where it’s likely to either remain or become clear. Depending on the “magnitude” of the event I might drive 50 to 150 miles. If nothing else, doing astronomy guarantees many adventures.
GOES West view of the western U.S., Canada and Hawaii taken at 11 a.m. CDT. Credit: NASA
You’ll find these most helpful images at either the GOES East site, which features a photo of the entire mainland U.S., Central America and much of Canada, updated every 15 minutes. Since the satellite taking the photos is centered over the 75° west parallel of longitude, its focus is primarily the eastern two-thirds of the U.S. and Canada. For the western U.S., western Canada and Hawaii, head over to the GOES West site.
After you set the width and height to maximum values, you’ll get a picture like this, taken at 11 a.m. CDT. Credit: NASA
Once there, you’ll be presented with a big picture view of the U.S., etc., but you can click anywhere on the map for a zoomed-in look at a particular region. Before you do, set the “width” and “height” boxes to their maximum values of 1400 (width) and 1000 (height). That way you’ll get a full-screen, nifty, 1-kilometer image when you go in close. All images have a time stamp in the upper left corner given in Universal or Greenwich Mean Time (GMT). Subtract 4 hours to convert to Easter Daylight; 5 for CDT; 6 for MDT and 7 for PDT.
You can check back all day long for fresh photos and watch the march of the clouds over time. Or you can have the site assemble up to 30 of the most recent images into an animation loop and watch it as a movie. Combing current photos, the animation and your local forecast will inform your plans about whether to remain at home to watch the eclipse or get the heck out of town.
Infrared image of the east-central U.S. at 11 a.m. CDT today. Clouds can be seen and tracked at night using the infrared channel on the GOES East and West sites. Credit: NASA
When night arrives, you can still get a reasonably good idea of where the clouds are and aren’t by clicking on the infrared channel link at the top of the site. I also like to use the NCAR (National Center for Atmospheric Research Real-Time Weather Data) site. They offer a black and white infrared option that provides a clearer picture. At the site, select your “channel” then click on one of the regional acronyms on the interactive U.S. map.
So far, we’ve been talking about the weather in real time. When it comes to forecasts, one of the most useful tools of all and a true godsend to amateur astronomers is Attilla Danko’s ClearDarkSky site. Click on the Clear Sky Charts linkto access interactive charts for thousands of locations across the U.S., Canada and parts of Mexico. For example, if you click on Illinois, you’ll get a list of sky conditions for 105 locations throughout the state. The Chicagolink pops up six rows of data-packed squares with colors ranging from deep blue to white.
The cloud cover forecast for Chicago today Sept. 27 through early Tuesday Sept. 29 as depicted in Attilla Danko’s Clear Dark Sky site. The forecasts can be sponsored for a donation by various groups or individuals. This one is by the Chicago Astronomical Society. Copyright: Attilla Danko
The first row indicates cloud clover with varying shades of blue representing the percentage of clear sky. Medium blue means partly cloudy; white indicates 100% overcast. Additional data sets include sky transparency, seeing conditions, hours of darkness, wind, temperature and humidity. While no forecast is 100% accurate, the reliability of the models Danko uses makes Clear Sky Charts one of best tools available for skywatchers. Want a real treat? If you click on one of the squares in the Cloud Cover row, a large image showing cloud cover at the time will pop up. You’ll also find another, more general interactive cloud forecast graphic at WeatherForYou.com.
Thanks to a helpful reader suggestion, I recently learned of Clear Outside, a forecasting site similar to Clear Sky Charts but worldwide. Be sure to check it out. Satellite imagery like the U.S. GOES East and West is available for European and African observers at Sat24.
So what does the U.S. look like for weather tonight? Mostly clear skies are expected from New York State up through Maine, across the center of the country, the desert Southwest and the Northwest. Expect partly cloudy conditions (with some mostly cloudy spots) for the Upper and central Midwest, and mostly cloudy to overcast skies in the southern and southeastern seaboard states.
But who knows? By using these sites, you might just improve your chances of seeing what promises to be a spectacular lunar eclipse tonight. Some of you reading this undoubtedly have your own favorite weather hangouts. Please share them with us in the comments section. The more the merrier!
As always, if you’re completely shut out, here are a few sites where you can watch it live on the Web:
Depending on how clear the atmosphere is, the Moon's color can vary dramatically from one eclipse to another. The numbers, called the Danjon Scale, will help you estimate the color of Sunday night's eclipse. Credit: Bob King
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 Danjon Scale is used to estimate the color of the totally eclipsed moon. By making your own estimate, you can contribute to atmospheric and climate change science. Credit: Alexandre Amorim
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.
Graph showing the change in heating of the ground in fractions of degrees (vertical axis) as affected by volcanic eruptions and greenhouse warming since 1979. The blue shows volcanic cooling, the red shows greenhouse warming. Notice the rising trend in warming after 1996. Credit: Dr. Richard Keen
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 like Mt. Pinatubo, which erupted in June 1991 in the Philippines, inject tremendous quantities of ash and sulfur compounds high into the atmosphere, where they can temporarily block sunlight and cause a global drop in temperature. Credit: USGS
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”.
The moon was so dark during the December 1982 eclipse that Dr. Keen required a 3-minute-long exposure at ISO 160 to capture it. Credit: Richard Keen
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).
Lithograph from the German astronomy magazine Sirius compares the dark, featureless lunar disk during the 1884 eclipse a year after the eruption of Krakatoa (left) with a bright eclipse four years later, after the volcanic aerosols had settled out of the stratosphere (right).
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.
Two photos of Earth’s limb or horizon from orbit at sunset before and after the Mt. Pinatubo eruption. The top view shows a relatively clear atmosphere, taken August 30,1984. The bottom photo was taken August 8, 1991, less than two months after the eruption. Two dark layers of aerosols between 12 and 15 miles high make distinct boundaries in the atmosphere. Credit: NASA
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.
This map shows the Moon during mid-eclipse at 9:48 p.m. CDT. Selected stars are labeled with their magnitudes. Examine the Moon backwards through binoculars and find a star it most closely matches to determine its magnitude. If for instance, the Moon looks about halfway in brightness between Hamal and Deneb, then it’s magnitude 1.6. Click to enlarge. Source: Stellarium
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!
This time-lapse color panorama from China’s Chang’e-3 lander shows the Yutu rover at two different positions during its trek over the Moon’s surface at its landing site from Dec. 15-18, 2013. This view was taken from the 360-degree panorama. Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo. See our complete Yutu timelapse pano at NASA APOD Feb. 3, 2014: http://apod.nasa.gov/apod/ap140203.htm
China plans lunar far side landing with hardware similar to Chang’e-3 lander
This time-lapse color panorama from China’s Chang’e-3 lander shows the Yutu rover at two different positions during its trek over the Moon’s surface at its landing site from Dec. 15-18, 2013. This view was taken from the 360-degree panorama. Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo.
See our complete Yutu timelapse pano at NASA APOD Feb. 3, 2014: [/caption]
Chinese scientists plan to carry out the highly complex lunar landing mission using a near identical back up to the nations highly successful Chang’e-3 rover and lander – which touched down in December 2013.
If successful, China would become the first country to accomplish the history making task of a Lunar far side landing.
“The mission will be carried out by Chang’e-4, a backup probe for Chang’e-3, and is slated to be launched before 2020,” said Zou Yongliao from the moon exploration department under the Chinese Academy of Sciences, according to a recent report in China’s government owned Xinhua news agency.
Zou made the remarks at a deep-space exploration forum in China.
“China will be the first to complete the task if it is successful,” said Zou.
Chinese space scientists have been evaluating how best to utilize the Chang’e-4 hardware, built as a backup to Chang’e-3, ever since China’s successful inaugural soft landing on the Moon was accomplished by Chang’e-3 in December 2013 with the mothership lander and piggybacked Yutu lunar rover.
Chang’e-3/Yutu Timelapse Color Panorama This newly expanded timelapse composite view shows China’s Yutu moon rover at two positions passing by crater and heading south and away from the Chang’e-3 lunar landing site forever about a week after the Dec. 14, 2013 touchdown at Mare Imbrium. This cropped view was taken from the 360-degree timelapse panorama. See complete 360 degree landing site timelapse panorama herein and APOD Feb. 3, 2014. Chang’e-3 landers extreme ultraviolet (EUV) camera is at right, antenna at left. Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo – kenkremer.com. See our complete Yutu timelapse pano at NASA APOD Feb. 3, 2014: http://apod.nasa.gov/apod/ap140203.html
Plans to launch Chang’e-4 in 2016 were eventually abandoned in favor of further evaluation.
After completing an intense 12 month study ordered by China’s government, space officials confirmed that the lunar far side landing was the wisest use of the existing space hardware.
Chang’e-4 will be modified with a larger payload.
“Chang’e-4 is very similar to Chang’e-3 in structure but can handle more payload,” said Zou.
“It will be used to study the geological conditions of the dark side of the moon.”
The moon is tidally locked with the Earth so that only one side is ever visible. But that unique characteristic makes it highly attractive to scientists who have wanted to set up telescopes and other research experiments on the lunar far side for decades.
“The far side of the moon has a clean electromagnetic environment, which provides an ideal field for low frequency radio study. If we can can place a frequency spectrograph on the far side, we can fill a void,” Zou elaborated.
China will also have to launch another lunar orbiter in the next few years to enable the Chang’e-4 lander and rover to transmit signals and science data back to Chinese mission control on Earth.
In the meantime, China already announced its desire to forge ahead with an ambitious mission to return samples from the lunar surface later this decade.
The Chinese National Space Agency (CNSA) plans to launch the Chang’e-5 lunar sample return mission in 2017 as the third step in the nations far reaching lunar exploration program.
“Chang’e-5 will achieve several breakthroughs, including automatic sampling, ascending from the moon without a launch site and an unmanned docking 400,000 kilometers above the lunar surface,” said Li Chunlai, one of the main designers of the lunar probe ground application system, accoding to Xinhua.
The first step involved a pair of highly successful lunar orbiters named Chang’e-1 and Chang’e-2 which launched in 2007 and 2010.
The second step involved the hugely successful Chang’e-3 mothership lander and piggybacked Yutu moon rover which safely touched down on the Moon at Mare Imbrium (Sea of Rains) on Dec. 14, 2013 – marking China’s first successful spacecraft landing on an extraterrestrial body in history, and chronicled extensively in my reporting here at Universe Today.
360-degree time-lapse color panorama from China’s Chang’e-3 lander. This new 360-degree time-lapse color panorama from China’s Chang’e-3 lander shows the Yutu rover at five different positions, including passing by crater and heading south and away from the Chang’e-3 lunar landing site forever during its trek over the Moon’s surface at its landing site from Dec. 15-22, 2013 during the 1st Lunar Day. Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo – kenkremer.com. See our Yutu timelapse pano at NASA APOD Feb. 3, 2014: http://apod.nasa.gov/apod/ap140203.html
See above and herein our time-lapse photo mosaics showing China’s Yutu rover dramatically trundling across the Moon’s stark gray terrain in the first weeks after she rolled all six wheels onto the desolate lunar plains.
The complete time-lapse mosaic shows Yutu at three different positions trekking around the landing site, and gives a real sense of how it maneuvered around on its 1st Lunar Day.
The 360 degree panoramic mosaic was created by the imaging team of scientists Ken Kremer and Marco Di Lorenzo from images captured by the color camera aboard the Chang’e-3 lander and was featured at Astronomy Picture of the Day (APOD) on Feb. 3, 2014.
Chang’e-3 and Yutu landed on a thick deposit of volcanic material.
Mosaic of the Chang’e-3 moon lander and the lunar surface taken by the camera on China’s Yutu moon rover from a position south of the lander during Lunar Day 3. Note the landing ramp and rover tracks at left. Credit: CNSA/SASTIND/Xinhua/Marco Di Lorenzo/Ken Kremer
China is only the 3rd country in the world to successfully soft land a spacecraft on Earth’s nearest neighbor after the United States and the Soviet Union.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
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