juliensimon/nasa-apod huggingface dataset:
Cosmic Crab Nebula (2014-07-25)

The Crab Pulsar, a city-sized, magnetized neutron star spinning 30 times a second, lies at the center of this tantalizing wide-field image of the Crab Nebula. A spectacular picture of one of our Milky Way's supernova remnants, it combines optical survey data with X-ray data from the orbiting Chandra Observatory. The composite was created as part of a celebration of Chandra's 15 year long exploration of the high energy cosmos. Like a cosmic dynamo the pulsar powers the X-ray and optical emission from the nebula, accelerating charged particles to extreme energies to produce the jets and rings glowing in X-rays. The innermost ring structure is about a light-year across. With more mass than the Sun and the density of an atomic nucleus, the spinning pulsar is the collapsed core of the massive star that exploded, while the nebula is the expanding remnant of the star's outer layers. The supernova explosion was witnessed in the year 1054.  Participate: Take an Aesthetics & Astronomy Survey
NGC 253: Dusty Island Universe (2014-07-26)

Shiny NGC 253 is one of the brightest spiral galaxies visible, and also one of the dustiest.  Some call it the Silver Dollar Galaxy for its appearance in small telescopes, or just the Sculptor Galaxy for its location within the boundaries of the southern constellation Sculptor.  First swept up in 1783 by mathematician and astronomer Caroline Herschel, the dusty island universe lies a mere 10 million light-years away. About 70 thousand light-years across, NGC 253 is the largest member of the Sculptor Group of Galaxies, the nearest to our own Local Group of Galaxies.  In addition to its spiral dust lanes, tendrils of dust seem to be rising from a galactic disk laced with young star clusters and star forming regions in this sharp color image. The high dust content accompanies frantic star formation, earning NGC 253 the designation of a starburst galaxy. NGC 253 is also known to be a strong source of high-energy x-rays and gamma rays, likely due to massive black holes near the galaxy's center.  Participate: Take an Aesthetics & Astronomy Survey

Image credit: László Francsics
Rho Ophiuchi Wide Field (2014-07-27)

The clouds surrounding the star system Rho Ophiuchi compose one of the closest star forming regions.  Rho Ophiuchi itself is a binary star system visible in the light-colored region on the image right. The star system, located only 400 light years away, is distinguished by its colorful surroundings, which include a red emission nebula and numerous light and dark brown dust lanes. Near the upper right of the Rho Ophiuchi molecular cloud system is the yellow star Antares, while a distant but coincidently-superposed globular cluster of stars, M4, is visible between Antares and the red emission nebula. Near the image bottom lies IC 4592, the Blue Horsehead nebula.  The blue glow that surrounds the Blue Horsehead's eye -- and other stars around the image -- is a reflection nebula composed of fine dust. On the above image left is a geometrically angled reflection nebula cataloged as Sharpless 1.  Here, the bright star near the dust vortex creates the light of surrounding reflection nebula. Although most of these features are visible through a small telescope pointed toward the constellations of Ophiuchus, Scorpius, and Sagittarius, the only way to see the intricate details of the dust swirls, as featured above, is to use a long exposure camera.

Image credit: Rogelio Bernal Andreo
The Horsehead Nebula from Blue to Infrared (2014-07-28)

One of the most identifiable nebulae in the sky, the Horsehead Nebula in Orion, is part of a large, dark, molecular cloud.  Also known as Barnard 33, the unusual shape was first discovered on a photographic plate in the late 1800s.  The red glow originates from hydrogen gas predominantly behind the nebula, ionized by the nearby bright star Sigma Orionis.  The darkness of the Horsehead is caused mostly by thick dust, although the lower part of the Horsehead's neck casts a shadow to the left.  Streams of gas leaving the nebula are funneled by a strong magnetic field.  Bright spots in the Horsehead Nebula's base are young stars just in the process of forming.  Light takes about 1,500 years to reach us from the Horsehead Nebula.  The above image is a digital combination of images taken in blue, green, red, and hydrogen-alpha light from the Argentina, and an image taken in infrared light by the orbiting Hubble Space Telescope.   Follow APOD on: Facebook,  Google Plus, or Twitter

Image credit: Optical: 
Aldo Mottino & Carlos Colazo, 
OAC, C�rdoba;
Infrared: Hubble Legacy Archive
A Sky Portal in New Zealand (2014-07-29)

To some, it may look like a portal into the distant universe. To others, it may appear as the eye of a giant. Given poetic license, both are correct. Pictured above is a standard fisheye view of the sky -- but with an unusual projection. The view is from a perch in  New Zealand called Te Mata Peak, a name that translates from the Maori language as "Sleeping Giant". The wondrous panorama shows the band of our Milky Way Galaxy right down the center of the sky, with the Large and Small Magellanic Clouds visible to the right. The red hue is atmospheric airglow that surprised the photographer as it was better captured by the camera than the eye.  The above image was taken two weeks ago as the photographer's sister, on the left, and an acquaintance  peered into the sky portal.

Image credit: Petr Hor�lek
M31: The Andromeda Galaxy (2014-07-30)

Andromeda is the nearest major galaxy to our own Milky Way Galaxy. Our Galaxy is thought to look much like Andromeda. Together these two galaxies dominate the Local Group of galaxies. The diffuse light from Andromeda is caused by the hundreds of billions of stars that compose it. The several distinct stars that surround Andromeda's image are actually stars in our Galaxy that are well in front of the background object. Andromeda is frequently referred to as M31 since it is the 31st object on Messier's list of diffuse sky objects. M31 is so distant it takes about two million years for light to reach us from there. Although visible without aid, the above image of M31 was taken with a standard camera through a small telescope. Much about M31 remains unknown, including how it acquired its unusual double-peaked center.

Image credit: Jacob Bers 
(Bersonic)
Veins of Heaven (2014-07-31)

Transfusing sunlight through a still dark sky, this exceptional display of noctilucent clouds was captured earlier this month above the island of Gotland, Sweden. From the edge of space, about 80 kilometers above Earth's surface, the icy clouds reflect sunlight even though the Sun itself is below the horizon as seen from the ground. Usually spotted at high latitudes in summer months the night shining clouds made a strong showing this July. Also known as polar mesopheric clouds they are understood to form as water vapor driven into the cold upper atmosphere condenses on the fine dust particles supplied by disintegrating meteors or volcanic ash. NASA's AIM mission provides daily projections of noctilucent clouds as seen from space.

Image credit: Clear Skies
Tetons and Snake River, Planet Earth (2014-08-01)

An alluring night skyscape, this scene looks west across the Grand Teton National Park, Wyoming, USA, Planet Earth. The Snake River glides through the foreground, while above the Tetons' rugged mountain peaks the starry sky is laced with exceptionally strong red and green airglow. That night, the luminous atmospheric glow was just faintly visible to the eye, its color and wavey structure captured only by a sensitive digital camera. In fact, this contemporary digital photograph matches the location and perspective of a well-known photograph from 1942 - The Tetons and The Snake River , by Ansel Adams, renowned photographer of the American West. Adams' image is one of 115 images stored on the Voyager Golden Record. Humanity's message in a bottle, golden records were onboard both Voyager 1 and Voyager 2 spacecraft, launched in 1977 and now headed toward interstellar space.

Image credit: Babak Tafreshi
NGC 7023: The Iris Nebula (2014-08-02)

These clouds of interstellar dust and gas have blossomed 1,300 light-years away in the fertile star fields of the constellation Cepheus. Sometimes called the Iris Nebula, NGC 7023 is not the only nebula in the sky to evoke the imagery of flowers, though. Still, this deep telescopic view shows off the Iris Nebula's range of colors and symmetries in impressive detail.  Within the Iris, dusty nebular material surrounds a hot, young star. The dominant color of the brighter reflection nebula is blue, characteristic of dust grains reflecting starlight. Central filaments of the dusty clouds glow with a faint reddish photoluminesence as some dust grains effectively convert the star's invisible ultraviolet radiation to visible red light. Infrared observations indicate that this nebula may contain complex carbon molecules known as PAHs. The pretty blue petals of the Iris Nebula span about six light-years.

Image credit: Jimmy Walker
Dark Shuttle Approaching (2014-08-03)

What's that approaching? Astronauts on board the International Space Station first saw it in early 2010 far in the distance.  Soon it enlarged to become a dark silhouette. As it came even closer, the silhouette appeared to be a spaceship. Finally, the object revealed itself to be the Space Shuttle Endeavour, and it soon docked as expected with the Earth-orbiting space station.  Pictured above, Endeavour was imaged near Earth's horizon as it approached, where several layers of the Earth's atmosphere were visible. Directly behind the shuttle is the mesosphere, which appears blue.  The atmospheric layer that appears white is the stratosphere, while the orange layer is Earth's Troposphere. This shuttle mission, began with a dramatic night launch. Tasks completed during this shuttle's visit to the ISS included the delivery of the Tranquility Module which contained a cupola bay window complex that allows even better views of spaceships approaching and leaving the space station.    Almost Hyperspace: Random APOD Generator
Shadows and Plumes Across Enceladus (2014-08-04)

Why does Enceladus have ice plumes? The discovery of jets spewing water vapor and ice was detected by the Saturn-orbiting Cassini spacecraft in 2005.  The origin of the water feeding the jets, however, remained a topic of research.  A leading hypothesis held that the source might originate from a deep underground sea, but another hypothesis indicated that it might just be ice melted off walls of deep rifts by the moon's tidal flexing and heating.  Pictured above, the textured surface of Enceladus is visible in the foreground, while rows of plumes rise from ice fractures in the distance.  These jets are made more visible by the Sun angle and the encroaching shadow of night. Recent study of over a hundred images like this -- of geysers crossing Enceladus' South Pole, together with regional heat maps,  indicate that these plumes likely originate from a hidden sea,  incresaing the chance that this frosty globe might be harboring life.    Astrophysicists: Browse 850+ codes in the Astrophysics Source Code Library
Four Billion BCE: Battered Earth (2014-08-05)

No place on Earth was safe. Four billion years ago, during the Hadean eon, our Solar System was a dangerous shooting gallery of large and dangerous rocks and ice chunks. Recent examination of lunar and Earth bombardment data indicate that the entire surface of the Earth underwent piecemeal upheavals, hiding our globe's ancient geologic history, and creating a battered world with no remaining familiar land masses.  The rain of devastation made it difficult for any life to survive, although bacteria that could endure high temperatures had the best chance. Oceans thought to have formed during this epoch would boil away after particularly heavy impacts, only to reform again.  The above artist's illustration depicts how Earth might have looked during this epoch, with circular impact features dotting the daylight side, and hot lava flows visible in the night.  One billion years later, in a calmer Solar System, Earth's first supercontinent formed.
Saturn's Swirling Cloudscape (2014-08-06)

Acquiring its first sunlit views of far northern Saturn in late 2012, the Cassini spacecraft's wide-angle camera recorded this stunning, false-color image of the ringed planet's north pole. The composite of near-infrared image data results in red hues for low clouds and green for high ones, giving the Saturnian cloudscape a vivid appearance. Enormous by terrestrial standards, Saturn's north polar hurricane-like storm is deep, red, and about 2,000 kilometers wide. Clouds at its outer edge travel at over 500 kilometers per hour. Other atmospheric vortices also swirl inside the large, yellowish green, six-sided jet stream known as the hexagon. Beyond the cloud tops at the upper right, arcs of the planet's eye-catching rings appear bright blue.
Rosetta's Rendezvous (2014-08-07)

On August 3rd, the Rosetta spacecraft's narrow angle camera captured this stunning image of the nucleus of Comet 67P/Churyumov-Gerasimenko. After 10 years and 6.5 billion kilometers of travel along gravity assist trajectories looping through interplanetary space, Rosetta had approached to within 285 kilometers of its target. The curious double-lobed shape of the nucleus is revealed in amazing detail at an image resolution of 5.3 meters per pixel. About 4 kilometers across, the comet nucleus is presently just over 400 million kilometers from Earth, between the orbits of Jupiter and Mars. Now the first spacecraft to achieve a delicate orbit around a comet, Rosetta will swing to within 50 kilometers and closer in the coming weeks, identifiying candidate sites for landing its probe Philae later this year.
Spiral Galaxy NGC 6744 (2014-08-08)

Big, beautiful spiral galaxy NGC 6744 is nearly 175,000 light-years across, larger than our own Milky Way. It lies some 30 million light-years distant in the southern constellation Pavo. We see the disk of the nearby island universe tilted towards our line of sight. Orientation and composition give a strong sense of depth to this colorful galaxy portrait that covers an area about the angular size of the full moon. This giant galaxy's yellowish core is dominated by the light from old, cool stars. Beyond the core, spiral arms filled with young blue star clusters and pinkish star forming regions sweep past a smaller satellite galaxy at the lower left, reminiscent of the Milky Way's satellite galaxy the Large Magellanic Cloud.

Image credit: Don Goldman
A Luminous Night (2014-08-09)

What shines in the world at night? Just visible to the eye, a rare electric blue glow spread along the shores of Victoria Lake on January 16, 2013. Against reflections of a light near the horizon, this digitally stacked long exposure recorded the bioluminescence of Noctiluca scintillans, plankton stimulated by the lapping waves. Above, the night skies of the Gippsland Lakes region, Victoria, Australia shine with a fainter greenish airglow. Oxygen atoms in the upper atmosphere, initially excited by ultraviolet sunlight, produce the more widely seen fading atmospheric chemiluminescence. Washed out by the Earth's rotation, the faint band of the southern summer Milky Way stretches from the horizon as star trails circle the South Celestial Pole.  Watch: Meteors vs. Supermoon

Image credit: Phil Hart
A Perseid Below (2014-08-10)

Denizens of planet Earth typically watch meteor showers by looking up. But this remarkable view, captured on August 13, 2011 by astronaut Ron Garan, caught a Perseid meteor by looking down. From Garan's perspective onboard the International Space Station orbiting at an altitude of about 380 kilometers, the Perseid meteors streak below, swept up dust left from comet Swift-Tuttle heated to incandescence. The glowing comet dust grains are traveling at about 60 kilometers per second through the denser atmosphere around 100 kilometers above Earth's surface. In this case, the foreshortened meteor flash is right of frame center, below the curving limb of the Earth and a layer of greenish airglow, just below bright star Arcturus. Want to look up at a meteor shower?  You're in luck, as the 2014 Perseids meteor shower peaks this week. Unfortunately, the fainter meteors in this year's shower will be hard to see in a relatively bright sky lit by the glow of a nearly full Moon.
Rosetta Approaches Comet Churyumov-Gerasimenko (2014-08-11)

What does it look like to approach a comet? Early this month humanity received a new rendition as the robotic Rosetta spacecraft went right up to -- and began orbiting -- the nucleus of Comet 67P/Churyumov-Gerasimenko. This approach turned out to be particularly fascinating because the comet nucleus first revealed itself to have an unexpected double structure, and later showed off an unusual and craggily surface.  The above 101-frame time-lapse video details the approach of the spacecraft from August 1 through August 6. The icy comet's core is the size of a mountain and rotates every 12.7 hours. Rosetta's images and data may shed light on the origin of comets and the early history of our Solar System. Later this year, Rosetta is scheduled to release the Philae lander, which will attempt to land on Comet Churyumov�Gerasimenko's periphery and harpoon itself to the surface.

Image credit: ESA
Collapse in Hebes Chasma on Mars (2014-08-12)

What's happened in Hebes Chasma on Mars? Hebes Chasma is a depression just north of the enormous Valles Marineris canyon.  Since the depression is unconnected to other surface features, it is unclear where the internal material went. Inside Hebes Chasma is Hebes Mensa, a 5 kilometer high mesa that appears to have undergone an unusual partial collapse -- a collapse that might be providing clues. The above image, taken by the robotic Mars Express spacecraft currently orbiting Mars, shows great details of the chasm and the unusual horseshoe shaped indentation in the central mesa. Material from the mesa appears to have flowed onto the floor of the chasm, while a possible dark layer appears to have pooled like ink on a downslope landing.  A recent hypothesis holds that salty rock composes some lower layers in Hebes Chasma, with the salt dissolving in melted ice flows that drained through holes into an underground aquifer.    Help APOD: Take the APOD 2014 Calendar Usage Poll

Image credit: ESA
Rings Around the Ring Nebula (2014-08-13)

It is a familiar sight to sky enthusiasts with even a small telescope. There is much more to the Ring Nebula (M57), however, than can be seen through a small telescope.  The easily visible central ring is about one light-year across, but this remarkably deep exposure - a collaborative effort combining data from three different large telescopes - explores the looping filaments of glowing gas extending much farther from the nebula's central star. This remarkable composite image includes narrowband hydrogen image, visible light emission, and infrared light emission. Of course, in this well-studied example of a planetary nebula, the glowing material does not come from planets. Instead, the gaseous shroud represents outer layers expelled from a dying, sun-like star. The Ring Nebula is about 2,000 light-years away toward the musical constellation Lyra.   Follow APOD on: Facebook,  Google Plus, or Twitter

Image credit: Robert Gendler
Surreal Moon (2014-08-14)

Big, bright, and beautiful, a Full Moon near perigee, the closest point in its elliptical orbit around our fair planet, rose on August 10. This remarkable picture records the scene with a dreamlike quality from the east coast of the United States. The picture is actually a composite of 10 digital frames made with exposures from 1/500th second to 1 second long, preserving contrast and detail over a much wider than normal range of brightness. At a perigee distance of a mere 356,896 kilometers, August's Full Moon was the closest, and so the largest and most super, of the three Full Moons nearest perigee in 2014 now popularly known as supermoons. But if you missed August's super supermoon, the next not-quite-so supermoon will be September 8. Then, near the full lunar phase the Moon's perigee will be a slightly more distant 358,387 kilometers. That's only about 0.4 percent less super (farther and smaller) than the super supermoon.

Image credit: Catching the Light
Perseid in Moonlight (2014-08-15)

Bright moonlight from a Full Moon near perigee illuminates the night and casts shadows in this skyscape from central Iran. Taken on August 12, near the peak of the annual Perseid meteor shower the exposure also captures a bright and colorful perseid streak above the shady tree in the foreground. This year the super moonlight interfered with meteor watching into the early morning hours, overwhelming the trails from many fainter perseids in the shower. Brighter perseids like this one were still visible though, their trails pointing back to the heroic constellation Perseus outlined at the right. Swept up as planet Earth orbits through dust left behind from periodic comet Swift-Tuttle, the cosmic grains that produce perseid meteors enter the atmosphere at nearly 60 kilometers per second, heated to incandesence and vaporized at altitudes of about 100 kilometers. Next year, Perseid meteors will flash through dark skies under a New Moon.  Editor's note: The outline of Perseus in the picture is close, but not quite right. A corrected version is available here, thanks to Wil Tirion.

Image credit: Amir Hossein Abolfath
No X-rays from SN 2014J (2014-08-16)

Last January, telescopes in observatories around planet Earth were eagerly used to watch the rise of SN 2014J, a bright supernova in nearby galaxy M82. Still, the most important observations may have been from orbit where the Chandra X-ray Observatory saw nothing. Identified as a Type Ia supernova, the explosion of SN2014J was thought to be triggered by the buildup of mass on a white dwarf star steadily accreting material from a companion star. That model predicts X-rays would be generated when the supernova blastwave struck the material left surrounding the white dwarf. But no X-rays were seen from the supernova. The mostly blank close-ups centered on the supernova's position are shown in the before and after inset panels of Chandra's false color X-ray image of the M82 galaxy. The stunning lack of X-rays from SN 2014J will require astronomers to explore other models to explain what triggers these cosmic explosions.
Jupiter and Venus from Earth (2014-08-17)

It was visible around the world. The sunset conjunction of Jupiter and Venus in 2012 was visible almost no matter where you lived on Earth.  Anyone on the planet with a clear western horizon at sunset could see them. Pictured above in 2012, a creative photographer traveled away from the town lights of Szubin, Poland to image a near closest approach of the two planets. The bright planets were separated only by three degrees and his daughter striking a humorous pose. A faint red sunset still glowed in the background. Early tomorrow (Monday) morning, the two planets will pass even closer -- only 0.2 degrees apart as visible from some locations -- just before sunrise.    Jump Around the Universe: Random APOD Generator
Star Trails Over Indonesia (2014-08-18)

Both land and sky were restless. The unsettled land included erupting Mount Semeru in the distance, the caldera of steaming Mount Bromo on the left, flowing fog, and the lights of moving cars along roads that thread between hills and volcanoes in Bromo Tengger Semeru National Park in East Java, Indonesia. The stirring sky included stars circling the South Celestial Pole and a meteor streaking across the image right. The above 270-image composite was taken from King Kong Hill in mid-June over two hours, with a rising Moon lighting the landscape.   Follow APOD on: Facebook,  Google Plus, or Twitter