Io casts a crisp circular shadow on the the cloud tops in Jupiter's atmosphere in this JunoCam image processed by Kevin Gill. Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill https://creativecommons.org/licenses/by/2.0/
The JunoCam onboard NASA’s Juno spacecraft continues to provide we Earthbound humans with a steady stream of stunning images of Jupiter. We can’t get enough of the gas giant’s hypnotic, other-worldly beauty. This image of Io passing over Jupiter is the latest one to awaken our sense of wonder.
This image was processed by Kevin Gill, a NASA software engineer who has produced other stunning images of Jupiter.
This sequence of photos taken on October 18, 2013 nicely show the different phases of a penumbral lunar eclipse. The coming penumbral eclipse will likely appear even darker because Earth’s shadow will shade to the top (northern) half of the Moon rich in dark lunar “seas” at maximum. Credit: AstroTripper 2000
Not many people get excited about a penumbral eclipse, but when it’s a deep one and the only lunar eclipse visible in North America this year, it’s worth a closer look. What’s more, this Friday’s eclipse happens during convenient, early-evening viewing hours. No getting up in the raw hours before dawn.
Lunar eclipses — penumbral, partial and total — always occur at Full Moon, when the Moon, Earth and Sun line up squarely in a row in that order. Only then does the Moon pass through the shadow cast by our planet. Credit: Starry Night with additions by the author
During a partial or total lunar eclipse, the full moon passes first through the Earth’s outer shadow, called the penumbra, before entering the dark, interior shadow or umbra. The penumbra is nowhere near as dark as the inner shadow because varying amounts of direct sunlight filter into it, diluting its duskiness.
To better understand this, picture yourself watching the eclipse from the center of the Moon’s disk (latitude 0°, longitude 0°). As you look past the Earth toward the Sun, you would see the Sun gradually covered or eclipsed by the Earth. Less sunlight would be available to illuminate the Moon, so your friends back on Earth would notice a gradual dimming of the Moon, very subtle at first but becoming more noticeable as the eclipse progressed.
This diagram shows an approximation of the Sun’s position and size as viewed by an observer at the center of the lunar disk during Friday’s penumbral eclipse. More sunlight shines across the Moon early in the eclipse, making the penumbral shadow very pale, but by maximum (right), half the sun is covered and the Moon appears darker and duskier as seen from Earth. During a total lunar eclipse, the sun is hidden completely. Credit: Bob King with Earth image by NASA
As the Moon’s leading edge approached the penumbra-umbra border, the Sun would narrow to a glaring sliver along Earth’s limb for our lucky lunar observer. Back on Earth, we’d notice that the part of the Moon closest to the umbra looked strangely gray and dusky, but the entire lunar disk would still be plainly visible. That’s what we’ll see during Friday’s eclipse. The Moon will slide right up to the umbra and then roll by, never dipping its toes in its dark waters.
During a partial eclipse, the Moon keeps going into the umbra, where the Sun is completely blocked from view save for dash of red light refracted by the Earth’s atmosphere into what would otherwise be an inky black shadow. This eclipse, the Moon only flirts with the umbra.
The moon’s orbit is tilted 5.1 degrees in relation to Earth’s orbit, so most Full Moons, it passes above or below the shadow and no eclipse occurs. Credit: Bob King
Because the moon’s orbit is tilted about 5° from the plane of Earth’s orbit, it rarely lines up for a perfect bullseye total eclipse: Sun – Earth – Moon in a straight line in that order. Instead, the moon typically passes a little above or below (north or south) of the small, circle-shaped shadow cast by our planet, and no eclipse occurs. Or it clips the outer edge of the shadow and we see — you guessed it — a penumbral eclipse.
Earth’s shadow varies in size depending where you are in it. Standing on the ground during twilight, it can grow to cover the entire sky, but at the moon’s distance of 239,000 miles, the combined penumbra and umbra span just 2.5° of sky or about the width of your thumb held at arm’s length.
The moon passes through Earth’s outer shadow, the penumbra, on Feb. 10-11. In the umbra, the sun is blocked from view, but the outer shadow isn’t as dark because varying amounts of sunlight filter in to dilute the darkness. Times are Central Standard. Credit: F. Espenak, NASA’s GFSC with additions by the author
Because the Moon travels right up to the umbra during Friday’s eclipse, it will be well worth watching.The lower left or eastern half of the moon will appear obviously gray and blunted especially around maximum eclipse as it rises in the eastern sky that Friday evening over North and South America. I should mention here that the event is also visible from Europe, Africa, S. America and much of Asia.
This map shows where the eclipse will be visible. Most of the U.S. will see at least part of the event. Credit: F. Espenak, NASA’s GFSC
For the U.S., the eastern half of the country gets the best views. Here are CSTand UTtimes for the different stages. To convert from CST, add an hour for Eastern, subtract one hour for Mountain and two hours for Pacific times. UT stands for Universal Time, which is essentially the same as Greenwich or “London” Time except when Daylight Saving Time is in effect:
This is a simulated view of the Full Snow Moon at maximum eclipse Friday evening low in the eastern sky alongside the familiar asterism known as the Sickle of Leo. Created with Stellarium
Eclipse begins: 4:34 p.m. (22:34 p.m. UT) Maximum eclipse (moon deepest in shadow): 6:44 p.m. (00:43 UT Feb. 11) Eclipse ends: 8:53 p.m. (2:53 UT Feb. 11)
You can see that the eclipse plays out over more than 4 hours, though I don’t expect most of us will either be able or would want to devote that much time. Instead, give it an hour or so when the Moon is maximally in shadow from 6 to 7:30 p.m. CST; 7-8:30 EST; 5-6:30 p.m. MST and around moonrise Pacific time.
This should be a fine and obvious eclipse because around the time of maximum, the darkest part of the penumbra shades the dark, mare-rich northern hemisphere of the Moon. Dark plus dark equals extra dark! Good luck and clear skies!
The Moon's shadow is cast across Indonesia in this view from the DSCOVR spacecraft, March 9, 2016. (Courtesy of the DSCOVR EPIC team.)
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.
"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 Sparks
A hint of the penumbra shows in this photo. Hint: look near left top. Credit: Roger Hutchinson
A bloody Moon iindeed! Notice how dark Oceanus Procellarum (top) appears. Credit: Chris Lyons
“Super Blood Moon”. Credit: Alok Singhal
Nice montage of images from eclipse start to finish. Credit: Mike Greenham
One 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 King
Rare shot of the totally eclipsed Moon and bright meteor. Credit: VegaStar Carpentier Photography
A lucky break in the clouds made this photographer happy. Credit: Moe Ali
Mary 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 Spicer
The Moon caught after totality between clouds through a small refracting telescope. Credit: Bob King
Another fine montage displaying all the partial phase plus early, mid and late totality. Credit: Andre van der Hoeven
On Wednesday morning October 8, Earth's shadow will nibble away at the moon for this year's second total lunar eclipse. Credit: Bob King
Ready for Wednesday’s morning lunar eclipse? Some people – and I envy them at times – treat an eclipse more casually. They enjoy the show with no desire to set up a telescope or take a photo. For those of us can’t part with our cameras, here’s a little guide to help you get better pictures.
From Philadelphia and other eastern U.S. cities the partial phases of the eclipse will take place with the moon well up in the western sky. By the start of totality, the moon will have dropped to within about 6º of the horizon as shown here. Source: Stellarium
If you’re also into photography and would like to grab a few shots, here are a few tips on what equipment you’ll need and camera settings. This eclipse offers unique opportunities especially for the eastern half of the country because the eclipsed moon will be low in the western sky near the start of and during morning twilight.
In the Midwest at the start of the hour-long totality, the red moon will be about 20º (two fists) above the western horizon. From the East Coast the moon slips into total eclipse only a half hour before sunrise 6-7º high. So if you live in the eastern half of the country, find a site with a good view to the west.
Seen from Denver, total eclipse begins with the moon 30º high (three fists). All of totality and all partial phases of the eclipse will be visible from western Midwest west to Hawaii and Alaska. Source: Stellarium
A low moon means easier framing with a pleasing foreground like a grove of fall trees, a church or distant line of mountain peaks. And the lower it drops, the longer the telephoto lens you can use to enlarge the moon relative to the foreground. When the moon is high in the sky it’s more difficult to find a suitable foreground.
Sometimes it’s nice to have a foreground object to add character to your eclipse photos. Last April’s totally eclipsed moon joins the old Central High School clock tower in downtown Duluth, Minn. Mars at upper right. Details: 80mm lens, f/5, 1.6-second exposure at ISO 400 on a tripod. Credit: Bob King
As the scene brightens during twilight, balancing the light of the dim moon, your photos will get even more interesting. Textures and details in foreground objects will stand out instead of appearing as silhouettes.
Use the table below to plan when to watch depending on your time zone. The blanks mean the moon will have set by the time of the event.
Eclipse Events EDT CDT MDT PDT
Penumbra first visible
4:45 a.m.
3:45 a.m.
2:45 a.m.
1:45 a.m.
Partial eclipse begins
5:15 a.m.
4:15 a.m.
3:15 a.m.
2:15 a.m.
Total eclipse begins
6:25 a.m.
5:25 a.m.
4:25 a.m.
3:25 a.m.
Mid-eclipse
6:55 a.m.
5:55 a.m.
4:55 a.m.
3:55 a.m.
Total eclipse ends
7:24 a.m.
6:24 a.m.
5:24 a.m.
4:24 a.m.
Partial eclipse ends
———
7:34 a.m.
6:34 a.m.
5:34 a.m.
Penumbra last visible
———
———
7:05 a.m.
6:05 a.m.
Exposures and lens settings
Partial phase during the April 14-15 eclipse this year. Details: Telescope (=1300mm telephoto lens) at f/11, 1/250 second at ISO 400. Credit: Bob King
The full moon and even the partially eclipsed moon (up to about half) are so bright you can shoot a handheld photo without resorting to a tripod. Exposures at ISO 400 are in the neighborhood of f/8 at 1/250-1/500 second. Only thing is, all you’ll get is the moon surrounded by blackness. These exposures are so brief almost nothing will show in your foreground except for possibly moonlit clouds. That’s usually fine for the early partial phases.
Once the moon is more than half smothered by shadow, open up your lens to a wider setting – f/2.8 to f/4 – or increase the exposure. Let the back of the camera be your guide. If the images look too bright, dial back. If too dim, increase exposure or open the lens to a wider aperture.
To capture the encroaching shadow during partial phases you’ll need to overexpose the sunlit part of the moon. Details: f/11, 2-second exposure at ISO 400. Credit: Bob King
While you can continue to shoot the partially eclipsed moon at f/8 from 1/30-1/125 second, you’ll miss the best part – the portion filling up with Earth’s red shadow. To capture that, break out the tripod, open the lens all the way up – f/2.8-f/4 – and expose at ISO 400 between 1/4 and 1 second.
You can also shoot at ISO 800 and cut those times in half, important if you’re using a longish telephoto lens. Remember, Earth’s rotation means the moon’s on the move and will show trailing if you expose longer than a few seconds. On the other hand, this won’t be a problem if you’re shooting with a wide angle lens though they have their limits, too.
The moon completely immersed in Earth’s umbra during totality. Details: f/11, 6-second exposure, ISO 400. To prevent trailing I used a motorized mount to track the moon. Credit : Bob King
During totality, expose anywhere from 1/2 to 5 seconds at f/2.8-4.5 at ISO 400. Let’s say you want to include both scenic foreground and stars in the picture using a wide angle or standard lens. Dial up the ISO to 800, open your lens wide and expose between 6-10 seconds. On the 6-second end you’ll catch only the brightest stars, but the moon won’t show trailing; on the longer end you’ll get lots more stars with some overexposure of the eclipsed moon.
Of course, you can go to even higher ISOs and shorten exposure times considerably. But in all but the newest, high-end cameras that comes at the price of increased graininess and less color saturation.
Wide scene from April’s total eclipse with Spica below the moon and Mars to the right. Details: 24mm lens at f/2.8, 8-second exposure at ISO 800. The moon was deliberately overexposed to show it in a field of stars. You can vary the exposure to your taste but the shorter it is, the fewer stars. Longer exposures will show trailing. Credit: Bob King
Where parts of the eclipse happen in twilight, even mobile phones may suffice. There should be enough light to capture a pretty scene with the moon just emerging from total eclipse and during the ensuing partial phases.
The partial lunar eclipse of June 4, 2012, pre-dawn at moonset, from home in southern Alberta. This is a single exposure with the Canon 60Da and 18-200mm Sigma lens at 115mm and at f/5.6 for 0.4 sec at ISO 160. Copyright: Alan Dyer
If you’re clouded out or on the wrong side of the planet for the eclipse, you can catch live webcasts from the following sites:
The Moon’s shadow stretches over the Earth in this balloon-mounted camera view of the November 14 solar eclipse (Catalin Beldea, Marc Ulieriu, Daniel Toma et. al/Stiinta&Tehnica)
On November 14, 2012, tens of thousands of viewers across northeastern Australia got a great view of one of the most awe-inspiring sights in astronomy — a total solar eclipse. Of course many fantastic photos and videos were taken of the event, but one team of high-tech eclipse hunters from Romania went a step further — or should I say higher — and captured the event from a video camera mounted on a weather balloon soaring over 36,800 meters (120,000 feet) up!
Their video can be seen below:
During a solar eclipse the Moon passes in front of the disk of the Sun, casting its shadow upon the Earth. Any viewers within the darkest part of the shadow — the umbra — will experience a total eclipse, while those within the wider, more diffuse shadow area along the perimeter — the penumbra — will see a partial eclipse.
By launching a weather balloon carrying a wide-angle camera into the stratosphere above Queensland, eclipse hunter and amateur astronomer Catalin Beldea, ROSA research scientist Florin Mingireanu and others on the team were able to obtain their incredible video of the November 14 total eclipse from high enough up that the shadow of the Moon was visible striking Earth’s atmosphere. Totality only lasted a couple of minutes so good timing was essential… but they got the shot. Very impressive!
The mission was organized by teams from the Romanian Space Agency (ROSA) and Stiinta&Tehnica.com, with the video assembled by Daniel Toma and posted on YouTube by editor-in-chief Marc Ulieriu. Music by Shamil Elvenheim.
The LROC turns to capture the Moon's shadow during the May 20 solar eclipse [NASA/GSFC/Arizona State University].
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The May 20 annular eclipse may have been an awesome sight for skywatchers across many parts of the Earth, but it was also being viewed by a robotic explorer around the Moon!
During the event NASA’s Lunar Reconnaissance Orbiter turned its camera to look back home, acquiring several images of the Earth with the Moon’s fuzzy shadow cast onto different regions during the course of the eclipse. The image above is a 4-panel zoom into one particular NAC image showing the Moon’s shadow over the Aleutian Islands.
LRO captured a total of four narrow-angle camera (NAC) images during two of its orbits. During one orbit the Moon’s shadow was over the southern part of Japan, and during the next it had moved northeast to cover the island chain of Alaska.
According to the LROC site run by Arizona State University:
The NAC is a line scanner, meaning that it has only one row of 5064 pixels per camera. Instead of snapping a single frame, an image is built up by the motion of the spacecraft in orbit about the Moon (about 1600 meters per second). To obtain an image of the Earth the spacecraft is turned 180° to face the Earth, then the spacecraft is pitched as quickly as possible (one-tenth of a degree per second), so that the image is built up line by line.
This also explains why some of the images are “clipped” on the edges… LRO ran out of time during its lunar orbit. Still, it’s great to be able to show some photos of the eclipse from quite possibly the most distant viewer anywhere!
Opportunity's shadow aims eastward to the rim of Endeavour crater
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The rover Opportunity captured a view into Endeavour crater as a low Sun cast a long shadow in this image, acquired back on March 9.
Endeavour is a large crater — 14 miles (22 km) wide, it’s about the same area as the city of Seattle. Opportunity arrived at its edge in August of 2011 after several years of driving across the Meridiani Plains.
Opportunity is currently the only operational manmade object on the surface of Mars… or any other planet besides Earth, for that matter. It’s a distinction it will hold until the arrival of Mars Science Laboratory at Gale Crater this August.
The scene is presented in false color to emphasize differences in materials such as dark dunes on the crater floor. This gives portions of the image an aqua tint.
Opportunity took most of the component images on March 9, 2012, while the solar-powered rover was spending several weeks at one location to preserve energy during the Martian winter. It has since resumed driving and is currently investigating a patch of windblown Martian dust near its winter haven.
Opportunity and its rover twin, Spirit, completed their three-month prime missions on Mars in April 2004. Both rovers continued for years of bonus, extended missions. Both have made important discoveries about wet environments on ancient Mars that may have been favorable for supporting microbial life. Spirit stopped communicating in 2010. Since landing in the Meridiani region of Mars in January 2004, Opportunity has driven 21.4 miles (34.4 kilometers).
Image credit: NASA/JPL-Caltech/Cornell/Arizona State University
The Moon's shadow falling over the Pacific on May 20, 2012
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As the annular eclipse on May 20 sent skywatchers around the globe gazing upwards to see the Sun get darkened by the Moon’s silhouette, NASA’s Terra satellite caught the other side of the event: the Moon’s shadow striking the Earth!
Cast across 240,000 miles of space, the lunar shadow darkened a circular swatch 300 km (185 miles) wide over the northern Pacific Ocean in this image, acquired by the Earth-observing Terra satellite’s Moderate Resolution Imaging Spectroradiometer (MODIS) at 20:30 UT on Sunday, May 20.
Where the Moon passed in front of the Sun, Earth’s surface appeared black (left half of image). Around the margins of the shadow, our planet’s surface appeared yellowish brown. The shadow cast by an eclipse consists of two parts, the completely shadowed umbra and the partially shadowed penumbra.
The eclipse was first visible over eastern Asia and moved across the globe, later becoming visible on the west coast of the US. Known as an annular eclipse, even in totality there was a bright ring of Sun visible around the Moon — a result of the Moon’s elliptical orbit. The effect was dramatic, and was captured in some amazing photos from viewers around the world (as well as by a few above the world!)
Looking at Earth during the Annular Solar Eclipse of May 20, 2012, photographed by Don Pettit from the International Space Station at 23:36 GMT. (NASA)
Although there were a few images being circulated online of the “eclipse” that were not actual photos, be assured that these are the real deal.
A lunar boulder peeks out into the sunlight. (NASA/GSFC/Arizona State University)
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A lunar boulder catches the last edge of the setting sunlight in this image from the Lunar Reconnaissance Orbiter Camera. The boulders litter the floor of an unnamed 3.5 km wide (2.17 mile wide) crater located within the much larger crater Lobachevskiy. The smaller crater’s rim casts its shadow along the left side of the image, and raises the question: why are shadows on the Moon so dark?
On Earth, air scatters light and allows objects not in direct sunlight to be still well-lit. This is an effect called Rayleigh scattering, named for the British Nobel-winning physicist Lord Rayleigh (John William Strutt.) Rayleigh scattering is the reason why the sky is blue, and (for the most part) why you can still read a magazine perfectly well under an umbrella at the beach.
On the Moon there is no air, no Rayleigh scattering. So shadows are very dark and, where sunlight hits, very bright. Shadowed areas are dramatically murky, like in the LROC image above, yet there’s still some light bouncing around in there — this is due to reflected light from the lunar surface itself.
Buzz was well-lit by reflected light, even in Eagle's shadow. (NASA/Apollo Image Archive)
Lunar regolith is composed of fine, angular particles of very reflective dust. It tends to reflect light directly back at the source, and will illuminate objects within shadows as well — as seen in Apollo mission photographs. Astronauts within the shadow of the landing modules were still visible, and their suits were well illuminated by reflected light from the lunar surface. Some people have used this as “proof” that the landings were actually filmed on a sound stage under artificial lights, but in reality it’s all due to reflected light.
So even though air isn’t scattering the sunlight on the Moon, there’s still enough reflection to sneak light into the shadows… but not much. It gets dark — and quickly cold — in there!
And if you’re one of those who likes to get a better look into the shadows, here’s the same image above with the dark areas brightened enough to see details:
Shadow world revealed! (NASA/GSFC/Arizona State University/J. Major)
Some interesting boulder trails in there!
See this image on Arizona State University’s LROC news page here, and zoom into the full NAC scan here.
