juliensimon/nasa-apod huggingface dataset:
Aurora on Ice (2015-02-13)

Not from a snowglobe, this expansive fisheye view of ice and sky was captured on February 1, from Jökulsárlón Beach, southeast Iceland, planet Earth. Chunks of glacial ice on the black sand beach glisten in the light of a nearly full moon surrounded by a shining halo. The 22 degree lunar halo itself is created by ice crystals in high, thin clouds refracting the moonlight. Despite the bright moonlight, curtains of aurora still dance through the surreal scene. In early February, their activity was triggered by Earth's restless magnetosphere and the energetic wind from a coronal hole near the Sun's south pole. Bright Jupiter, also near opposition, is visible at the left, beyond the icy lunar halo.

Image credit: Stéphane
Vetter
Solar System Portrait (2015-02-14)

On another Valentine's Day 25 years ago, cruising four billion miles from the Sun, the Voyager 1 spacecraft looked back one last time to make this first ever Solar System family portrait. The complete portrait is a 60 frame mosaic made from a vantage point 32 degrees above the ecliptic plane. In it, Voyager's wide angle camera frames sweep through the inner Solar System at the left, linking up with gas giant Neptune, the Solar System's outermost planet, at the far right. Positions for Venus, Earth, Jupiter, Saturn, Uranus, and Neptune are indicated by letters, while the Sun is the bright spot near the center of the circle of frames. The inset frames for each of the planets are from Voyager's narrow field camera. Unseen in the portrait are Mercury, too close to the Sun to be detected, and Mars, unfortunately hidden by sunlight scattered in the camera's optical system. Closer to the Sun than Neptune at the time, small, faint Pluto's position was not covered.
Two Hours Before Neptune (2015-02-15)

Two hours before closest approach to Neptune in 1989, the Voyager 2 robot spacecraft snapped this picture. Clearly visible for the first time were long light-colored cirrus-type clouds floating high in Neptune's atmosphere. Shadows of these clouds can even be seen on lower cloud decks.  Most of Neptune's atmosphere is made of hydrogen and helium, which is invisible.  Neptune's blue color therefore comes from smaller amounts of atmospheric methane, which preferentially absorbs red light.  Neptune has the fastest winds in the Solar System, with gusts reaching 2000 kilometers per hour.  Speculation holds that diamonds may be created in the dense hot conditions that exist under the cloud tops of Uranus and Neptune. Twenty-six years later, NASA's New Horizons is poised to be the first spacecraft  to zoom past Pluto this July.   Almost Hyperspace: Random APOD Generator
M106: A Spiral Galaxy with a Strange Center (2015-02-16)

What's happening at the center of spiral galaxy M106? A swirling disk of stars and gas, M106's appearance is dominated by blue spiral arms and red  dust lanes near the nucleus, as shown in the featured image.  The core of M106 glows brightly in radio waves and X-rays where twin jets have been found running the length of the galaxy.  An unusual central glow makes M106 one of the closest examples of the Seyfert class of galaxies, where vast amounts of glowing gas are thought to be falling into a central massive black hole.  M106, also designated NGC 4258, is a relatively close 23.5 million light years away, spans 60 thousand light years across, and can be seen with a small telescope towards the constellation of the Hunting Dogs (Canes Venatici).    Astrophysicists: Browse 1,000+ codes in the Astrophysics Source Code Library
Fibrils Flower on the Sun (2015-02-17)

When does the Sun look like a flower?  In a specific color of red light emitted by hydrogen, as featured here, some regions of the solar chromosphere may resemble a rose.  The color-inverted image was taken in 2014 October and shows active solar region 2177.  The petals dominating the frame are actually magnetically confined tubes of hot plasma called fibrils, some of which extend longer than the diameter of the Earth.  In the central region many of these fibrils are seen end-on, while the surrounding regions are typically populated with curved fibrils.  When seen over the Sun's edge, these huge plasma tubes are called spicules, and when they occur in passive regions they are termed mottles.  Sunspot region 2177 survived for several more days before the complex and tumultuous magnetic field poking through the Sun's surface evolved yet again.    Follow APOD on: Facebook,  Google Plus, or Twitter

Image credit: Big Bear Solar Obs., 
NJIT, 
Alan Friedman
(Averted Imagination)
Dark Craters and Bright Spots Revealed on Asteroid Ceres (2015-02-18)

What are those bright spots on asteroid Ceres? As the robotic spacecraft Dawn approaches the largest asteroid in the asteroid belt, the puzzle only deepens. Sharper new images taken last week and released yesterday indicate, as expected, that most of the surface of dwarf planet Ceres is dark and heavily cratered like our Moon and the planet Mercury. The new images do not clearly indicate, however, the nature of comparatively bright spots -- although more of them are seen to exist.  The enigmatic spots were first noticed on Texas-sized Ceres a few weeks ago during Dawn's approach. The intriguing mystery might well be solved quickly as Dawn continues to advance toward Ceres, being on schedule to enter orbit on March 6.    Poll: What do you think the light spots on Ceres are?
Palomar 12 (2015-02-19)

Palomar 12 was not born here. The stars of the globular cluster, first identified in the Palomar Sky Survey, are younger than those in other globular star clusters that roam the halo of our Milky Way Galaxy. Palomar 12's position in our galaxy and measured motion suggest its home was once the Sagittarius Dwarf Elliptical Galaxy, a small satellite of the Milky Way. Disrupted by gravitational tides during close encounters the satellite galaxy has lost its stars to the larger Milky Way. Now part of the Milky Way's halo, the tidal capture of Palomar 12 likely took place some 1.7 billion years ago. Seen behind spiky foreground stars in the sharp Hubble image, Palomar 12 spans nearly 60 light-years. Still much closer than the faint, fuzzy, background galaxies scattered throughout the field of view, it lies about 60,000 light-years away, toward the constellation Capricornus.
An Evening Sky Conjunction (2015-02-20)

ght years ago, an evening sky held this lovely pairing of a young crescent Moon and brilliant Venus. Seen near the western horizon, the close conjunction and its wintry reflection were captured from Bolu, Turkey, planet Earth on February 19, 2007. In the 8 Earth years since this photograph was taken Venus has orbited the Sun almost exactly 13 times, so the Sun and Venus have now returned to the same the configuration in Earth's sky. And since every 8 years the Moon also nearly repeats its phases for a given time of year, a very similar crescent Moon-Venus conjunction will again appear in planet Earth's evening skies tonight. But the February 20, 2015 version of the conjunction will also include planet Mars. Much fainter Mars will wander even closer to Venus by the evening of February 21.

Image credit: Tunç Tezel
45 Days in the Sun (2015-02-21)

From January 11 to February 25 2013, a pinhole camera sat in a field near Budapest, Hungary, planet Earth to create this intriguing solargraph. And for 45 days, an old Antonov An-2 biplane stood still while the Sun rose and set. The camera's continuous exposure began about 20 days after the northern hemispere's winter solstice, so each day the Sun's trail arcs steadily higher through the sky. These days in the Sun were recorded on a piece of black and white photosensitive paper tucked in to the simple plastic film container. The long exposure produced a visible color image on the paper that was then digitally scanned. Of course, cloudy days left gaps in the solargraph's Sun trails.

Image credit: Csaba
Kovács
The Dark River to Antares (2015-02-22)

Connecting the Pipe Nebula to the colorful region near bright star Antares is a dark cloud dubbed the Dark River,  flowing from the picture's left edge. Murky looking, the Dark River's appearance is caused by dust obscuring background starlight, although the dark nebula contains mostly hydrogen and molecular gas.  Surrounded by dust, Antares, a red supergiant star, creates an unusual bright yellowish reflection nebula. Above it, bright blue double star Rho Ophiuchi is embedded in one of the more typical bluish reflection nebulae, while red emission nebulae are also scattered around the region. Globular star cluster M4 is just seen above and right of Antares, though it lies far behind the colorful clouds, at a distance of some 7,000 light-years. The Dark River itself is about 500 light years away.  The colorful skyscape is a mosaic of telescopic images spanning nearly 10 degrees (20 Full Moons) across the sky in the constellation of the Scorpion (Scorpius).    Follow APOD on: Facebook,  Google Plus, or Twitter

Image credit: Jason Jennings
The Milky Way Over the Arizona Toadstools (2015-02-23)

Which is older -- the rocks you see on the ground or the light you see from the sky? Usually it�s the rocks that are older, with their origin sediments deposited well before light left any of the stars or nebulas you see in the sky. However, if you can see, through a telescope, a distant galaxy far across the universe -- further than Andromeda or spiral galaxy NGC 7331 (inset) -- then you are seeing light even more ancient. Featured here, the central disk of our Milky Way Galaxy arches over Toadstool hoodoos rock formations in northern Arizona, USA. The unusual Toadstool rock caps are relatively hard sandstone that wind has eroded more slowly than the softer sandstone underneath.  The green bands are airglow, light emitted by the stimulated air in Earth's atmosphere. On the lower right is a time-lapse camera set up to capture the sky rotating behind the picturesque foreground scene.

Image credit: David Lane & 
R. Gendler (3 insets)
Unusual Plumes Above Mars (2015-02-24)

What is creating unusual plumes on Mars? No one is sure.  Noted and confirmed by a global contingent of amateur astronomers on photos of the red planet in March 2012, possibly similar plumes have now been found on archived images as far back as 1997.  Since the plumes reach 200 kilometers up, they seem too high to be related to wind-blown surface dust.  Since one plume lasted for eleven days, it seemed too long lasting to be related to aurora. Amateur astronomers will surely continue to monitor the terminator and edge regions of Mars for new high plumes, and the armada of satellites orbiting Mars may be called upon to verify and study any newly reported plume that become visible. The featured 35-minute time-lapse animation was taken on 2012 March 20 by the plume's discoverer -- an attorney from Pennsylvania, USA.    Poll: What do you think these unusual Martian plumes are?

Image credit: W. Jaeschke
The Rosette Nebula in Hydrogen and Oxygen (2015-02-25)

The Rosette Nebula is not the only cosmic cloud of gas and dust to evoke the imagery of flowers -- but it is the most famous.  At the edge of a large molecular cloud in Monoceros, some 5,000 light years away, the petals of this rose are actually a stellar nursery whose lovely, symmetric shape is sculpted by the winds and radiation from its central cluster of hot young stars. The stars in the energetic cluster, cataloged as NGC 2244, are only a few million years old, while the central cavity in the Rosette Nebula, cataloged as NGC 2237, is about 50 light-years in diameter. The nebula can be seen firsthand with a small telescope toward the constellation of the Unicorn (Monoceros).   Follow APOD on: Facebook,  Google Plus, or Twitter

Image credit: Arno Rottal
(Far-Light-Photography)
Love and War by Moonlight (2015-02-26)

Venus, named for the Roman goddess of love, and Mars, the war god's namesake, came together by moonlight in this lovely skyview, recorded on February 20 from Charleston, South Carolina, USA, planet Earth. Made in twilight with a digital camera, the three second time exposure also records earthshine illuminating the otherwise dark surface of the young crescent Moon. Of course, the Moon has moved on from this much anticipated triple conjunction. Venus still shines in the west though as the evening star, third brightest object in Earth's sky, after the Sun and the Moon itself. Seen here within almost a Moon's width of Venus, much fainter Mars approached even closer on the following evening. But Mars has since been moving slowly away from brilliant Venus, though Mars is still visible too in the western twilight.

Image credit: Kevin Bourque
Long Lovejoy and Little Dumbbell (2015-02-27)

Buffeted by the solar wind, Comet Lovejoy's crooked ion tail stretches over 3 degrees across this telescopic field of view, recorded on February 20. The starry background includes awesome bluish star Phi Persei below, and pretty planetary nebula M76 just above Lovejoy's long tail. Also known as the Little Dumbbell Nebula, after its brighter cousin M27 the Dumbbell Nebula, M76 is only a Full Moon's width away from the comet's greenish coma. Still shining in northern hemisphere skies, this Comet Lovejoy (C/2014 Q2) is outbound from the inner solar system some 10 light-minutes or 190 million kilometers from Earth. But the Little Dumbbell actually lies over 3 thousand light-years away. Now sweeping steadily north toward the constellation Cassiopeia Comet Lovejoy is fading more slowly than predicted and is still a good target for small telescopes.

Image credit: CARA Project
Moon-Venus-Mars Skyline (2015-02-28)

Taken on February 20, five different exposures made in rapid succession were used to created this tantalizing telephoto image. In combination, they reveal a wide range of brightness visible to the eye on that frigid evening, from the urban glow of the Quebec City skyline to the triple conjunction of Moon, Venus and Mars. Shortly after sunset the young Moon shows off its bright crescent next to brilliant Venus. Fainter Mars is near the top of the frame. Though details in the Moon's sunlit crescent are washed out, features on the dark, shadowed part of the lunar disk are remarkably clear. Still lacking city lights the lunar night is illuminated solely by earthshine, light reflected from the sunlit side of planet Earth.

Image credit: Jay Ouellet
Inside the Coma Cluster of Galaxies (2015-03-01)

Almost every object in the above photograph is a galaxy.  The Coma Cluster of Galaxies pictured above is one of the densest clusters known - it contains thousands of galaxies.  Each of these galaxies houses billions of stars - just as our own Milky Way Galaxy does.  Although nearby when compared to most other clusters, light from the Coma Cluster still takes hundreds of millions of years to reach us.  In fact, the Coma Cluster is so big it takes light millions of years just to go from one side to the other!  The above mosaic of images of a small portion of Coma was taken in unprecedented detail in 2006 by the Hubble Space Telescope to investigate how galaxies in rich clusters form and evolve.  Most galaxies in Coma and other clusters are ellipticals, although some imaged here are clearly spirals.   The spiral galaxy on the upper left of the above image can also be found as one of the bluer galaxies on the upper left of this wider field image. In the background thousands of unrelated galaxies are visible far across the universe.
Lenticular Cloud, Moon, Mars, Venus (2015-03-02)

It is not every day that such an interesting cloud photobombs your image. The original plan was to photograph a rare angular conjunction of Mars and Venus that occurred a week and a half ago, with the added bonus of a crescent Moon and the International Space Station (ISS) both passing nearby. Unfortunately, on Madeira Island, Portugal, this event was clouded out. During the next day, however, a spectacular lenticular cloud appeared before sunset, so the industrious astrophotographer quickly formulated a new plan.  A close look at the resulting image reveals the Moon visible toward the left of the frame, while underneath, near the bottom, are the famous planets with Venus being the brighter.  It was the unexpected lenticular cloud, though, perhaps looking like some sort of futuristic spaceship, that stole the show.  The setting Sun illuminated the stationary cloud (and everything else) from the bottom, setting up an intricate pattern of shadows, layers, and brightly illuminated regions, all seen evolving in a corresponding video.  Mars and Venus will next appear this close on the sky in late August, but whether any place on Earth will catch them behind such a photogenic cloud is unknown.    Follow APOD on: Facebook,  Google Plus, or Twitter

Image credit: Nuno Serr�o
A Dust Devil on Mars (2015-03-03)

It was late in the northern martian spring when the HiRISE camera onboard the Mars Reconnaissance Orbiter spied this local denizen. Tracking across the flat, dust-covered Amazonis Planitia in 2012, the core of this whirling dust devil is about 140 meters in diameter. Lofting dust into the thin martian atmosphere, its plume reaches about 20 kilometers above the surface. Common to this region of Mars, dust devils occur as the surface is heated by the Sun, generating warm, rising air currents that begin to rotate. Tangential wind speeds of up to 110 kilometers per hour are reported for dust devils in other HiRISE images.   Follow APOD on: Facebook,  Google Plus, or Twitter
Pillars and Jets in the Pelican Nebula (2015-03-04)

What dark structures arise from the Pelican Nebula? Visible as a bird-shaped nebula toward the constellation of a bird (Cygnus, the Swan), the Pelican Nebula is a place dotted with newly formed stars but fouled with dark dust. These smoke-sized dust grains formed in the cool atmospheres of young stars and were dispersed by stellar winds and explosions.  Impressive Herbig-Haro jets are seen emitted by a star on the right that is helping to destroy the light year-long dust pillar that contains it.  The featured image was scientifically-colored to emphasize light emitted by small amounts of ionized nitrogen, oxygen, and sulfur in the nebula made predominantly of hydrogen and helium.  The Pelican Nebula (IC 5067 and IC 5070) is about 2,000 light-years away and can be found with a small telescope to the northeast of the bright star Deneb.

Image credit: Larry Van Vleet
(LVVASTRO)
Enhanced Color Caloris (2015-03-05)

The sprawling Caloris basin on Mercury is one of the solar system's largest impact basins, created during the early history of the solar system by the impact of a large asteroid-sized body. The multi-featured, fractured basin spans about 1,500 kilometers in this enhanced color mosaic based on image data from the Mercury-orbiting MESSENGER spacecraft. Mercury's youngest large impact basin, Caloris was subsequently filled in by lavas that appear orange in the mosaic. Craters made after the flooding have excavated material from beneath the surface lavas. Seen as contrasting blue hues, they likely offer a glimpse of the original basin floor material. Analysis of these craters suggests the thickness of the covering volcanic lava to be 2.5-3.5 kilometers. Orange splotches around the basin's perimeter are thought to be volcanic vents.
Cometary Globule CG4 (2015-03-06)

The faint and somehow menacing cometary globule CG4 reaches through the center of this deep southern skyscape. About 1,300 light-years from Earth toward the constellation Puppis, its head is about 1.5 light-years in diameter and its tail about 8 light-years long. That's far larger than the Solar System's comets that it seems to resemble. In fact, the dusty cloud contains enough material to form several Sun-like stars and likely has ongoing star formation within. How its distinctive form came about is still debated, but its long tail trails away from the Vela Supernova remnant near the center of the Gum Nebula, while its head could represent the rupture of an originally more spherical cloud. Still, the edge-on spiral galaxy also near picture center is not actually being threatened by CG4. The galaxy lies in the distant background more than 100 million light-years away.

Image credit: CEDIC Team
NGC 602 in the Flying Lizard Nebula (2015-03-07)

Near the outskirts of the Small Magellanic Cloud, a satellite galaxy some 200 thousand light-years distant, lies 5 million year young star cluster NGC 602. Surrounded by natal gas and dust, NGC 602 is just below center in this telescopic field of view with the angular size of the Full Moon on the sky. The cluster itself is about 200 light-years in diameter. Glowing interior ridges and swept back shapes strongly suggest that energetic radiation and shock waves from NGC 602's massive young stars have eroded the dusty material and triggered a progression of star formation moving away from the cluster's center. Of course, the more extended wings of emission in the region suggest a popular name for the complex cosmic environment, The Flying Lizard Nebula.

Image credit: Don Goldman
Stars at the Galactic Center (2015-03-08)

The center of our Milky Way Galaxy is hidden from the prying eyes of optical telescopes by clouds of obscuring dust and gas. But in this stunning vista, the Spitzer Space Telescope's infrared cameras, penetrate much of the dust revealing the stars of the crowded galactic center region. A mosaic of many smaller snapshots, the detailed, false-color image shows older, cool stars in bluish hues. Reddish glowing dust clouds are associated with young, hot stars in stellar nurseries. The very center of the Milky Way was only recently found capable of forming newborn stars. The galactic center lies some 26,000 light-years away, toward the constellation Sagittarius. At that distance, this picture spans about 900 light-years.
Galaxy and Cluster Create Four Images of Distant Supernova (2015-03-09)

What are the unusual spots surrounding that galaxy? They are all images of the same supernova. For the first time, a single supernova explosion has been seen split into multiple images by the gravitational lens deflections of intervening masses. In this case the masses are a large galaxy and its home galaxy cluster. The featured image was captured last November by the Earth-orbiting Hubble Space Telescope.  The yellow-hued quadruply-imaged Supernova Refsdal occurred in the early universe far behind the cluster. Measuring the locations and time-delays between the supernova images should allow astrophysicists to recover the amount of dark matter in the galaxy and cluster. With patience and luck, a fifth image of the supernova will also be recovered nearby in the next few years.   Astrophysicists: Browse 1,000+ codes in the Astrophysics Source Code Library
Aurora over Icelandic Glacier (2015-03-10)

Several key conditions came together to create this award-winning shot. These included a dark night, few clouds, an epic auroral display, and a body of water that was both calm enough and unfrozen enough to show reflected stars. The featured skyscape of activity and serenity appeared over Iceland's Vatnaj�kull Glacier a year ago January, with the J�kuls�rl�n Iceberg Lagoon captured in the foreground. Aurora filled skies continue to be common near Earth's poles as our Sun, near Solar Maximum, continues to expel energetic clouds of plasma into the Solar System.    Follow APOD on: Facebook,  Google Plus, or Twitter

Image credit: James Boardman Woodend 
(Images Inspired by Nature)