juliensimon/nasa-apod huggingface dataset:
Volcano of Fire Erupts Under the Stars (2015-03-11)

First, there was an unusual smell. Then there was a loud bang. But what appeared to the eye was the most amazing of all. While waiting near midnight to see a possible eruption of Volc�n de Fuego (Volcano of Fire) in Guatemala last month, a ready camera captured this extraordinary image.  Lava is seen running down the side of the volcano, while ash rises up, and glowing magma bubbles explode out of the caldera. Lights near the town of Escuintla can be seen in the background, one of several nearby towns that have witnessed several spectacular eruptions previously.  High above, seemingly tranquil by comparison, are familiar stars from the night sky. Although the Volc�n de Fuego usually undergoes low-level activity, when the next spectacular eruption will occur is unknown.   Click Through the Universe: Random APOD Generator

Image credit: Diego Rizzo
Along the Cygnus Wall (2015-03-12)

The W-shaped ridge of emission featured in this vivid skyscape is known as the Cygnus Wall. Part of a larger emission nebula with a distinctive outline popularly called The North America Nebula, the cosmic ridge spans about 20 light-years. Constructed using narrowband data to highlight the telltale reddish glow from ionized hydrogen atoms recombining with electrons, the two frame mosaic image follows an ionization front with fine details of dark, dusty forms in silhouette. Sculpted by energetic radiation from the region's young, hot, massive stars, the dark shapes inhabiting the view are clouds of cool gas and dust with stars likely forming within. The North America Nebula itself, NGC 7000, is about 1,500 light-years away.

Image credit: Jimmy Walker
The Great Wall by Moonlight (2015-03-13)

Last Friday, an almost Full Moon rose as the Sun set, over this mountainous landscape north of Beijing, China. Also near apogee, the farthest point in its elliptical orbit around planet Earth, it was this year's smallest and faintest Full Moon. The Jiankou section of the Great Wall of China meanders through the scene, the ancient Great Wall itself the subject of an older-than-the-space-age myth that it would be visible to the eye when standing on the lunar surface. But even from low Earth orbit, the large scale artifact of human civilization is very difficult to identify. At its farthest from our fair planet, the Moon shines brightly in the twilight sky though, posing in the faint, pinkish band known as the antitwilight arch or the belt of Venus.

Image credit: Francis Audet
Return at Sunrise (2015-03-14)

Thursday, shortly after local sunrise over central Asia, this Soyuz spacecraft floated over a sea of golden clouds during its descent by parachute through planet Earth's dense atmosphere. On board were Expedition 42 commander Barry Wilmore of NASA and Alexander Samokutyaev and Elena Serova of the Russian Federal Space Agency (Roscosmos). Touch down was at approximately 10:07 p.m. EDT (8:07 a.m. March 12, Kazakh time) southeast of Zhezkazgan, Kazakhstan. The three were returning from low Earth orbit, after almost six months on the International Space Station as members of the Expedition 41 and Expedition 42 crews.
A Total Eclipse at the End of the World (2015-03-15)

Would you go to the end of the world to see a total eclipse of the Sun? If you did, would you be surprised to find someone else there already? In 2003, the Sun, the Moon, Antarctica, and two photographers all lined up in Antarctica during an unusual total solar eclipse.  Even given the extreme location, a group of enthusiastic eclipse chasers ventured near the bottom of the world to experience the surreal momentary disappearance of the Sun behind the Moon.  One of the treasures collected was the above picture -- a composite of four separate images digitally combined to realistically simulate how the adaptive human eye saw the eclipse.  As the image was taken, both the Moon and the Sun peeked together over an Antarctic ridge.  In the sudden darkness, the magnificent corona of the Sun became visible around the Moon.  Quite by accident, another photographer was caught in one of the images checking his video camera.   Visible to his left are an equipment bag and a collapsible chair.  A total solar eclipse will occur on Friday and be visible from the north Atlantic Ocean.

Image credit: Fred Bruenjes
(moonglow.net)
The Clouds of Orion the Hunter (2015-03-16)

Cradled in cosmic dust and glowing hydrogen, stellar nurseries in Orion the Hunter lie at the edge of giant molecular clouds some 1,500 light-years away. Spanning about 30 degrees, this breath-taking vista stretches across the well-known constellation from head to toe (left to right) and beyond. At 1,500 light years away, the Great Orion Nebula is the closest large star forming region, here visible just right and below center. To its left are the Horsehead Nebula, M78, and Orion's belt stars. Sliding your cursor over the picture will also find red giant Betelgeuse at the hunter's shoulder, bright blue Rigel at his foot, the Witch Head Nebula above -- and illuminated by -- Rigel, and the glowing Lambda Orionis (Meissa) nebula on the left, near Orion's head. Of course, the Orion Nebula and bright stars are easy to see with the unaided eye, but dust clouds and emission from the extensive interstellar gas in this nebula-rich complex, are too faint and much harder to record. In this mosaic of broadband telescopic images, additional image data acquired with a narrow hydrogen alpha filter was used to bring out the pervasive tendrils of energized atomic hydrogen gas like in the arc of the giant Barnard's Loop.

Image credit: Rogelio
Bernal Andreo
The Big Dipper Enhanced (2015-03-17)

Do you see it?  This common question frequently precedes the rediscovery of one of the most commonly recognized configurations of stars on the northern sky: the Big Dipper.  This grouping of stars is one of the few things that has likely been seen, and will be seen, by every human generation.   In this featured image, however, the stars of the Big Dipper have been digitally enhanced -- they do not really appear this much brighter than nearby stars.  The image was taken earlier this month from France. The Big Dipper is not by itself a constellation.  Although part of the constellation of the Great Bear (Ursa Major), the Big Dipper is an asterism that has been known by different names to different societies. Five of the Big Dipper stars are actually near each other in space and were likely formed at nearly the same time.  Relative stellar motions will cause the Big Dipper to slowly change its apparent configuration over the next 100,000 years.   Follow APOD on: Facebook,  Google Plus, or Twitter

Image credit: VegaStar Carpentier
Earth During a Total Eclipse of the Sun (2015-03-18)

What does the Earth look like during a total solar eclipse?  It appears dark in the region where people see the eclipse, because that's where the shadow of the Moon falls. The shadow spot actually shoots across the Earth at nearly 2,000 kilometers per hour, darkening locations in its path for only a few minutes before moving on. The featured image shows the Earth during the total solar eclipse of 2006 March, as seen from the International Space Station.  On Friday the Moon will move in front of the Sun once again, casting another distorted circular shadow that, this time, will zip over part of the north Atlantic Ocean.
Aurora in the Backyard (2015-03-19)

On the night of March 17/18 this umbrella of northern lights unfolded over backyards in Vallentuna, Sweden about 30 kilometers north of Stockholm. A result of the strongest geomagnetic storm of this solar cycle, auroral displays were captured on that night from back and front yards at even lower latitudes, including sightings in the midwestern United States. A boon for aurora hunting skywatchers, the space storm began building when a coronal mass ejection, launched by solar activity some two days earlier, struck planet Earth's magnetosphere. So what's the name of the backyard observatory on the right of the wide field view? That's Carpe Noctem Observatory, of course.

Image credit: Clear Skies
Sunshine, Earthshine (2015-03-20)

Today's date marks an Equinox and a New Moon. Remarkably, while the exact timing of both geocentric events occur within a span of only 13 hours, the moon also reaches its new phase only 14 hours after perigee, the closest point in its orbit. That makes the Equinox New Moon the largest New Moon of 2015, though hard to see since that lunar phase presents the Moon's dark, night side to planet Earth. Still, in this well composed image of a young lunar phase from late January you can glimpse both night and day on the lunar surface, the night side faintly illuminated by Earthshine next to the day side's brightly sunlit crescent. But some will see today's Equinox New Moon in silhouette! The Equinox Solar Eclipse will be total across stretches of the Arctic Ocean, visible in partial phases from Europe, northern Africa and western Asia.  Gallery: Today's solar eclipse
Northern Equinox Eclipse (2015-03-21)

Snowy and cold is weather you might expect at the start of spring for Longyearbyen on the Arctic archipelago of Svalbard, Norway. But that turned out to be good weather for watching the Moon's umbral shadow race across northern planet Earth. The region was plunged into darkness for 3 minutes during the March 20 total solar eclipse while insulated eclipse chasers witnessed the dark Sun in the cold clear sky. In this well-timed snapshot captured near the end of totality, the Moon's shadow sweeps away from the horizon and the solar corona fades as the lunar disk just begins to uncover the Sun. Streaming past the Moon's edge, direct rays of sunlight create the fleeting appearance of a glistening diamond ring.  Gallery: Solar Eclipse

Image credit: Stan Honda
A Double Eclipse of the Sun (2015-03-22)

Can the Sun be eclipsed twice at the same time? Last Friday was noteworthy because part of the Earth was treated to a rare total eclipse of the Sun. But also on Friday, from a part of the Earth that only saw part of the Sun eclipsed, a second object appeared simultaneously in front of the Sun: the Earth-orbiting International Space Station. Although space station eclipses are very quick -- in this case only 0.6 seconds, they are not so rare.  Capturing this composite image took a lot of planning and a little luck, as the photographer had to dodge a series of third objects that kept, annoyingly, also lining up in front of the Sun: clouds. The above superposed time-lapse sequence was taken from Fregenal de la Sierra in southern Spain. The dark disk of the Moon dominates the lower right, while the Sun's textured surface shows several filaments and, over an edge, a prominence.   Gallery: Solar Eclipse

Image credit: Thierry Legault
Atlas V Launches MMS (2015-03-23)

Birds don't fly this high.  Airplanes don't go this fast.  The Statue of Liberty weighs less.  No species other than human can even comprehend what is going on, nor could any human just a millennium ago. The launch of a rocket bound for space is an event that inspires awe and challenges description.  Pictured above, an Atlas V rocket lifts off carrying NASA's Magnetospheric Multiscale Mission into Earth orbit 10 days ago to study the workings of the magnetosphere that surrounds and protects the Earth. From a standing start, the 300,000 kilogram rocket ship left to circle the Earth where the outside air is too thin to breathe. Rockets bound for space are now launched from somewhere on Earth about once a week.

Image credit: Ben Cooper
(Launch Photography)
Powers of Ten (2015-03-24)

How different does the universe look on small, medium, and large scales?  The most famous short science film of its generation gives breathtaking comparisons. That film, Powers of Ten, originally created in the 1960s, has now been officially posted to YouTube and embedded above.  Please click the above arrow to see the nine minute movie for yourself.  From a picnic blanket near Chicago out past the Virgo Cluster of Galaxies, every ten seconds the film zooms out to show a square a factor of ten times larger on each side. The video then reverses, zooming back in a factor of ten every two seconds and ends up inside a single proton. The Powers of Ten sequence is actually based on the book Cosmic View by Kees Boeke in 1957, as is a similar but mostly animated film Cosmic Zoom that was also created in the late 1960s. The changing perspectives are so enthralling and educational that sections have been recreated using more modern computerized techniques, including the first few minutes of the movie Contact, and in a short digital video called The Known Universe created in 2010 for the American Museum of Natural History. Ray and husband Charles Eames, the film's creators, were known as quite visionary spirits and even invented their own popular chair.

Image credit: Charles & Ray Eames
(Eames Office)
Naked Eye Nova Sagittarii 2015 No. 2 (2015-03-25)

It quickly went from obscurity to one of the brighter stars in Sagittarius -- but it's fading.  Named Nova Sagittarii 2015 No. 2, the stellar explosion is the brightest nova visible from Earth in over a year.  The featured image was captured four days ago from Ranikhet in the Indian Himalayas.  Several stars in western Sagittarius make an asterism known as the Teapot, and the nova, indicated by the arrow, now appears like a new emblem on the side of the pot.  As of last night, Nova Sag has faded from brighter than visual magnitude 5 to the edge of unaided visibility. Even so, the nova should still be easily findable with binoculars in dark skies before sunrise over the next week.   Gallery: Solar Eclipse

Image credit: Ajay Talwar 
(The World at Night)
Orion Spring (2015-03-26)

As spring comes to planet Earth's northern hemisphere, familiar winter constellation Orion sets in early evening skies and budding trees frame the Hunter's stars. The yellowish hue of cool red supergiant Alpha Orionis, the great star Betelgeuse, mingles with the branches at the top of this colorful skyscape. Orion's alpha star is joined on the far right by Alpha Tauri. Also known as Aldebaran and also a giant star cooler than the Sun, it shines with a yellow light at the head of Taurus, the Bull. Contrasting blue supergiant Rigel, Beta Orionis, is Orion's other dominant star though, and marks the Hunter's foot below center. Of course, the sword of Orion hangs from the Hunter's three blue belt stars near picture center, but the middle star in the sword is not a star at all. A slightly fuzzy pinkish glow hints at its true nature, a nearby stellar nursery visible to the unaided eye known as the Orion Nebula.

Image credit: Bill Dickinson
NGC 2403 in Camelopardalis (2015-03-27)

Magnificent island universe NGC 2403 stands within the boundaries of the long-necked constellation Camelopardalis. Some 10 million light-years distant and about 50,000 light-years across, the spiral galaxy also seems to have more than its fair share of giant star forming HII regions, marked by the telltale reddish glow of atomic hydrogen gas. The giant HII regions are energized by clusters of hot, massive stars that explode as bright supernovae at the end of their short and furious lives. A member of the M81 group of galaxies, NGC 2403 closely resembles another galaxy with an abundance of star forming regions that lies within our own local galaxy group, M33 the Triangulum Galaxy. Spiky in appearance, bright stars in this colorful galaxy portrait of NGC 2403 lie in the foreground, within our own Milky Way.

Image credit: Martin Pugh
Diamond Rings and Baily's Beads (2015-03-28)

Near the March 20 equinox the cold clear sky over Longyearbyen, Norway, planet Earth held an engaging sight, a total eclipse of the Sun. The New Moon's silhouette at stages just before and after the three minute long total phase seems to sprout glistening diamonds and bright beads in this time lapse composite of the geocentric celestial event. The last and first glimpses of the solar disk with the lunar limb surrounded by the glow of the Sun's inner corona give the impression of a diamond ring in the sky. At the boundaries of totality, sunlight streaming through valleys in the irregular terrain along the Moon's edge, produces an effect known as Baily's Beads, named after English astronomer Francis Baily who championed an explanation for the phenomenon in 1836. This sharp composition also shows off the array of pinkish solar prominences lofted above the edge of the eclipsed Sun.

Image credit: Wang, Letian
Shadow of a Martian Robot (2015-03-29)

What if you saw your shadow on Mars and it wasn't human?  Then you might be the Opportunity rover currently exploring Mars.  Opportunity has been exploring the red planet since early 2004, finding evidence of ancient water, and sending breathtaking images across the inner Solar System.  Pictured above in 2004, Opportunity looks opposite the Sun into Endurance Crater and sees its own shadow.  Two wheels are visible on the lower left and right, while the floor and walls of the unusual crater are visible in the background.  Opportunity is continuing on its long trek exploring unusual terrain in Meridiani Planum which continues to yield clues to the ancient history of Mars, our Solar System, and even humanity.
A Flag Shaped Aurora over Sweden (2015-03-30)

It appeared, momentarily, like a 50-km tall banded flag.  In mid-March, an energetic Coronal Mass Ejection directed toward a clear magnetic channel to Earth led to one of the more intense geomagnetic storms of recent years. A visual result was wide spread auroras being seen over many countries near Earth's magnetic poles.  Captured over Kiruna, Sweden, the image features an unusually straight auroral curtain with the green color emitted low in the Earth's atmosphere, and red many kilometers higher up. It is unclear where the rare purple aurora originates, but it might involve an unusual blue aurora at an even lower altitude than the green, seen superposed with a much higher red.  As the Sun continues near its top level of surface activity, colorful nights of auroras over Earth are likely to continue.    Follow APOD on: Facebook,  Google Plus, or Twitter

Image credit: Mia St�lnacke
Corona from Svalbard (2015-03-31)

During a total solar eclipse, the Sun's extensive outer atmosphere, or corona, is an inspirational sight. Streamers and shimmering features that engage the eye span a brightness range of over 10,000 to 1, making them notoriously difficult to capture in a single photograph. But this composite of 29 telescopic images covers a wide range of exposure times to reveal the crown of the Sun in all its glory. The aligned and stacked digital frames were recorded in the cold, clear skies above the Arctic archipelago of Svalbard, Norway during the Sun's total eclipse on March 20 and also show solar prominences extending just beyond the edge of the solar disk. Remarkably, even small details on the dark night side of the New Moon can be made out, illuminated by sunlight reflected from a Full Earth. Of course, fortunes will be reversed on April 4 as a Full Moon plunges into the shadow of a New Earth, during a total lunar eclipse.

Image credit: Miloslav
Druckmüller
Suiting Up for the Moon (2015-04-01)

How will cows survive on the Moon?  One of the most vexing questions asked about space, scientists have spent decades debating this key issue.  Finally, after extensive computer modeling and over a dozen midnight milkings, engineers have designed, built, and now tested the new Lunar Grazing Module (LGM), a multi-purpose celestial bovine containment system.  By now, many of you will not be surprised to be wished a Happy April Fool's Day from APOD.  To the best of our knowledge, there are no current plans to launch cows into space.  For one reason, cows tend to be large animals that don't launch easily or cheaply. As friendly as cows may be, head-to-head comparisons show that robotic rovers are usually more effective as scientific explorers. The featured image is of a thought-provoking work of art named "Mooooonwalk" which really is on display at a popular science museum.

Image credit: Robert Nemiroff
(Michigan Tech. U.)
The Owl and the Galaxy (2015-04-02)

The Owl and the Galaxy sail these skies With blue and yellow star. They go together beneath the Big Dipper, If you wonder where they are.  The Galaxy's light shines through the night, Ten millions of light-years away. But never fear the Owl is near, Inside the Milky Way. A cosmic shroud, the Owl is proud, its central star a must. And the spiral Galaxy lies on edge To show off all its dust, Its dust, Its dust, To show off all its dust.

Image credit: Christoph Kaltseis
Sun and Moon Halo (2015-04-03)

Two pictures captured on April 1 are combined in this creative day and night composite. Separated in time by about 10 hours the images otherwise match, looking along the coast at Östersund Sweden. The relative times were chosen to show the Sun and a nearly full Moon at the same place in the cold, early springtime sky. In the night scene Jupiter also shines above the waterfront lights, while Sun and Moon are both surrounded by a beautiful circular ice halo. The Sun and Moon halos really do align, each with an angular radius of 22 degrees. That radius is a constant, not determined by the brightness of Sun or Moon but only by the hexagonal geometry of atmospheric ice crystals and the reflection and refraction of light. Of course tomorrow, April 4, will find the Sun and Moon on opposite sides of planet Earth for a total lunar eclipse.

Image credit: Göran Strand
Voorwerpjes in Space (2015-04-04)

Mysterious Hanny's Voorwerp, Dutch for "Hanny's Object", is really enormous, about the size of the Milky Way Galaxy and glowing strongly in the greenish light produced by ionized oxygen atoms. It is thought to be a tidal tail of material left by an ancient galaxy merger, illuminated and ionized by the outburst of a quasar inhabiting the center of distant spiral galaxy IC 2497. Its exciting 2007 discovery by Dutch schoolteacher Hanny van Arkel while participating online in the Galaxy Zoo project has since inspired a search and discovery of eight more eerie green cosmic features.  Imaged in these panels by the Hubble Space Telescope, all eight appear near galaxies with energetic cores. Far outside their associated galaxies, these objects are also likely echoes of quasar activity, illuminated only as light from a core quasar outburst reaches them and ultimately fading tens of thousands of years after the quasar outburst itself has faded away. Of course a galaxy merger like the impending merger of our own Milky Way and the Andromeda Galaxy, could also trigger the birth of a quasar that would illuminate our distant future version of Hanny's Voorwerp.
Saturn, Tethys, Rings, and Shadows (2015-04-05)

Seen from ice moon Tethys, rings and shadows would display fantastic views of the Saturnian system. Haven't dropped in on Tethys lately? Then this gorgeous ringscape from the Cassini spacecraft will have to do for now. Caught in sunlight just below and left of picture center in 2005, Tethys itself is about 1,000 kilometers in diameter and orbits not quite five saturn-radii from the center of the gas giant planet. At that distance (around 300,000 kilometers) it is well outside Saturn's main bright rings, but Tethys is still one of five major moons that find themselves within the boundaries of the faint and tenuous outer E ring. Discovered in the 1980s, two very small moons Telesto and Calypso are locked in stable locations along Tethys' orbit. Telesto precedes and Calypso follows Tethys as the trio circles Saturn.