omnianasa/nasa-apod-metadata huggingface dataset:
Orion above Easter Island (2017-09-18)
Why were the statues on Easter Island built? No one is sure.  What is sure is that over 800 large stone statues exist there.  The Easter Island statues, stand, on the average, over twice as tall as a person and have over 200 times as much mass.  Few specifics are known about the history or meaning of the unusual rock sculptures, but many believe that they were created about 700 years ago in the images of local leaders of a lost civilization.  Featured here, one of the ancient Moai sculptures was imaged in 2016 before the constellation of Orion, including the famous line of three belt stars and brilliant stars Betelgeuse (far left in red) and Rigel (upper center). The stone giant appears, however, to be inspecting the brightest star in the night sky (far right): Sirius.    Follow APOD on: Facebook,  Google Plus,  Instagram, or Twitter
Veil Nebula: Wisps of an Exploded Star (2017-09-19)
Wisps like this are all that remain visible of a Milky Way star.  About 7,000 years ago that star exploded in a supernova leaving the Veil Nebula. At the time, the expanding cloud was likely as bright as a crescent Moon, remaining visible for weeks to people living at the dawn of recorded history.  Today, the resulting supernova remnant, also known as the Cygnus Loop, has faded and is now visible only through a small telescope directed toward the constellation of the Swan (Cygnus). The remaining Veil Nebula is physically huge, however, and even though it lies about 1,400 light-years distant, it covers over five times the size of the full Moon.  The featured picture is a Hubble Space Telescope mosaic of six images together covering a span of only about two light years, a small part of the expansive supernova remnant. In images of the complete Veil Nebula, even studious readers might not be able to identify the featured filaments.
The Big Corona (2017-09-20)
Most photographs don't adequately portray the magnificence of the Sun's corona. Seeing the corona first-hand during a total solar eclipse is unparalleled.  The human eye can adapt to see coronal features and extent that average cameras usually cannot. Welcome, however, to the digital age.  The featured picture is a combination of forty exposures from one thousandth of a second to two seconds that, together, were digitally combined and processed to highlight faint features of the total solar eclipse that occurred in August of 2017.  Clearly visible are intricate layers and glowing caustics of an ever changing mixture of hot gas and magnetic fields in the Sun's corona.  Looping prominences appear bright pink just past the Sun's limb.  Faint details on the night side of the New Moon can even be made out, illuminated by sunlight reflected from the dayside of the Full Earth.
A September Morning Sky (2017-09-21)
The Moon, three planets, and a bright star gathered near the ecliptic plane in the September 18 morning sky over Veszprem Castle, Hungary. In this twilight skyscape, Mercury and Mars still shine close to the eastern horizon, soon to disappear in the glare of the Sun. Regulus, alpha star of the constellation Leo, is the bright point next to a waning crescent Moon, with brilliant Venus near the top of the frame. The beautiful morning conjunction of Moon, planets, and bright star could generally be followed by early morning risers all around planet Earth. But remarkably, the Moon also occulted, or passed directly in front of, Regulus and each of the three planets within 24 hours, all on September 18 UT. Visible from different locations, timing and watching the lunar occultations was much more difficult though, and mostly required viewing in daytime skies.
Solar Eclipse Solargraph (2017-09-22)
Today is the September equinox. Heading south, the Sun's path through the sky will cross the celestial equator at 20:02 UT. Of course the equinox date results in (mostly) equal night and day all over planet Earth. But on August 21 the Sun's path through the sky found a little extra-night for some. Made with a drink can pinhole camera and light-sensitive paper, this creative solargraph follows the Sun's path on that date. An all-day exposure, it traces the Sun's arc still rising high in northern skies, aligned with a panoramic snapshot of the local landscape at the bottom. The gap in the arc represents the duration of the partial and total phases of the solar eclipse in clear skies over Lowman, Idaho, USA. There, the extra-night (totality) lasted for about 2 minutes. The broad gap in the Sun's arc also covers the loss of sunlight during the more extended partial eclipse phases.
A Conjunction of Comets (2017-09-23)
A conjunction of comets is captured in this pretty star field from the morning of September 17. Discovered in July by a robotic sky survey searching for supernovae, comet C/2017 O1 ASASSN is at the lower left. The visible greenish glow of its coma is produced by the fluorescence of diatomic carbon molecules in sunlight. Nearing its closest approach to the Sun, the binocular comet was only about 7.2 light-minutes from Earth. In the same telescopic field of view is the long-tailed, outbound comet C/2015 ER61 PanSTARRS at the upper right, almost 14 light-minutes away. Many light-years distant, the starry background includes faint, dusty nebulae of the Milky Way.  The well-known Pleiades star cluster lies just off the top right of the frame.
How to Identify that Light in the Sky (2017-09-24)
What is that light in the sky? Perhaps one of humanity's more common questions, an answer may result from a few quick observations.  For example -- is it moving or blinking? If so, and if you live near a city, the answer is typically an airplane, since planes are so numerous and so few stars and satellites are bright enough to be seen over the din of artificial city lights. If not, and if you live far from a city, that bright light is likely a planet such as Venus or Mars -- the former of which is constrained to appear near the horizon just before dawn or after dusk.  Sometimes the low apparent motion of a distant airplane near the horizon makes it hard to tell from a bright planet, but even this can usually be discerned by the plane's motion over a few minutes. Still unsure?   The featured chart gives a sometimes-humorous but mostly-accurate assessment.  Dedicated sky enthusiasts will likely note -- and are encouraged to provide -- polite corrections.   Chart translations: Spanish, Italian, Polish, Tamil, Kannada, Latvian, and Norwegian
Massive Shell-Expelling Star G79.29+0.46 (2017-09-25)
Stars this volatile are quite rare.  Captured in the midst of dust clouds and visible to the right and above center is massive G79.29+0.46, one of less than 100 luminous blue variable stars (LBVs) currently known in our Galaxy.  LBVs expel shells of gas and may lose even the mass of Jupiter over 100 years.  The star, itself bright and blue, is shrouded in dust and so not seen in visible light. The dying star appears green and surrounded by red shells, though, in this mapped-color infrared picture combining images from NASA's Spitzer Space Observatory and NASA's Wide-Field Infrared Survey Explorer.  G79.29+0.46 is located in the star-forming Cygnus X region of our Galaxy. Why G79.29+0.46 is so volatile, how long it will remain in the LBV phase, and when it will explode in a supernova is not known.    Free Download: The 2018 APOD Calendar
Cassini's Last Ring Portrait at Saturn (2017-09-26)
How should Cassini say farewell to Saturn?  Three days before plunging into Saturn's sunny side, the robotic Cassini spacecraft swooped far behind Saturn's night side with cameras blazing. Thirty-six of these images have been merged -- by an alert and adept citizen scientist -- into a last full-ring portrait of Cassini's home planet for the past 13 years. The Sun is just above the frame, causing Saturn to cast a dark shadow onto its enormous rings. This shadow position cannot be imaged from Earth and will not be visible again until another Earth-launched spaceship visits the ringed giant.  Data and images from Cassini's mission-ending dive into Saturn's atmosphere on September 15 continue to be analyzed.   Almost Hyperspace: Random APOD Generator
Layers of a Total Solar Eclipse (2017-09-27)
Neither rain, nor snow, nor dark of night can keep a space-based spacecraft from watching the Sun. In fact, from its vantage point 1.5 million kilometers sunward of planet Earth, NASA's SOlar Heliospheric Observatory (SOHO) can always monitor the Sun's outer atmosphere, or corona. But only during a total solar eclipse can Earth-based observers also see the lovely coronal streamers and structures - when the Moon briefly blocks the overwhelmingly bright solar surface. Then, it becomes possible to follow detailed coronal activity all the way down to the Sun's surface.  In the outside layer of this composite image, SOHO's uninterrupted view of the solar corona during last month's eclipse is shown in orange hues. The middle, donut-shaped region is the corona as recorded by the Williams College Eclipse Expedition to Salem, Oregon.  Simultaneously, the inner view is from NASA's Earth-orbiting Solar Dynamics Observatory, which, being outside of totality, was able to image the face of the Sun in extreme ultraviolet light, shown in gold.
LIGO-Virgo GW170814 Skymap (2017-09-28)
From around planet Earth three gravitational wave detectors have now reported a joint detection of ripples in spacetime, the fourth announced detection of a binary black hole merger in the distant Universe. The event was recorded on 2017 August 14, and so christened GW170814, by the LIGO observatory sites in Hanford, Washington and Livingston, Louisiana, and the more recently operational Virgo Observatory near Pisa, Italy. The signal was emitted in the final moments of the coalescence of two black holes of 31 and 25 solar masses located about 1.8 billion light-years away. But comparing the timing of the gravitational wave detections at all three sites allowed astronomers to vastly improve the location of the signal's origin on the sky. Just above the Magellanic clouds and generally toward the constellation Eridanus, the only sky region consistent with signals in all three detectors is indicated by the yellow contour line in this all-sky map. The all-sky projection includes the arc of our Milky Way Galaxy. An improved three-detector location of the gravitational wave source allowed rapid follow-up observations by other, more conventional, electromagnetic wave observatories that can search for potentially related signals. The addition of the Virgo detector also allowed the gravitational wave polarization to be measured, a property that further confirms predictions of Einstein's general relativity.
Puppis A Supernova Remnant (2017-09-29)
Driven by the explosion of a massive star, supernova remnant Puppis A is blasting into the surrounding interstellar medium about 7,000 light-years away. At that distance, this colorful telescopic field based on broadband and narrowband optical image data is about 60 light-years across. As the supernova remnant (upper right) expands into its clumpy, non-uniform surroundings, shocked filaments of oxygen atoms glow in green-blue hues. Hydrogen and nitrogen are in red. Light from the initial supernova itself, triggered by the collapse of the massive star's core, would have reached Earth about 3,700 years ago. The Puppis A remnant is actually seen through outlying emission from the closer but more ancient Vela supernova remnant, near the crowded plane of our Milky Way galaxy. Still glowing across the electromagnetic spectrum Puppis A remains one of the brightest sources in the X-ray sky.
Portrait of NGC 281 (2017-09-30)
Look through the cosmic cloud cataloged as NGC 281 and you might miss the stars of open cluster IC 1590. Still, formed within the nebula that cluster's young, massive stars ultimately power the pervasive nebular glow. The eye-catching shapes looming in this portrait of NGC 281 are sculpted columns and dense dust globules seen in silhouette, eroded by intense, energetic winds and radiation from the hot cluster stars. If they survive long enough, the dusty structures could also be sites of future star formation. Playfully called the Pacman Nebula because of its overall shape, NGC 281 is about 10,000 light-years away in the constellation Cassiopeia. This sharp composite image was made through narrow-band filters, combining emission from the nebula's hydrogen, sulfur, and oxygen atoms in green, red, and blue hues. It spans over 80 light-years at the estimated distance of NGC 281.
Concept Plane: Supersonic Green Machine (2017-10-01)
What will passenger airplanes be like in the future? To help brainstorm desirable and workable attributes, NASA sponsors design competitions. Shown here is an artist's depiction of a concept plane that was suggested in 2010. This futuristic plane would be expected to achieve supersonic speeds, possibly surpassing the speeds of the supersonic transport planes that ran commercially in the late twentieth century. In terms of noise reduction, the future aircraft has been drawn featuring an inverted V wing stretched over its engines. The structure is intended to reduce the sound from annoying sonic booms. Additionally, future airplanes would aim to have relatively little impact on our environment, including green limits on pollution and fuel consumption. Aircraft utilizing similar design concepts might well become operational by the 2030s.
Two Comets and a Star Cluster (2017-10-02)
Two unusual spots are on the move near the famous Pleiades star cluster. Shifting only a small amount per night, these spots are actually comets in our nearby Solar System that by chance wandered into the field of the light-years distant stars.  On the far left is comet C/2017 O1 ASAS-SN, a multi-kilometer block of evaporating ice sporting a bright coma of surrounding gas dominated by green-glowing carbon.  Comet ASAS-SN1 shows a slight tail to its lower right.  Near the frame center is comet C/2015 ER61 PanSTARRS, also a giant block of evaporating ice, but sporting a rather long tail to its right. On the upper right is the Pleiades, an open cluster dominated by bright blue stars illuminating nearby reflecting dust.  This exposure, taken about two weeks ago, is so deep that the filamentary interstellar dust can be traced across the entire field. The Pleiades is visible to the unaided eye, but it should require binoculars to see the comets.
Ice Ring around Nearby Star Fomalhaut (2017-10-03)
Why is there a large ice ring around Fomalhaut? This interesting star -- easily visible in the night sky -- lies only about 25 light-years away and is known to be orbited by at least one planet, Dagon, as well as several inner dust disks.  More intriguing, perhaps, is an outer ring, first discovered about 20 years ago, that has an unusually sharp inner boundary. The featured recent image by the Atacama Large Millimeter Array (ALMA) shows this outer ring with complete and unprecedented detail -- in pink -- superposed on a Hubble image of the Fomalhaut system in blue.  A leading theory holds that this ring resulted from numerous violent collisions involving icy comets and planetesimals, the component objects of planets, while the ring boundaries are caused by the gravity of yet unseen planets.  If correct, any interior planets in the Fomalhaut system are likely being continually pelted by large meteors and comets -- an onslaught last seen in our own planetary system four billion years ago in an episode called the Late Heavy Bombardment.    Free Download: The 2018 APOD Calendar
The Soul Nebula in Infrared from Herschel (2017-10-04)
Stars are forming in the Soul of the Queen of Aethiopia. More specifically, a large star forming region called the Soul Nebula can be found in the direction of the constellation Cassiopeia, who Greek mythology credits as the vain wife of a King who long ago ruled lands surrounding the upper Nile river. The Soul Nebula houses several open clusters of stars, a large radio source known as W5, and huge evacuated bubbles formed by the winds of young massive stars. Located about 6,500 light years away, the Soul Nebula spans about 100 light years and is usually imaged next to its celestial neighbor the Heart Nebula (IC 1805). The featured image, impressively detailed, was taken in several bands of infrared light by the orbiting Herschel Space Observatory.    Follow APOD on Facebook: In English, Spanish, Portuguese, or Catalan
Pluto's Bladed Terrain (2017-10-05)
Imaged during the New Horizons spacecraft flyby in July 2015, Pluto's bladed terrain is captured in this close-up of the distant world. The bizarre texture belongs to fields of skyscraper-sized, jagged landforms made almost entirely of methane ice, found at extreme altitudes near Pluto's equator. Casting dramatic shadows, the tall, knife-like ridges seem to have been formed by sublimation. By that process, condensed methane ice turns directly to methane gas without passing through a liquid phase during Pluto's warmer geological periods. On planet Earth, sublimation can also produce standing fields of knife-like ice sheets, found along the high plateau of the Andes mountain range. Known as penitentes, those bladed structures are made of water ice and at most a few meters tall.
Global Aurora at Mars (2017-10-06)
A strong solar event last month triggered intense global aurora at Mars. Before (left) and during (right) the solar storm, these projections show the sudden increase in ultraviolet emission from martian aurora, more than 25 times brighter than auroral emission previously detected by the orbiting MAVEN spacecraft. With a sunlit crescent toward the right, data from MAVEN's ultraviolet imaging spectrograph is shown in purple hues on the night side of Mars globes simulated to match the observation dates and times. On Mars, solar storms can result in planet-wide aurora because, unlike Earth, the Red Planet isn't protected by a strong global magnetic field that can funnel energetic charged particles toward the poles. For all those on the planet's surface during the solar storm, dangerous radiation levels were double any previously measured by the Curiosity rover. MAVEN is studying whether Mars lost its atmosphere due to its lack of a global magnetic field.
Eclipsosaurus Rex (2017-10-07)
We live in an era where total solar eclipses are possible because at times the apparent size of the Moon can just cover the disk of the Sun. But the Moon is slowly moving away from planet Earth. Its distance is measured to increase about 1.5 inches (3.8 centimeters) per year due to tidal friction. So there will come a time, about 600 million years from now, when the Moon is far enough away that the lunar disk will be too small to ever completely cover the Sun. Then, at best only annular eclipses, a ring of fire surrounding the silhouetted disk of the too small Moon, will be seen from the surface of our fair planet. Of course the Moon was slightly closer and loomed a little larger 100 million years ago. So during the age of the dinosaurs there were more frequent total eclipses of the Sun. In front of the Tate Geological Museum at Casper College in Wyoming, this dinosaur statue posed with a modern total eclipse, though. An automated camera was placed under him to shoot his portrait during the Great American Eclipse of August 21.
Dark Molecular Cloud Barnard 68 (2017-10-08)
Where did all the stars go?  What used to be considered a hole in the sky is now known to astronomers as a dark molecular cloud.  Here, a high concentration of dust and molecular gas absorb practically all the visible light emitted from background stars.  The eerily dark surroundings help make the interiors of molecular clouds some of the coldest and most isolated places in the universe.  One of the most notable of these dark absorption nebulae is a cloud toward the constellation Ophiuchus known as Barnard 68, pictured here.  That no stars are visible in the center indicates that Barnard 68 is relatively nearby, with measurements placing it about 500 light-years away and half a light-year across.  It is not known exactly how molecular clouds like Barnard 68 form, but it is known that these clouds are themselves likely places for new stars to form. In fact, Barnard 68 itself has been found likely to collapse and form a new star system. It is possible to look right through the cloud in infrared light.
Unusual Mountain Ahuna Mons on Asteroid Ceres (2017-10-09)
What created this unusual mountain? Ahuna Mons is the largest mountain on the largest known asteroid in our Solar System, Ceres, which orbits our Sun in the main asteroid belt between Mars and Jupiter. Ahuna Mons, though, is like nothing that humanity has ever seen before. For one thing, its slopes are garnished not with old craters but young vertical streaks.  One hypothesis holds that Ahuna Mons is an ice volcano that formed shortly after a large impact on the opposite side of the dwarf planet loosened up the terrain through focused seismic waves.  The bright streaks may be high in reflective salt, and therefore similar to other recently surfaced material such as visible in Ceres' famous bright spots.  The featured double-height digital image was constructed from surface maps taken of Ceres last year by the robotic Dawn mission.   Open Science: Browse 1,500+ codes in the Astrophysics Source Code Library
Milky Way and Zodiacal Light over Australian Pinnacles (2017-10-10)
What strange world is this? Earth. In the foreground of the featured image are the Pinnacles, unusual rock spires in Nambung National Park in Western Australia. Made of ancient sea shells (limestone), how these human-sized picturesque spires formed remains a topic of research.  The panorama was taken last month.  A ray of zodiacal light, sunlight reflected by dust grains orbiting between the planets in the Solar System, rises from the horizon near the image center. Arching across the top is the central band of our Milky Way Galaxy. The planets Jupiter and Saturn, as well as several famous stars are also visible in the background night sky.   Free Download: The 2018 APOD Calendar
Star Cluster NGC 362 from Hubble (2017-10-11)
If our Sun were near the center of NGC 362, the night sky would glow like a jewel box of bright stars. Hundreds of stars would glow brighter than Sirius, and in many different colors. Although these stars could become part of breathtaking constellations and intricate folklore, it would be difficult for planetary inhabitants there to see -- and hence understand -- the greater universe beyond.  NGC 362 is one of only about 170 globular clusters of stars that exist in our Milky Way Galaxy. This star cluster is one of the younger globulars, forming likely well after our Galaxy.  NGC 362 can be found with the unaided eye nearly in front of the Small Magellanic Cloud, and angularly close to the second brightest globular cluster known, 47 Tucanae.  The featured image was taken with the Hubble Space Telescope to help better understand how massive stars end up near the center of some globular clusters.
NGC 1365: Majestic Island Universe (2017-10-12)
Barred spiral galaxy NGC 1365 is truly a majestic island universe some 200,000 light-years across. Located a mere 60 million light-years away toward the chemical constellation Fornax, NGC 1365 is a dominant member of the well-studied Fornax galaxy cluster. This impressively sharp color image shows intense star forming regions at the ends of the bar and along the spiral arms, and details of dust lanes cutting across the galaxy's bright core. At the core lies a supermassive black hole. Astronomers think NGC 1365's prominent bar plays a crucial role in the galaxy's evolution, drawing gas and dust into a star-forming maelstrom and ultimately feeding material into the central black hole.