juliensimon/nasa-apod huggingface dataset:
NGC 3521 Close Up (2011-01-13)

Gorgeous spiral galaxy NGC 3521 is a mere 35 million light-years distant, toward the constellation Leo. Spanning some 50,000 light-years, its central region is shown in this dramatic image, constructed from data drawn from the Hubble Legacy Archive. The close-up view highlights this galaxy's characteristic multiple, patchy, irregular spiral arms laced with dust and clusters of young, blue stars. In contrast, many other spirals exhibit grand, sweeping arms. A relatively bright galaxy in planet Earth's sky, NGC 3521 is easily visible in small telescopes, but often overlooked by amateur imagers in favor of other Leo spiral galaxies, like M66 and M65.
Quadrantids over Qumis (2011-01-14)

The Quadrantid Meteor Shower is an annual event for planet Earth's northern hemisphere skygazers. It usually peaks briefly in the cold, early morning hours of January 4. The shower is named for its radiant point on the sky within the old, astronomically obsolete constellation Quadrans Muralis. That position is situated near the boundaries of the modern constellations Hercules, Bootes, and Draco. In this haunting time exposure, two quadrantid meteor streaks are captured crossing trails left by rising stars of the constellations Virgo and Corvus, but Saturn leaves the brightest "star" trail. The meteor streaks, one bright and one faint, are nearly parallel above and right of center in the frame. Fittingly, the old cistern structure in the foreground lies above the now buried city of Qumis. Known as a city of many gates, Qumis (in Greek history Hecatompylos), was founded 2300 years ago in ancient Persia.

Image credit: Babak Tafreshi
A Total Eclipse at the End of the World (2011-01-15)

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 peaked 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.

Image credit: Fred Bruenjes
(moonglow.net)
Globular Star Cluster 47 Tuc (2011-01-16)

Globular star cluster 47 Tucanae is a jewel of the southern sky. Also known as NGC 104, it roams the halo of our Milky Way Galaxy along with some 200 other globular star clusters. The second brightest globular cluster (after Omega Centauri) as seen from planet Earth, it lies about 13,000 light-years away and can be spotted naked-eye near the Small Magellanic Cloud in the constellation of the Toucan. The dense cluster is made up of several million stars in a volume only about 120 light-years across. Red giant stars on the outskirts of the cluster are easy to pick out as yellowish stars in this sharp telescopic portrait. Globular cluster 47 Tuc is also home to exotic x-ray binary star systems.

Image credit: Dieter Willasch
Night and Day above Almost Planet Sounio (2011-01-17)

Has a new planet been discovered?   What is pictured above is a remarkable 24 hour mosaic surrounding a spot on Sounio, Greece, right here on planet Earth. Images taken at night compose the top half of the picture, with star trails lasting as long as 11 hours visible.  Contrastingly, images taken during the day compose the bottom of the image, with the Sun being captured once every 15 minutes.  The image center shows a Little Prince wide angle projection centered on the ground but including gravel, grass, trees, Saint John's church, clouds, crepuscular rays, and even a signature icon of the photographer -- the Temple of Poseidon. Meticulous planning as well as several transition shots and expert digital processing eventually culminated in this image documenting half of the final two days of last year.

Image credit: Chris Kotsiopoulos
Kona Galaxy Garden (2011-01-18)

How does your galaxy grow?  Quite contrary to a typical galaxy, this one needs water to flourish. Pictured above as it appears at the Paleaku Peace Gardens Sanctuary in Kona, Hawaii, USA, a meticulously planned garden spanning about 30 meters provides a relatively accurate map of our Milky Way Galaxy.  Different plants depict stars, globular clusters, and even nebulas. Many bright stars visible in Earth's night sky are depicted on leaves surrounding the marked location of the Sun. Plant rows were placed to represent arms of our Galaxy, including the Sun's Orion Arm, the impressive Sagittarius Arm, and the little discussed Norma Arm. A small bar runs through our Galaxy's center, while a fountain has been built to represent the central black hole. What a stellar use of space!

Image credit: Garden by Jon Lomberg; Kite Aerial Photography by Pierre and Heidy Lesage
Saturn Storm (2011-01-19)

Late last year, a new, remarkably bright storm erupted in Saturn's northern hemisphere. Amateur astronomers first spotted it in early December, with the ringed gas giant rising in planet Earth's predawn sky. Orbiting Saturn, the Cassini spacecraft was able to record this close-up of the complex disturbance from a distance of 1.8 million kilometers on December 24th. Over time, the storm has evolved, spreading substantially in longitude, and now stretches far around the planet. Saturn's thin rings are also seen slicing across this space-based view, casting broad shadows on the planet's southern hemisphere.
The Once and Future Stars of Andromeda (2011-01-20)

The big, beautiful Andromeda Galaxy, aka M31, is a spiral galaxy a mere 2.5 million light-years away. Two space-based observatories have combined to produce this intriguing composite image of Andromeda, at wavelengths outside the visible spectrum. The remarkable view follows the locations of this galaxy's once and future stars. In reddish hues, image data from the large Herschel infrared observatory traces enormous lanes of dust, warmed by stars, sweeping along Andromeda's spiral arms. The dust, in conjunction with the galaxy's interstellar gas, comprises the raw material for future star formation. X-ray data from the XMM-Newton observatory in blue pinpoint Andromeda's X-ray binary star systems. These systems likely contain neutron stars or stellar mass black holes that represent final stages in stellar evolution. More than twice the size of our own Milky Way, the Andromeda Galaxy is over 200,000 light-years across.
Alnitak, Alnilam, Mintaka (2011-01-21)

Alnitak, Alnilam, and Mintaka, are the bright bluish stars from east to west (left to right) along the diagonal in this gorgeous cosmic vista. Otherwise known as the Belt of Orion, these three blue supergiant stars are hotter and much more massive than the Sun. They lie about 1,500 light-years away, born of Orion's well-studied interstellar clouds. In fact, clouds of gas and dust adrift in this region have intriguing and some surprisingly familiar shapes, including the dark Horsehead Nebula and Flame Nebula near Alnitak at the lower left. The famous Orion Nebula itself lies off the bottom of this colorful star field. Recorded last December with a modified digital SLR camera and small telescope, the well-planned, two frame mosaic spans about 4 degrees on the sky.

Image credit: Sergi Verdugo
Martínez
Polar Ring Galaxy NGC 660 (2011-01-22)

NGC 660 lies near the center of this intriguing skyscape, swimming in the boundaries of the constellation Pisces. Over 20 million light-years away, its peculiar appearance marks it as a polar ring galaxy. A rare galaxy type, polar ring galaxies have a substantial population of stars, gas, and dust orbiting in rings nearly perpendicular to the plane of the galactic disk. The bizarre configuration could have been caused by the chance capture of material from a passing galaxy by the disk galaxy, with the captured debris strung out in a rotating ring. The polar ring component can be used to explore the shape of the galaxy's otherwise unseen dark matter halo by calculating the dark matter's gravitational influence on the rotation of the ring and disk. Broader than the disk, NGC 660's ring spans about 40,000 light-years.

Image credit: Stephen Leshin
Peekskill Fireball Video: Johnstown (2011-01-23)

The Peekskill meteor of 1992 was captured on 16 independent videos and then struck a car.  Documented as brighter than the full Moon, the spectacular fireball crossed parts of several USA states during its 40 seconds of glory before landing in New York.  A video of the fireball beyond a high school football game in Johnstown, Pennsylvania, USA, is pictured above. The resulting meteorite is imaged here, and was found to be composed of dense rock and has the size and mass of an extremely heavy bowling ball.  If you are lucky enough to find a meteorite just after impact, do not pick it up -- parts of it are likely to be either very hot or very cold.  Tracking meteors origins and destinations might be easier in this modern digital age, but many security cameras videos that likely caught a bright fireball are not preserved. If you would like to volunteer to help meteor science by locating images and videos of newly occurring fireballs within 48 hours after they occur, here is a place to sign up.   Students: See lectures on strange and cool physics
Phobos' South Pole from Mars Express (2011-01-24)

Where on this moon would you land? The moon pictured above is not Earth's moon but Phobos, the closest moon to the planet Mars.  Phobos is so close to Mars that it is expected to break up and crash into the red planet within the next 100 million years. Earlier just this year, however, ESA's Mars Express mission took detailed images of the area surrounding Phobos' South Pole. Visible on the small moon's unusually dark surface are many circular craters, long chains of craters, and strange streaks.   Large Stickney Crater, which looms on the far right, was also visible in the corresponding North Polar image taken last year.  This and other similar images of Phobos are so detailed, resolving items even 10-meters across, that they are useful for examining proposed landing sites of the future Phobos-Grunt mission. The Russian Phobos-Grunt robotic spacecraft is scheduled to launch toward Phobos later this year and return surface samples in 2014.    Vote: Astronomy Picture of the Year 2010

Image credit: ESA/DLR/FU Berlin 
(G. Neukum)
The Rippled Red Ribbons of SNR 0509 (2011-01-25)

What is causing the picturesque ripples of supernova remnant SNR 0509-67.5? The ripples, as well as the greater nebula, were imaged in unprecedented detail by the Hubble Space Telescope in 2006 and again late last year.  The red color was recoded by a Hubble filter that left only the light emitted by energetic hydrogen. The precise reason for the ripples remains unknown, with two considered origin hypotheses relating them to relatively dense portions of either ejected or impacted gas.  The reason for the broader red glowing ring is more clear, with expansion speed and light echos relating it to a classic Type Ia supernova explosion that must have occurred about 400 years earlier. SNR 0509 currently spans about 23 light years and lies about 160,000 light years away toward the constellation of the dolphinfish (Dorado) in the Large Magellanic Cloud. The expanding ring carries with it another great mystery, however: why wasn't this supernova seen 400 years ago when light from the initial blast should have passed the Earth?   Like: Follow APOD on Facebook
The Whirlpool Galaxy in Infrared Dust (2011-01-26)

How do spiral galaxies form stars? To help find out, the Hubble Space Telescope imaged the nearby photogenic spiral M51 in infrared light to highlight the dust that traces the dense gas that best forms stars. To further isolate the dust, much of the optical light from stars has also been digitally removed.  The resulting unique image shows swirling and intricate patterns on the longest scales, while numerous bright clumps of previously hidden open star clusters appear on the smaller scales. To see the detailed optical light image for comparison, run your cursor over the above image. Anyone with a good pair of binoculars can see the Whirlpool toward the constellation of the Hunting Dogs (Canes Venatici).  M51 lies about 30 million light years away, while the above imaged area spans about 15,000 light years from top to bottom. Astronomers speculate that M51's spiral structure is primarily due to its gravitational interaction with a neighboring smaller galaxy.   Browse: See the latest images submitted to APOD
Hidden Treasures of M78 (2011-01-27)

M78 isn't really hiding in planet Earth's night sky. About 1,600 light-years away and nestled in the nebula rich constellation Orion, the large, bright, reflection nebula is well-known to telescopic skygazers. But this gorgeous image of M78 was selected as the winner of the Hidden Treasures 2010 astrophotography competition. Held by the European Southern Observatory (ESO), the competition challenged amateur astronomers to process data from ESO's astronomical archive in search of cosmic gems. The winning entry shows off amazing details within bluish M78 (center) embraced in dark, dusty clouds, along with a smaller reflection nebula in the region, NGC 2071 (top). Yellowish and even more compact, the recently discovered, variable McNeil's Nebula is prominent in the scene below and right of center. Based on data from ESO's WFI camera and 2.2 meter telescope at La Silla, Chile, this image spans just over 0.5 degrees on the sky. That corresponds to 15 light-years at the estimated distance of M78.
NanoSail-D (2011-01-28)

Featured in this artist's illustration, NASA's NanoSail-D finally unfurled a very thin, 10 square meter reflective sail on January 20th, becoming the first solar sail spacecraft in low Earth orbit. Often considered the stuff of science fiction, sailing through space was suggested 400 years ago by astronomer Johannes Kepler who observed comet tails blown by the solar wind. Modern solar sail spacecraft designs, like NanoSail-D or the Japanese interplanetary spacecraft IKAROS, rely on the small but continuous pressure from sunlight itself for thrust. Glinting in the sunlight as it circles planet Earth, the NanoSail-D solar sail will periodically be bright and easily visible to the eye. In fact, skygazers are urged to participate in an ongoing contest to capture images of NanoSail-D. The images will help NASA monitor the satellite before it reenters the atmosphere in April or May.
Opportunity at Santa Maria Crater (2011-01-29)

Celebrating 7 years on the surface of the Red Planet, Mars exploration rover Opportunity now stands near the rim of 90 meter wide Santa Maria crater. Remarkably, Opportunity and its fellow rover Spirit were initially intended for a 3 month long primary mission. Still exploring, the golf cart-sized robot and shadow (far right) appear in the foreground of this panoramic view of its current location. The mosaic was constructed using images from the rover's navigation camera. On its 7 year anniversary, Opportunity can boast traversing a total of 26.7 kilometers along the martian surface. After investigating Santa Maria crater, controllers plan to have Opportunity resume a long-term trek toward Endeavour crater, a large, 22 kilometer diameter crater about 6 kilometers from Santa Maria. The rim of Endeavour is visible in the mosaic on the horizon at the right, just above the shadow of the rover's mast. During coming days, communication with the rover will be more difficult as Mars moves close to alignment with the Sun as seen from planet Earth's perspective.
Gibbous Europa (2011-01-30)

Although the phase of this moon might appear familiar, the moon itself might not. In fact, this gibbous phase shows part of Jupiter's moon Europa. The robot spacecraft Galileo captured this image mosaic during its mission orbiting Jupiter from 1995 - 2003. Visible are plains of bright ice, cracks that run to the horizon, and dark patches that likely contain both ice and dirt. Raised terrain is particularly apparent near the terminator, where it casts shadows. Europa is nearly the same size as Earth's Moon, but much smoother, showing few highlands or large impact craters. Evidence and images from the Galileo spacecraft, indicated that liquid oceans might exist below the icy surface. To test speculation that these seas hold life, NASA and ESA have started preliminary development of the Europa Jupiter System Mission, a spacecraft proposed for launch around 2020 that would further explore Jupiter and in particular Europa.  If the surface ice is thin enough, a future mission might drop hydrobots to burrow into the oceans and search for life.   Browse: See the latest images submitted to APOD

Image credit: reprocessed by Ted Stryk
Japan's Kounotori2 Supply Ship Approaches the Space Station (2011-01-31)

The care package from Earth had arrived. Last week, Japan launched the robotic Kounotori2 spacecraft to bring needed supplies, including food, to the International Space Station (ISS).  Kountori2 launched from Japan's Tanegashima Space Center a little over a week ago reached the ISS in low Earth late last week.  Pictured above, Kountori2 approached the ISS and was about to be grabbed by astronauts with the Canadarm2 and attached to the Harmony Module. In the above picture as seen through a window on the ISS, the limb of the Earth is visible, including white clouds, blue water, and various tan colored landforms.  In addition to launches including humans, as many as ten robotic spacecraft may be launched to the space station this year, potentially including spacecraft from Russia, Europe, Japan, and a private company in the USA.   Quiz: Can you identify which part of Earth is pictured?
Powers of Ten (2011-02-01)

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 last year 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)
Moon and Venus Over Switzerland (2011-02-02)

Sometimes a morning sky can be a combination of serene and surreal.  Such a sky perhaps existed before sunrise this past Sunday as viewed from a snowy slope in eastern Switzerland.  Quiet clouds blanket the above scene, lit from beneath by lights from the village of Tr�bbach.  A snow covered mountain, Mittlerspitz, poses dramatically on the upper left, hovering over the small town of Balzers, Liechtenstein far below.  Peaks from the Alps can be seen across the far right, just below the freshly rising Sun. Visible on the upper right are the crescent Moon and the bright planet Venus. Venus will remain in the morning sky all month, although it will likely not be found in such a photogenic setting.    Poll: Which of last week's APODs should be the APOW?

Image credit: David Kaplan
Six Worlds for Kepler-11 (2011-02-03)

Six worlds orbit Kepler-11, a sunlike star 2,000 light-years distant in the constellation Cygnus. The new discovery is based on data from NASA's planet hunting Kepler spacecraft. Compared to our Solar System in this illustration, five of Kepler-11's planets orbit closer to their parent star than the Mercury-Sun distance, with orbital periods ranging from 10 to 47 days. All six are larger than Earth and are likely composed of mixtures of rocky material and gas. Their presence, sizes, and masses have been determined by carefully watching the planets dim the light of Kepler-11 while transiting or crossing in front of the star itself. In fact, in August 2010, Kepler's telescope and camera recorded a simultaneous transit of three of the planets in the system. As announced yesterday, using the transit technique the Kepler mission has now identified over 1200 exoplanet candidates in a field of view that covers only about 1/400th of the sky. The tantalizing result suggests there are many undiscovered planets orbiting the stars in our galaxy.
Zeta Oph: Runaway Star (2011-02-04)

Like a ship plowing through cosmic seas, runaway star Zeta Ophiuchi produces the arcing interstellar bow wave or bow shock seen in this stunning infrared portrait from the WISE spacecraft. In the false-color view, bluish Zeta Oph, a star about 20 times more massive than the Sun, lies near the center of the frame, moving toward the top at 24 kilometers per second. Its strong stellar wind precedes it, compressing and heating the dusty interstellar material and shaping the curved shock front. Around it are clouds of relatively undisturbed material. What set this star in motion? Zeta Oph was likely once a member of a binary star system, its companion star was more massive and hence shorter lived. When the companion exploded as a supernova catastrophically losing mass, Zeta Oph was flung out of the system. About 460 light-years away, Zeta Oph is 65,000 times more luminous than the Sun and would be one of the brighter stars in the sky if it weren't surrounded by obscuring dust. The WISE image spans about 1.5 degrees or 12 light-years at the estimated distance of Zeta Ophiuchi.
Apollo 14: A View from Antares (2011-02-05)

Forty years ago, while looking out the window of Apollo 14's Lunar Module Antares, astronaut Ed Mitchell snapped a series of photos of the lunar surface, assembled into this detailed mosaic by Apollo Lunar Surface Journal editor Eric Jones. The view looks across the Fra Mauro highlands to the northwest of the landing site after the Apollo 14 astronauts had completed their second and final walk on the Moon. Prominent in the foreground is their Modular Equipment Transporter (MET), a two-wheeled, rickshaw-like device used to carry tools and samples. Near the horizon at top center is a 1.5 meter wide boulder dubbed Turtle rock. In the shallow crater below Turtle rock is the long white handle of a sampling instrument, thrown there javelin-style by Mitchell. Mitchell's fellow moonwalker and first American in space, Alan Shepard, also used a makeshift six iron to hit two golf balls. One of Shepard's golf balls is just visible as a white spot below Mitchell's javelin.