juliensimon/nasa-apod huggingface dataset:
Infrared Orion from WISE (2015-01-19)

The Great Nebula in Orion is an intriguing place.  Visible to the unaided eye, it appears as a small fuzzy patch in the constellation of Orion. But this image, an illusory-color four-panel mosaic taken in different bands of infrared light with the Earth orbiting WISE observatory, shows the Orion Nebula to be a bustling  neighborhood of recently formed stars, hot gas, and dark dust.  The power behind much of the Orion Nebula (M42) is the stars of the Trapezium star cluster, seen near the center of the above wide field image. The orange glow surrounding the bright stars pictured here is their own starlight reflected by intricate dust filaments that cover much of the region.  The current  Orion Nebula cloud complex, which includes the Horsehead Nebula, will slowly disperse over the next 100,000 years.   Now Available: APOD 2015 Wall Calendars

Image credit: :
Francesco Antonucci
Approaching Asteroid Ceres (2015-01-20)

It is the largest asteroid in the asteroid belt -- what secrets does it hold?  To find out, NASA has sent the robotic Dawn spacecraft to explore and map this cryptic 1,000-kilometer wide world: Ceres.  Orbiting between Mars and Jupiter, Ceres is officially categorized as a dwarf planet but has never been imaged in detail. Featured here is a 20-frame video taken a week ago of Dawn's approach that now rivals even the best images of Ceres ever taken by the Hubble Space Telescope. The video shows enough surface definition to discern its 9-hour rotation period. On target to reach Ceres in early March, Dawn will match speeds and attempt to orbit this previously unexplored body, taking images and data that may help humanity better understand not only the nature and history of Ceres but also the early history of our entire Solar System.
The Complex Ion Tail of Comet Lovejoy (2015-01-21)

What causes the structure in Comet Lovejoy's tail?  Comet C/2014 Q2 (Lovejoy), which is currently at naked-eye brightness and near its brightest, has been showing an exquisitely detailed ion tail.  As the name implies, the ion tail is made of ionized gas -- gas energized by ultraviolet light from the Sun and pushed outward by the solar wind.  The solar wind is quite structured and sculpted by the Sun's complex and ever changing magnetic field. The effect of the variable solar wind combined with different gas jets venting from the comet's nucleus accounts for the tail's complex structure.  Following the wind, structure in Comet Lovejoy's tail can be seen to move outward from the Sun even alter its wavy appearance over time.  The blue color of the ion tail is dominated by recombining carbon monoxide molecules, while the green color of the coma surrounding the head of the comet is created mostly by a slight amount of recombining diatomic carbon molecules.  The featured three-panel mosaic image was taken nine days ago from the IRIDA Observatory in Bulgaria.  Comet Lovejoy made it closest pass to the Earth two weeks ago and will be at its closest to the Sun in about ten days.  After that, the comet will fade as it heads back into the outer Solar System, to return only in about 8,000 years.   Astrophysicists: Browse 950+ codes in the Astrophysics Source Code Library

Image credit: Velimir Popov & Emil Ivanov  
(IRIDA Observatory)
Launch to Lovejoy (2015-01-22)

Blasting skyward an Atlas V rocket carrying a U.S. Navy satellite pierces a cloud bank in this starry night scene captured on January 20. On its way to orbit from Space Launch Complex 41, Cape Canaveral Air Force Station, planet Earth, the rocket streaks past brightest star Sirius, as seen from a dark beach at Canaveral National Seashore. Above the alpha star of Canis Major, Orion the Hunter strikes a pose familiar to northern winter skygazers. Above Orion is the V-shaped Hyades star cluster, head of Taurus the Bull, and farther still above Taurus it's easy to spot the compact Pleiades star cluster. Of course near the top of the frame you'll find the greenish coma and long tail of Comet Lovejoy, astronomical darling of these January nights.

Image credit: Lynn Hilborn
Interior View (2015-01-23)

Some prefer windows, and these are the best available on board the International Space Station. Taken on January 4, this snapshot from inside the station's large, seven-window Cupola module also shows off a workstation for controlling Canadarm2. Used to grapple visiting cargo vehicles and assist astronauts during spacewalks, the robotic arm is just outside the window at the right. The Cupola itself is attached to the Earth-facing or nadir port of the station's Tranquility module, offering dynamic panoramas of our fair planet. Seen from the station's 90 minute long, 400 kilometer high orbit, Earth's bright limb is in view above center.
Light from Cygnus A (2015-01-24)

Celebrating astronomy in this International Year of Light, the detailed image reveals spectacular active galaxy Cygnus A in light across the electromagnetic spectrum. Incorporating X-ray data ( blue) from the orbiting Chandra Observatory, Cygnus A is seen to be a prodigious source of high energy x-rays. But it is actually more famous at the low energy end of the electromagnetic spectrum. One of the brightest celestial sources visible to radio telescopes, at 600 million light-years distant Cygnus A is the closest powerful radio galaxy. Radio emission ( red) extends to either side along the same axis for nearly 300,000 light-years powered by jets of relativistic particles emanating from the galaxy's central supermassive black hole. Hot spots likely mark the ends of the jets impacting surrounding cool, dense material. Confined to yellow hues, optical wavelength data of the galaxy from Hubble and the surrounding field in the Digital Sky Survey complete a remarkable multiwavelength view.
A Twisted Solar Eruptive Prominence (2015-01-25)

Ten Earths could easily fit in the "claw" of this seemingly solar monster.  The monster, actually a huge eruptive prominence, is seen moving out from our Sun in this condensed half-hour time-lapse sequence.  This large prominence, though, is significant not only for its size, but its shape.  The twisted figure eight shape indicates that a complex magnetic field threads through the emerging solar particles.  Differential rotation of gas just inside the surface of the Sun might help account for the surface explosion.  The five frame sequence was taken in early 2000 by the Sun-orbiting SOHO satellite.  Although large prominences and energetic Coronal Mass Ejections (CMEs) are relatively rare, they are again occurring more frequently now that we are near the Solar Maximum, a time of peak sunspot and solar activity in the eleven-year solar cycle.
The Milky Way over the Seven Strong Men Rock Formations (2015-01-26)

You may have heard of the Seven Sisters in the sky, but have you heard about the Seven Strong Men on the ground? Located just west of the Ural Mountains, the unusual Manpupuner rock formations are one of the Seven Wonders of Russia. How these ancient 40-meter high pillars formed is yet unknown.  The persistent photographer of this featured image battled rough terrain and uncooperative weather to capture these rugged stone towers in winter at night, being finally successful in February of last year.  Utilizing the camera's time delay feature, the photographer holds a flashlight in the foreground near one of the snow-covered pillars.  High above, millions of stars shine down, while the band of our Milky Way Galaxy crosses diagonally down from the upper left.    Follow APOD on: Facebook,  Google Plus, or Twitter

Image credit: Sergei Makurin
Our Galaxy's Magnetic Field from Planck (2015-01-27)

What does the magnetic field of our Galaxy look like?  It has long been known that a modest magnetic field pervades our Milky Way Galaxy because it is seen to align small dust grains that scatter background light. Only recently, however, has the Sun-orbiting Planck satellite made a high-resolution map of this field. Color coded, the 30-degree wide map confirms, among other things, that the Galaxy's interstellar magnetism is strongest in the central disk. The revolution of charged gas around the Galactic center creates this magnetism, and it is hypothesized that viewed from the top, the Milky Way's magnetic field would appear as a spiral swirling out from the center. What caused many of the details in this and similar Planck maps -- and how magnetism in general affected our Galaxy's evolution -- will likely remain topics of research for years to come.

Image credit: ESA/Planck;
 Acknowledgement: 
M.-A. Miville-Desch�nes, CNRS � 
IAS, 
U. Paris-XI
Comet Lovejoy in a Winter Sky (2015-01-28)

Which of these night sky icons can you find in this beautiful and deep exposure of the northern winter sky? Skylights include the stars in Orion's belt, the Orion Nebula, the Pleiades star cluster, the bright stars Betelgeuse and Rigel, the California Nebula, Barnard's Loop, and  Comet Lovejoy. The belt stars of Orion are nearly vertical in the central line between the horizon and the image center, with the lowest belt star obscured by the red glowing Flame Nebula. To the belt's left is the red arc of Barnard's Loop followed by the bright orange star Betelgeuse, while to the belt's right is the colorful Orion Nebula followed by the bright blue star Rigel. The blue cluster of bright stars near the top center is the Pleiades, and the red nebula to its left is the California nebula.  The bright orange dot above the image center is the star Aldebaran, while the green object with the long tail to its right is Comet C/2014 Q2 (Lovejoy). The featured image was taken about two weeks ago near Palau village in Spain.
Close Encounter with M44 (2015-01-29)

On Monday, January 26, well-tracked asteroid 2004 BL86 made its closest approach, a mere 1.2 million kilometers from our fair planet. That's about 3.1 times the Earth-Moon distance or 4 light-seconds away. Moving quickly through Earth's night sky, it left this streak in a 40 minute long exposure on January 27 made from Piemonte, Italy. The remarkably pretty telescopic field of view includes M44, also known as the Beehive or Praesepe star cluster in Cancer. Of course, its close encounter with M44 is only an apparent one, with the cluster nearly along the same line-of-sight to the near-earth asteroid. The actual distance between star cluster and asteroid is around 600 light-years. Still, the close approach to planet Earth allowed detailed radar imaging from NASA's Deep Space Network antenna at Goldstone, California and revealed the asteroid to have its own moon.

Image credit: Carlo Dellarole,
Andrea Demarchi
A Night at Poker Flat (2015-01-30)

Four NASA suborbital sounding rockets leapt into the night on January 26, from the University of Alaska's Poker Flat Research Range. This time lapse composite image follows all four launches of the small, multi-stage rockets to explore winter's mesmerizing, aurora-filled skies. During the exposures, stars trailed around the North Celestial Pole, high above the horizon at the site 30 miles north of Fairbanks, Alaska. Lidar, beams of pulsed green lasers, also left traces through the scene. Operating successfully, the payloads lofted were two Mesosphere-Lower Thermosphere Turbulence Experiments (M-TeX) and two Mesospheric Inversion-layer Stratified Turbulence (MIST) experiments, creating vapor trails at high altitudes to be tracked by ground-based observations.
Yellow Balls in W33 (2015-01-31)

Infrared wavelengths of 3.6, 8.0, and 24.0 microns observed by the Spitzer Space Telescope are mapped into visible colors red, green, and blue in this striking image. The cosmic cloud of gas and dust is W33, a massive starforming complex some 13,000 light-years distant, near the plane of our Milky Way Galaxy. So what are all those yellow balls? Citizen scientists of the web-based Milky Way Project found the features they called yellow balls as they scanned many Spitzer images and persistently asked that question of researchers. Now there is an answer. The yellow balls in Spitzer images are identified as an early stage of massive star formation. They appear yellow because they are overlapping regions of red and green, the assigned colors that correspond to dust and organic molecules known as PAHs at Spitzer wavelengths. Yellow balls represent the stage before newborn massive stars clear out cavities in their surrounding gas and dust and appear as green-rimmed bubbles with red centers in the Spitzer image. Of course, the astronomical crowdsourcing success story is only part of the Zooniverse. The Spitzer image spans 0.5 degrees or about 100 light-years at the estimated distance of W33.
NGC 4676: When Mice Collide (2015-02-01)

These two mighty galaxies are pulling each other apart.  Known as the "Mice" because they have such long tails, each spiral galaxy has likely already passed through the other. The long tails are created by the relative difference between gravitational pulls on the near and far parts of each galaxy.  Because the distances are so large, the cosmic interaction takes place in slow motion -- over hundreds of millions of years.  NGC 4676 lies about 300 million light-years away toward the constellation of Bernice's Hair (Coma Berenices) and are  likely members of the Coma Cluster of Galaxies.  The above picture was taken with the Hubble Space Telescope's Advanced Camera for Surveys in 2002. These galactic mice will probably collide again and again over the next billion years until they coalesce to form a single galaxy.
Titan Seas Reflect Sunlight (2015-02-02)

Why would the surface of Titan light up with a blinding flash? The reason: a sunglint from liquid seas.  Saturn's moon Titan has numerous smooth lakes of methane that, when the angle is right, reflect sunlight as if they were mirrors.  Pictured here in false-color, the robotic Cassini spacecraft orbiting Saturn imaged the cloud-covered Titan last summer in different bands of cloud-piercing infrared light.  This specular reflection was so bright it saturated one of Cassini's infrared cameras. Although the sunglint was annoying -- it was also useful.  The reflecting regions confirm that northern Titan houses a wide and complex array of seas with a geometry that indicates periods of significant evaporation.  During its numerous passes of our Solar System's most mysterious moon, Cassini has revealed Titan to be a world with active weather -- including times when it rains a liquefied version of natural gas.
Jets from Comet Churyumov-Gerasimenko (2015-02-03)

Where do comet tails come from? Although it is common knowledge that comet tails and comas originate from comet nuclei, exactly how that happens is an active topic of research.  One of the best images yet of emerging jets is shown in the featured image, taken last November by the robotic Rosetta spacecraft in orbit around the Comet 67P/Churyumov-Gerasimenko (Comet CG), and released last month.  The overexposed picture shows plumes of gas and dust escaping numerous places from the Comet CG's nucleus as it nears the Sun and heats up.  Although Comet CG is currently further out from the Sun than Mars, its orbit will take it almost as close as the Earth this coming August, at which time its jet activity is expected to increase by a factor of about 100. You've likely seen some debris from comet nuclei before but in another form -- when sand-sized bits end their journey through the Solar System by impacting the atmosphere of Earth as meteors.    Almost Hyperspace: Random APOD Generator
Stars, Sprites, Clouds, Auroras (2015-02-04)

What are those red streaks in the sky? While photographing unexpected auroras over a distant thunderstorm, something extraordinary happened: red sprites.  This brief instance of rarely imaged high-altitude lightning flashed so bright that it was witnessed by several people independently.  Pictured over Minnesota, USA in May 2013, these red sprites likely followed an extremely powerful low-altitude conventional lightning bolt.  Captured in the featured frame are a house and electrical pole in the foreground, thick clouds in the lower atmosphere, a lightning storm on the horizon, distant red sprites and green aurora in the upper atmosphere, and distant stars from our local neighborhood of the Milky Way Galaxy.  The spectacular image is thought to be only the second known case of sprites and auroras photographed together, and possibly the first in true color.    Follow APOD on: Facebook,  Google Plus, or Twitter

Image credit: Mike Hollingshead 
(Extreme Instability)
M104: The Sombrero Galaxy (2015-02-05)

The striking spiral galaxy M104 is famous for its nearly edge-on profile featuring a broad ring of obscuring dust lanes. Seen in silhouette against an extensive bulge of stars, the swath of cosmic dust lends a broad brimmed hat-like appearance to the galaxy suggesting the more popular moniker, The Sombrero Galaxy. Hubble Space Telescope and ground-based Subaru data have been reprocessed with amateur color image data to create this sharp view of the well-known galaxy. The processing results in a natural color appearance and preserves details often lost in overwhelming glare of M104's bright central bulge when viewed with smaller ground-based instruments. Also known as NGC 4594, the Sombrero galaxy can be seen across the spectrum and is thought to host a central supermassive black hole. About 50,000 light-years across and 28 million light-years away, M104 is one of the largest galaxies at the southern edge of the Virgo Galaxy Cluster.
Jupiter Triple-Moon Conjunction (2015-02-06)

Our solar system's ruling giant planet Jupiter and 3 of its 4 large Galilean moons are captured in this single Hubble snapshot from January 24. Crossing in front of Jupiter's banded cloud tops Europa, Callisto, and Io are framed from lower left to upper right in a rare triple-moon conjunction. Distinguishable by colors alone icy Europa is almost white, Callisto's ancient cratered surface looks dark brown, and volcanic Io appears yellowish. The transiting moons and moon shadows can be identified by sliding your cursor over the image, or following this link. Remarkably, two small, inner Jovian moons, Amalthea and Thebe, along with their shadows, can also be found in the sharp Hubble view. The Galilean moons have diameters of 3,000 to 5,000 kilometers or so, comparable in size to Earth's moon. But odd-shaped Amalthea and Thebe are only about 260 and 100 kilometers across respectively.
An Aurora of Marbles (2015-02-07)

It looks like a fine collection of aggies. But this grid of embedded swirls and streaks actually follows the dramatic development of planet Earth's auroral substorms. The sequence of over 600 horizon-to-horizon fisheye images was taken over a 2 hour period near the artic circle in March of 2012 from Lapland, northern Sweden. It begins at upper left in evening twilight and ends at lower right, covering two activity peaks with bright coronae forming overhead. While exploring space between Earth and Moon, NASA's fleet of THEMIS spacecraft discovered that these explosions of auroral activity are driven by sudden releases of energy in the Earth's magnetosphere. Even if you're not playing for keepsies, you can follow this link to check out the sequence in a full timelapse video (vimeo).

Image credit: Babak Tafreshi
Carina Nebula Dust Pillar (2015-02-08)

This cosmic pillar of gas and dust is nearly two light-years wide. The structure lies within one of our galaxy's largest star forming regions, the Carina Nebula, shining in southern skies at a distance of about 7,500 light-years. The pillar's convoluted outlines are shaped by the winds and radiation of Carina's young, hot, massive stars. But the interior of the cosmic pillar itself is home to stars in the process of formation. In fact, a penetrating  infrared view shows the pillar is dominated by two, narrow, energetic jets blasting outward from a still hidden infant star. The above featured visible light image was made in 2009 using the Hubble Space Telescope's Wide Field Camera 3.
Layered Rocks near Mount Sharp on Mars (2015-02-09)

What caused these Martian rocks to be layered? The leading hypothesis is an ancient Martian lake that kept evaporating and refilling over 10 million years -- but has now remained dry and empty of water for billions of years.  The featured image, taken last November by the robotic Curiosity rover, shows one-meter wide Whale Rock which is part of the Pahrump Hills outcrop at the base of Mount Sharp. Also evident in the image is cross-bedding -- rock with angled layers -- which were likely facilitated by waves of sand.  Curiosity continues to find many layered rocks like this as it continues to roll around and up 5.5-km high Mount Sharp.
An Extremely Long Filament on the Sun (2015-02-10)

Yesterday, the Sun exhibited one of the longest filaments ever recorded.  It may still be there today. Visible as the dark streak just below the center in the featured image, the enormous filament extended across the face of the Sun a distance even longer than the Sun's radius -- over 700,000 kilometers. A filament is actually hot gas held aloft by the Sun's magnetic field, so that viewed from the side it would appear as a raised prominence.  The featured image shows the filament in light emitted by hydrogen and therefore highlights the Sun's chromosphere.  Sun-following telescopes including NASA's Solar Dynamics Observatory (SDO) are tracking this unusual feature, with SDO yesterday recording a spiraling magnetic field engulfing it.  Since filaments typically last only from hours to days, parts of this one may collapse or erupt at any time, either returning hot plasma back to the Sun or expelling it into the Solar System.  Is the filament still there?  You can check by clicking on SDO's current solar image.   Follow APOD on: Facebook,  Google Plus, or Twitter

Image credit: Oliver Hardy
M100: A Grand Design Spiral Galaxy (2015-02-11)

Majestic on a truly cosmic scale, M100 is appropriately known as a grand design spiral galaxy.  It is a large galaxy of over 100 billion stars with well-defined spiral arms that is similar to our own Milky Way Galaxy.  One of the brightest members of the Virgo Cluster of galaxies, M100 (alias NGC 4321) is 56 million light-years distant toward the constellation of Berenice's Hair (Coma Berenices).  This Hubble Space Telescope image of M100 was made in 2009 and reveals bright blue star clusters and intricate winding dust lanes which are hallmarks of this class of galaxies.  Studies of variable stars in M100 have played an important role in determining the size and age of the Universe. If you know exactly where to look, you can find a small spot that is a light echo from a bright supernova that was recorded a few years before the image was taken.
Exploring the Antennae (2015-02-12)

Some 60 million light-years away in the southerly constellation Corvus, two large galaxies are colliding. The stars in the two galaxies, cataloged as NGC 4038 and NGC 4039, very rarely collide in the course of the ponderous cataclysm, lasting hundreds of millions of years. But their large clouds of molecular gas and dust often do, triggering furious episodes of star formation near the center of the cosmic wreckage. Spanning about 500 thousand light-years, this stunning composited view also reveals new star clusters and matter flung far from the scene of the accident by gravitational tidal forces. The remarkable collaborative image is a mosaic constructed using data from small and large ground-based telescopes to bring out large-scale and faint tidal streams, composited with the bright cores imaged in extreme detail by the Hubble Space Telescope. Of course, the suggestive visual appearance of the extended arcing structures gives the galaxy pair its popular name - The Antennae.