juliensimon/nasa-apod huggingface dataset:
The Veins of Heaven (2025-07-11)

Transfusing sunlight as the sky grew darker, this exceptional display of noctilucent clouds was captured on July 10, reflected in the calm waters of Vallentuna Lake near Stockholm, Sweden. From the edge of space, about 80 kilometers above Earth's surface, the icy clouds themselves still reflect sunlight, even though the Sun is below the horizon as seen from the ground. Usually spotted at high latitudes in summer months, the night shining clouds have made a strong showing so far during the short northern summer nights. Also known as polar mesopheric clouds they are understood to form as water vapor driven into the cold upper atmosphere condenses on the fine dust particles supplied by disintegrating meteors or volcanic ash.

Image credit: Clear Skies
Clouds and the Golden Moon (2025-07-12)

As the Sun set, a bright Full Moon rose on July 10. Its golden light illuminates clouds drifting through southern hemisphere skies in this well-composed telephoto image from Conceição do Coité, Bahia, Brazil. The brightest lunar phase is captured here with both a short and long exposure. The two exposures were combined to reveal details of the lunar surface in bright moonlight and a subtle iridescence along the dramatically backlit cloudscape. Of course, July's Full Moon is a winter moon in the southern hemisphere.  But in the north it's known to some as the Thunder Moon, likely a nod to the sounds of this northern summer month's typically stormy weather.

Image credit: Alexsandro Mota
Planetary Nebula Mz3: The Ant Nebula (2025-07-13)

Why isn't this ant a big sphere?  Planetary nebula Mz3 is being cast off by a star similar to our Sun that is, surely, round.  Why then would the gas that is streaming away create an ant-shaped nebula that is distinctly not round?  Clues might include the high 1000-kilometer per second speed of the expelled gas, the light-year long length of the structure, and the magnetism of the star featured here at the nebula's center.  One possible answer is that Mz3 is hiding a second, dimmer star that orbits close in to the bright star.  A competing hypothesis holds that the central star's own spin and magnetic field are channeling the gas.  Since the central star appears to be so similar to our own Sun, astronomers hope that increased understanding of the history of this giant space ant can provide useful insight into the likely future of our own Sun and Earth.   Explore Your Universe: Random APOD Generator
NGC 2685: The Helix Galaxy (2025-07-14)

What is going on with this galaxy? NGC 2685 is a confirmed polar ring galaxy - a rare type of galaxy with stars, gas and dust orbiting in rings perpendicular to the plane of a flat galactic disk. The bizarre configuration could be caused by the chance capture of material from another galaxy by a disk galaxy, with the captured debris strung out in a rotating ring. Still, observed properties of NGC 2685 suggest that the rotating helix structure is remarkably old and stable. In this sharp view of the peculiar system also known as Arp 336 or the Helix galaxy, the strange, perpendicular rings are easy to trace as they pass in front of the galactic disk, along with other disturbed outer structures. NGC 2685 is about 50,000 light-years across and 40 million light-years away in the constellation of the Great Bear (Ursa Major).   Piece it All Together: Astronomy Puzzle of the Day

Image credit: Stefan Thrun
Collapse in Hebes Chasma on Mars (2025-07-15)

What's happened in Hebes Chasma on Mars? Hebes Chasma is a depression just north of the enormous Valles Marineris canyon.  Since the depression is unconnected to other surface features, it is unclear where the internal material went. Inside Hebes Chasma is Hebes Mensa, a 5 kilometer high mesa that appears to have undergone an unusual partial collapse -- a collapse that might be providing clues. The featured image, taken by ESA's robotic Mars Express spacecraft currently orbiting Mars, shows great details of the chasm and the unusual horseshoe shaped indentation in the central mesa. Material from the mesa appears to have flowed onto the floor of the chasm, while a possible dark layer appears to have pooled like ink on a downslope landing.  One hypothesis holds that salty rock composes some lower layers in Hebes Chasma, with the salt dissolving in melted ice flows that drained through holes into an underground aquifer.
The Rosette Nebula from DECam (2025-07-16)

Would the Rosette Nebula by any other name look as sweet? The bland New General Catalog designation of NGC 2237 doesn't appear to diminish the appearance of this flowery emission nebula, as captured by the Dark Energy Camera (DECam) on the Blanco 4-meter telescope at the NSF's Cerro Tololo Inter-American Observatory in Chile.  Inside the nebula lies an open cluster of bright young stars designated NGC 2244. These stars formed about four million years ago from the nebular material and their stellar winds are clearing a hole in the nebula's center, insulated by a layer of dust and hot gas. Ultraviolet light from the hot cluster stars causes the surrounding nebula to glow. The Rosette Nebula spans about 100 light-years across, lies about 5000 light-years away, and can be seen with a small telescope towards the constellation of the Unicorn (Monoceros).   Open Science: Browse 3,700+ codes in the Astrophysics Source Code Library
3I/ATLAS (2025-07-17)

Discovered on July 1 with the NASA-funded ATLAS (Asteroid Terrestrial-impact Last Alert System) survey telescope in Rio Hurtado, Chile, 3I/ATLAS is so designated as the third known interstellar object to pass through our Solar System. It follows 1I/ʻOumuamua in 2017 and the comet 2I/Borisov in 2019.  Also known as C/2025 N1, 3I/ATLAS is clearly a comet, its diffuse cometary coma, a cloud of gas and dust surrounding an icy nucleus, is easily seen in these images from the large Gemini North telescope on Maunakea, Hawai‘i. The left panel tracks the comet as it moves across the sky against fixed background stars in successive exposures. Three different filters were used, shown in red, green, and blue. In the right panel the multiple exposures are registered and combined to form a single image of the comet. The comet's interstellar origin is also clear from its orbit, determined to be an eccentric, highly hyperbolic orbit that does not loop back around the Sun and will return 3I/ATLAS to interstellar space. Not a threat to planet Earth, the inbound interstellar interloper is now within the Jupiter's orbital distance of the Sun, while its closest approach to the Sun will bring it just within the orbital distance of Mars.
ISS Meets Saturn (2025-07-18)

This month, bright planet Saturn rises in evening skies, its rings oriented nearly edge-on when viewed from planet Earth. And in the early morning hours on July 6, it posed very briefly with the International Space Station when viewed from a location in Federal Way, Washington, USA. This well-planned image, a stack of video frames, captures their momentary conjunction in the same telescopic field of view. With the ISS in low Earth orbit, space station and gas giant planet were separated by almost 1.4 billion kilometers. Their apparent sizes are comparable but the ISS was much brighter than Saturn and the ringed planet's brightness has been increased for visibility in the stacked image. Precise timing and an exact location were needed to capture the ISS/Saturn conjunction.

Image credit: A.J. Smadi
Messier 6 (2025-07-19)

The sixth object in Charles Messier's famous catalog of things which are not comets, Messier 6 is a galactic or open star cluster. A gathering of 100 stars or so, all around 100 million years young, M6 lies some 1,600 light-years away toward the central Milky Way in the constellation Scorpius. Also cataloged as NGC 6405, the pretty star cluster's outline suggests its popular moniker, the Butterfly Cluster. Surrounded by diffuse reddish emission from the region's hydrogen gas the cluster's mostly hot and therefore blue stars are near the center of this colorful cosmic snapshot. But the brightest cluster member is a cool K-type giant star. Designated BM Scorpii it shines with a yellow-orange hue, seen near the end of one of the butterfly's antennae. This telescopic field of view spans nearly 2 Full Moons on the sky. That's 25 light-years at the estimated distance of Messier 6.

Image credit: Xinran Li
Lunar Nearside (2025-07-20)

About 1,300 images from the Lunar Reconnaissance Orbiter spacecraft's wide angle camera were used to compose this spectacular view of a familiar face - the lunar nearside. But why is there a lunar nearside? The Moon rotates on its axis and orbits the Earth at the same rate, about once every 28 days. Tidally locked in this configuration, the synchronous rotation always keeps one side, the nearside, facing Earth. As a result, featured in remarkable detail in the full resolution mosaic, the smooth, dark, lunar maria (actually lava-flooded impact basins), and rugged highlands, are well-known to earthbound skygazers. To find your favorite mare or large crater, just follow this link or slide your cursor over the picture. The LRO images used to construct the mosaic were recorded over a two week period in December 2010.
Cat's Paw Nebula from Webb Space Telescope (2025-07-21)

Nebulas are perhaps as famous for being identified with familiar shapes as perhaps cats are for getting into trouble.  Still, no known cat could have created the vast Cat's Paw Nebula visible toward the constellation of the Scorpion  (Scorpius).  At 5,700 light years distant, Cat's Paw is an emission nebula within a larger molecular cloud.  Alternatively known as the Bear Claw Nebula and cataloged as NGC 6334, stars nearly ten times the mass of our Sun have been born there in only the past few million years. Pictured here is a recently released image of the Cat's Paw taken in infrared light by the James Webb Space Telescope.  This newly detailed view into the nebula helps provide insight for how turbulent molecular clouds turn gas into stars.    Explore Your Universe: Random APOD Generator
A Double Detonation Supernova (2025-07-22)

Can some supernovas explode twice? Yes, when the first explosion acts like a detonator for the second. This is a leading hypothesis for the cause of supernova remnant (SNR) 0509-67.5.  In this two-star system, gravity causes the larger and fluffier star to give up mass to a smaller and denser white dwarf companion. Eventually the white dwarf's near-surface temperature goes so high that it explodes, creating a shock wave that goes both out and in -- and so triggers a full Type Ia supernova near the center. Recent images of the SNR 0509-67.5 system, like the featured image from the Very Large Telescope in Chile, show two shells with radii and compositions consistent with the double detonation hypothesis. This system, SNR 0509-67.5 is also famous for two standing mysteries: why its bright supernova wasn't noted 400 years ago, and why no visible companion star remains.
Fireball over Cape San Blas (2025-07-23)

Have you ever seen a fireball?  In astronomy, a fireball is a very bright meteor -- one at least as bright as Venus and possibly brighter than even a full Moon. Fireballs are rare -- if you see one you are likely to remember it for your whole life.  Physically, a fireball is a small rock that originated from an asteroid or comet that typically leaves a fading smoke trail of gas and dust as it shoots through the Earth's atmosphere.  It is unlikely that any single large ground strike occurred -- much of the rock likely vaporized as it broke up into many small pieces. The featured picture was captured last week from a deadwood beach in Cape San Blas, Florida, USA.   Piece it Back Together: Astronomy Puzzle of the Day

Image credit: Jason Rice
Titan Shadow Transit (2025-07-24)

very 15 years or so, Saturn's rings are tilted edge-on to our line of sight. As the bright, beautiful ring system grows narrower and fainter it becomes increasingly difficult to see for denizens of planet Earth. But it does provide the opportunity to watch transits of Saturn's moons and their dark shadows across the ringed gas giant's still bright disk. Of course Saturn's largest moon Titan is the easiest to spot in transit. In this telescopic snapshot from July 18, Titan itself is at the upper left, casting a round dark shadow on Saturn's banded cloudtops above the narrow rings. In fact Titan's transit season is in full swing now with shadow transits every 16 days corresponding to the moon's orbital period. Its final shadow transit will be on October 6, though Titan's pale disk will continue to cross in front of Saturn as seen from telescopes on planet Earth every 16 days through January 25, 2026.

Image credit: Every 15 years or so
Twelve Years of Kappa Cygnids (2025-07-25)

Meteors from the Kappa Cygnid meteor shower are captured in this time-lapse composite skyscape. The minor meteor shower, with a radiant not far from its eponymous star Kappa Cygni, peaks in mid-August, almost at the same time as the much better-known and better-observed Perseid meteor shower. But, seen to have a peak rate of only about 3 meteors per hour, Kappa Cygnids are vastly outnumbered by the more popular, prolific Perseid shower's meteors that emanate from the heroic constellation Perseus. To capture dozens of Kappa Cygnids, this long term astro-imaging project compiled meteors in exposures selected from over 51 August nights during the years 2012 through 2024. Most of the exposures with identified Kappa Cygnid meteors were made in August 2021, a high point of the shower's known 7-year activity cycle. All twelve years worth of Kappa Cygnids are registered against a base sea and night skyscape of the Milky Way above Elafonisi Beach, Crete, Greece, also recorded in August of 2021.

Image credit: Petr Horálek
Globular Cluster Omega Centauri (2025-07-26)

Globular star cluster Omega Centauri packs about 10 million stars much older than the Sun into a volume some 150 light-years in diameter. Also known as NGC 5139, at a distance of 15,000 light-years it's the largest and brightest of 200 or so known globular clusters that roam the halo of our Milky Way galaxy. Though most star clusters consist of stars with the same age and composition, the enigmatic Omega Cen exhibits the presence of different stellar populations with a spread of ages and chemical abundances. In fact, Omega Cen may be the remnant core of a small galaxy merging with the Milky Way. With a yellowish hue, Omega Centauri's red giant stars are easy to pick out in this sharp telescopic view.  A two-decade-long exploration of the dense star cluster with the Hubble Space Telescope has revealed evidence for a massive black hole near the center of Omega Centauri.

Image credit: Leo Shatz
Lightning over the Volcano of Water (2025-07-27)

Have you ever watched a lightning storm in awe?  You're not alone. Details of what causes lightning are still being researched, but it is known that inside some clouds, internal updrafts cause collisions between ice and snow that slowly separate charges between cloud tops and bottoms. The rapid electrical discharges that are lightning soon result.  Lightning usually takes a jagged course, rapidly heating a thin column of air to about three times the surface temperature of the Sun.  The resulting shock wave starts supersonically and decays into the loud sound known as thunder.  On average, around the world, about 6,000 lightning bolts occur between clouds and the Earth every minute. Pictured in July 2019 in a two-image composite, lightning stems from communication antennas near the top of Volcán de Agua (Volcano of Water) in Guatemala.  Sky Surprise: What picture did APOD feature on your birthday? (post 1995)
Collision at Asteroid Dimorphos (2025-07-28)

Why was this collision so strange? In 2022, to develop Earth-saving technology, NASA deliberately crashed the DART spacecraft into the asteroid moonlet Dimorphos. The hope was that this collision would alter the trajectory of Dimorphos around its parent asteroid Didymos and so demonstrate that similar collisions could, in theory, save the Earth from being hit by (other) hazardous asteroids.  But analyses of new results show that the effects of the collision are different than expected -- and we are trying to understand why.  Featured here is the time lapse video taken by the ejected LICIACube camera LUKE showing about 250 seconds of the expanding debris field of Dimorphos after the collision, with un-impacted Didymos passing in the foreground.  In 2026, Europe's Hera mission will reach the asteroids and release three spacecraft to better study the matter.
A Helix Nebula Deep Field (2025-07-29)

Is the Helix Nebula looking at you? No, not in any biological sense, but it does look quite like an eye. The Helix Nebula is so named because it also appears that you are looking down the axis of a helix. In actuality, it is now understood to have a surprisingly complex geometry, including radial filaments and extended outer loops.  The Helix Nebula (aka NGC 7293) is one of brightest and closest examples of a planetary nebula, a gas cloud created at the end of the life of a Sun-like star. The remnant central stellar core, destined to become a white dwarf star, glows in light so energetic it causes the previously expelled gas to fluoresce. The featured picture, taken in red, green, and blue but highlighted by light emitted primarily by hydrogen was created from 12 hours of exposure through a personal telescope located in Greece.  A close-up of the inner edge of the Helix Nebula shows complex gas knots the origin of which are  still being researched.    Portal Universe: Random APOD Generator

Image credit: George Chatzifrantzis
Coronal Loops on the Sun (2025-07-30)

Our Sun frequently erupts in loops.  Hot solar plasma jumps off the Sun's surface into prominences, with the most common type of prominence being a simple loop.  The loop shape originates from the Sun's magnetic field, which is traced by spiraling electrons and protons.  Many loops into the Sun's lower corona are large enough to envelop the Earth and are stable enough to last days.  They commonly occur near active regions that also include dark sunspots.  The featured panel shows four loops, each of which was captured near the Sun's edge during 2024 and 2025. The images were taken by a personal telescope in Mantova, Italy and in a very specific color of light emitted primarily by hydrogen. Some solar prominences suddenly break open and eject particles into the Solar System, setting up a space weather sequence that can affect the skies and wires of Earth.    Jigsaw Universe: Astronomy Puzzle of the Day

Image credit: Andrea Vanoni
Supernova 2025rbs in NGC 7331 (2025-07-31)

A long time ago in a galaxy 50 million light-years away, a star exploded. Light from that supernova was first detected by telescopes on planet Earth on July 14th though, and the extragalactic transient is now known to astronomers as supernova 2025rbs. Presently the brightest supernova in planet Earth's sky, 2025rbs is a Type Ia supernova, likely caused by the thermonuclear detonation of a white dwarf star that accreted material from a companion in a binary star system.  Type Ia supernovae are used as standard candles to establish the distance scale of the universe. The host galaxy of 2025rbs is NGC 7331. Itself a bright spiral galaxy in the northern constellation Pegasus, NGC 7331 is often touted as an analog to our own Milky Way.
Small Dark Nebula (2025-08-01)

A small, dark, nebula looks isolated near the center of this telescopic close-up. The wedge-shaped cosmic cloudlet lies within a relatively crowded region of space though. About 7,000 light-years distant and filled with glowing gas and an embedded cluster of young stars, the region is known as M16 or the Eagle Nebula. Hubble's iconic images of the Eagle Nebula include the famous star-forming Pillars of Creation, towering structures of interstellar gas and dust 4 to 5 light-years long. But this small dark nebula, known to some as a Bok globule, is a fraction of a light-year across. The Bok globule stands out in silhouette against the expansive background of M16's diffuse glow. Found scattered within emission nebulae and star clusters, Bok globules are small interstellar clouds of cold molecular gas and obscuring dust that also form stars within their dense, collapsing cores.

Image credit: Peter Bresseler
Fireflies, Meteors, and Milky Way (2025-08-02)

Taken on July 29 and July 30, a registered and stacked series of exposures creates this dreamlike view of a northern summer night. Multiple firefly flashes streak across the foreground as the luminous Milky Way arcs above the horizon in the Sierra de Órganos national park of central Mexico. The collection of bright streaks aligned across the sky toward the upper left in the timelapse image are Delta Aquariid meteors. Currently active, the annual Delta Aquariid meteor shower shares August nights though, overlapping with the better-known Perseid meteor shower. This year that makes post-midnight, mostly moonless skies in early August very popular with late night skygazers. How can you tell a Delta Aquariid from a Perseid meteor?  The streaks of Perseid meteors can be traced back to an apparent radiant in the constellation Perseus. Delta Aquariids appear to emerge from the more southerly constellation Aquarius, beyond the top left of this frame. Of course, the bioluminescent flashes of fireflies are common too on these northern summer nights. But how can you tell a firefly from a meteor? Just try to catch one.

Image credit: Daniel Korona
Milky Way and Exploding Meteor (2025-08-03)

In about a week the Perseid Meteor Shower will reach its maximum.  Grains of icy rock will streak across the sky as they evaporate during entry into Earth's atmosphere.  These grains were shed from Comet Swift-Tuttle.  The Perseids result from the annual crossing of the Earth through Comet Swift-Tuttle's orbit, and are typically the most active meteor shower of the year.  Although it is hard to predict the level of activity in any meteor shower, in a clear dark sky an observer might see a meteor a minute.  This year's Perseids peak just a few days after  full moon, and so some faint meteors will be lost to the lunar skyglow.  Meteor showers in general are best seen from a relaxing position, away from lights.  Featured here is a meteor caught exploding during the 2015 Perseids above Austria next to the central band of our Milky Way Galaxy.

Image credit: Andre van der Hoeven
Blue Arcs Toward Andromeda (2025-08-04)

What are these gigantic blue arcs near the Andromeda Galaxy (M31)?  Discovered in 2022 by amateur astronomers, the faint arcs -- dubbed SDSO 1 -- span nearly the same angular size as M31 itself.  At first, their origin was a mystery: are they actually near the Andromeda Galaxy, or alternatively near to our Sun?  Now, over 550 hours of combined exposure and a collaboration between amateur and professional astronomers has revealed strong evidence for their true nature: SDSO 1 is not intergalactic, but a new class of planetary nebula within our galaxy.  Dubbed a Ghost Planetary Nebula (GPN), SDSO 1 is the first recognized member of a new subclass of faded planetary nebulas, along with seven others also recently identified.  Shown in blue are extremely faint oxygen emission from the shock waves, while the surrounding red is a hydrogen-emitting trail that indicates the GPN's age.

Image credit: Ogle et 
al.
NGC 6072: A Complex Planetary Nebula from Webb (2025-08-05)

Why is this nebula so complex? The Webb Space Telescope has imaged a nebula in great detail that is thought to have emerged from a Sun-like star. NGC 6072 has been resolved into one of the more unusual and complex examples of planetary nebula. The featured image is in infrared light with the red color highlighting cool hydrogen gas. Study of previous images of NGC 6072 indicated several likely outflows and two disks inside the jumbled gas, while the new Webb image resolves new features likely including one disk's edge protruding on the central left.  A leading origin hypothesis holds that the nebula's complexity is caused or enhanced by multiple outbursts from a star in a multi-star system near the center.