juliensimon/nasa-apod huggingface dataset:
Curly Spiral Galaxy M63 (2025-05-22)

A bright spiral galaxy of the northern sky, Messier 63 is nearby, about 30 million light-years distant toward the loyal constellation Canes Venatici. Also cataloged as NGC 5055, the majestic island universe is nearly 100,000 light-years across, about the size of our own Milky Way. Its bright core and majestic spiral arms lend the galaxy its popular name, The Sunflower Galaxy. This exceptionally deep exposure also follows faint loops and curling star streams far into the galaxy's halo. Extending nearly 180,000 light-years from the galactic center, the star streams are likely remnants of tidally disrupted satellites of M63. Other satellite galaxies of M63 can be spotted in the remarkable wide-field image, including dwarf galaxies, which could contribute to M63's star streams in the next few billion years.

Image credit: Alberto Pisabarro
NGC 6366 vs 47 Ophiuchi (2025-05-23)

Most globular star clusters roam the halo of our Milky Way galaxy, but globular cluster NGC 6366 lies close to the galactic plane. About 12,000 light-years away toward the constellation Ophiuchus, the cluster's starlight is dimmed and reddened by the Milky Way's interstellar dust when viewed from planet Earth. As a result, the stars of NGC 6366 look almost golden in this telescopic scene, especially when seen next to relatively bright, bluish, and nearby star 47 Ophiuchi. Compared to the hundred thousand stars or so gravitationally bound in distant NGC 6366, 47 Oph itself is a binary star system  a mere 100 light-years away. Still, the co-orbiting stars of 47 Oph are too close together to be individually distinguished in the image.

Image credit: Massimo Di Fusco
Deimos Before Sunrise (2025-05-24)

Deimos takes 30 hours and 18 minutes to complete one orbit around the Red Planet. That's a little more than one Martian day or sol which is about 24 hours and 40 minutes long, so Deimos drifts westward across the Martian sky. About 15 kilometers across at its widest, the smallest of Mars' two moons is bright though. In fact Deimos is the brightest celestial object in this Martian skyscape captured before sunrise by Perseverance on March 1, the 1,433rd sol of the Mars rover's mission. The image is a composed of 16 exposures recorded by one of the rover's navigation cameras. The individual exposures were combined into a single image for an enhanced low light view. Regulus and Algieba, bright stars in the constellation Leo, are also visible in the dark Martian predawn sky.
Beneath Jupiter (2025-05-25)

Jupiter is stranger than we knew. NASA's Juno spacecraft has now completed over 70 swoops past Jupiter as it moves around its highly elliptical orbit. Pictured from 2017, Jupiter is seen from below where, surprisingly, the horizontal bands that cover most of the planet disappear into swirls and complex patterns.  A line of white oval clouds is visible nearer to the equator.  Impressive results from Juno show that Jupiter's weather phenomena can extend deep below its cloud tops, that Jupiter's center has a core that is unexpectedly large and soft, and that Jupiter's magnetic field varies greatly with location.  Although Juno is scheduled to keep orbiting Jupiter further into 2025, at some time the robotic spacecraft will be maneuvered to plunge into the giant planet.    Jigsaw Jumble: Astronomy Puzzle of the Day

Image credit: NASA, 
Juno, 
SwRI, 
MSSS;
 Processing &
License:
Gerald Eichstädt & 
Seán Doran
Spiral Galaxy NGC 2566 from Webb (2025-05-26)

What’s happening in the center of spiral galaxy NGC 2566? First, the eight rays that appear to be coming out of the center in the featured infrared image are not real — they are diffraction spikes caused by the mechanical structure of the Webb space telescope itself. The center of NGC 2566 is bright but not considered unusual, which means that it likely contains a supermassive black hole, although currently not very active. At only 76 million light years away, the light we see from NGC 2566 today left when dinosaurs roamed the Earth. The picturesque galaxy is close enough so that Earthly telescopes, including Webb and Hubble, can resolve the turbulent clouds of gas and dust where stars can form and so allows study of stellar evolution. NGC 2566, similar in size to our Milky Way Galaxy, is notable for its bright central bar and its prominent outer spiral arms.
Zeta and Rho Ophiuchi with Milky Way (2025-05-27)

Behold one of the most photogenic regions of the night sky, captured impressively.  Featured, the band of our Milky Way Galaxy runs diagonally along the bottom-left corner, while the colorful Rho Ophiuchi cloud complex is visible just right of center and the large red circular Zeta Ophiuchi Nebula appears near the top.  In general, red emanates from nebulas glowing in the light of excited hydrogen gas, while blue marks interstellar dust preferentially reflecting the light of bright young stars.  Thick dust usually appears dark brown.  Many iconic objects of the night sky appear, including (can you find them?) the bright star Antares, the globular star cluster M4, and the Blue Horsehead nebula. This wide field composite, taken over 17 hours, was captured from South Africa last June.    Explore Your Universe: Random APOD Generator

Image credit: Ireneusz Nowak
Herbig-Haro 24 (2025-05-28)

This might look like a double-bladed lightsaber, but these two cosmic jets actually beam outward from a newborn star in a galaxy near you. Constructed from Hubble Space Telescope image data, the stunning scene spans about half a light-year across Herbig-Haro 24 (HH 24), some 1,300 light-years or 400 parsecs away in the stellar nurseries of the Orion B molecular cloud complex. Hidden from direct view, HH 24's central protostar is surrounded by cold dust and gas flattened into a rotating accretion disk. As material from the disk falls toward the young stellar object, it heats up. Opposing jets are blasted out along the system's rotation axis. Cutting through the region's interstellar matter, the narrow, energetic jets produce a series of glowing shock fronts along their path.
Irregular Dwarf Galaxy Sextans A (2025-05-29)

Grand spiral galaxies often seem to get all the attention, flaunting young, bright, blue star clusters and pinkish star forming regions along graceful, symmetric spiral arms. But small galaxies form stars too, like irregular dwarf galaxy Sextans A. Its young star clusters and star forming regions are gathered into a gumdrop-shaped region a mere 5,000 light-years across. Seen toward the navigational constellation Sextans, the small galaxy lies some 4.5 million light-years distant. That puts it near the outskirts of the local group of galaxies, that includes the large, massive spirals Andromeda and our own Milky Way. Brighter Milky Way foreground stars appear spiky and yellowish in this colorful telescopic view of Sextans A.

Image credit: Franz Hofmann
Mars in the Loop (2025-05-30)

This composite of images spaced a weather-permitting 5 to 9 days apart, from 2024 September 19 (top right) through 2025 May 18 (bottom left), faithfully traces ruddy-colored Mars as it makes a clockwise loop through the constellations Gemini and Cancer in planet Earth's night sky. You can connect the dots and dates with your cursor over the image, but be sure to check out this animation of the Red Planet's 2024/25 retrograde motion. Of course Mars didn't actually reverse the direction of its orbit. Instead, the apparent backwards motion with respect to the background stars is a reflection of the orbital motion of Earth itself. Retrograde motion can be seen each time Earth overtakes and laps planets orbiting farther from the Sun, the Earth moving more rapidly through its own relatively close-in orbit.  In this case Mars' apparent eastward motion began to reverse around December 8, when it seemed to linger near open star cluster M44 in Cancer. After wandering back to the west, under Gemini's bright stars Castor and Pollux, Mars returned to pose near M44 by early May. At its brightest near opposition on 2025 January 16, Mars was a mere 96 million kilometers away.

Image credit: Tunc Tezel
Afterimage Sunset (2025-05-31)

On May 7, the Sun setting behind a church bell tower was captured in this filtered and manipulated digital skyscape from Ragusa, Sicily, planet Earth. In this version of the image the colors look bizarre. Still, an intriguing optical illusion known as an afterimage can help you experience the same scene with a more natural looking appearance. To try it, find the sunspots of active region AR4079 grouped near the bottom of the blue solar disk. Relax and stare at the dark sunspot group for about 30 seconds, then close your eyes or shift your gaze to a plain white surface. In a moment an afterimage of the sunset should faintly appear. But the afterimage sunset will have this image's complementary colors and a more normal yellow Sun against a familiar blue sky.

Image credit: Marcella Giulia Pace
UGC 1810: Wildly Interacting Galaxy from Hubble (2025-06-01)

What's happening to this spiral galaxy? Although details remain uncertain, it surely has to do with an ongoing battle with its smaller galactic neighbor. The featured galaxy is labelled UGC 1810 by itself, but together with its collisional partner is known as Arp 273. The overall shape of UGC 1810 -- in particular its blue outer ring -- is likely a result of wild and violent gravitational interactions. This ring's blue color is caused by massive stars that are blue hot and have formed only in the past few million years.  The inner galaxy appears older, redder, and threaded with cool filamentary dust.  A few bright stars appear well in the foreground, unrelated to UGC 1810, while several galaxies are visible well in the background.  Arp 273 lies about 300 million light years away toward the constellation of Andromeda.  Quite likely, UGC 1810 will devour its galactic sidekick over the next billion years and settle into a classic spiral form.

Image credit: Domingo Pestana
Veil Nebula: Wisps of an Ancient Supernova (2025-06-02)

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 was taken in Kuwait in mid-2024 and features light emitted by hydrogen in red and oxygen in blue.  In deep images of the complete Veil Nebula like this, even studious readers might not be able to identify the iconic filaments.   Piece it All Together: Astronomy Puzzle of the Day

Image credit: Abdullah Alharbi
Rainbow Airglow over the Azores (2025-06-03)

Why would the sky glow like a giant repeating rainbow?  Airglow.  Now, air glows all of the time, but it is usually hard to see. A disturbance however -- like an approaching storm -- may cause noticeable rippling in the Earth's atmosphere. These gravity waves are oscillations in air analogous to those created when a rock is thrown in calm water.  The long-duration exposure nearly along the vertical walls of airglow likely made the undulating structure particularly visible.  OK, but where do the colors originate?  The deep red glow likely originates from OH molecules about 87 kilometers high, excited by ultraviolet light from the Sun. The orange and green airglow is likely caused by sodium and oxygen atoms slightly higher up.  The featured image was captured during a climb up Mount Pico in the Azores of Portugal.  Ground lights originate from the island of Faial in the Atlantic Ocean.  A spectacular sky is visible through this banded airglow, with the central band of our Milky Way Galaxy running up the image center, and M31, the Andromeda Galaxy, visible near the top left.   APOD Turns 30!: Free Public Lecture in Anchorage on June 11

Image credit: Miguel Claro
(TWAN);
 Rollover Annotation: 
Judy Schmidt
A Milky Road to the Rubin Observatory (2025-06-04)

Is the sky the same every night? No -- the night sky changes every night in many ways. To better explore how the night sky changes, the USA's NSF and DOE commissioned the Vera C. Rubin Observatory in Cerro Pachón, Chile. In final testing before routine operations, Rubin will begin to explore these nightly changes -- slight differences that can tell us much about our amazing universe and its surprising zoo of objects. With a mirror over 8 meters across, Rubin will continually reimage the entire visible sky every few nights to discover new supernovas, potentially dangerous asteroids, faint comets, and variable stars -- as well as mapping out the visible universe's large-scale structure.  Pictured, the distant central band of our Milky Way Galaxy appears to flow out from the newly operational observatory. Taken last month, the featured picture is a composite of 21 images across the night sky, capturing airglow on the horizon and the Small Magellanic Cloud galaxy on the lower left.    APOD Turns 30!: Free Public Lecture in Anchorage on June 11
Savudrija Star Trails (2025-06-05)

Savudrija lighthouse shines along the coast near the northern end of the Istrian peninsula in this well-composed night skyscape. A navigational aid for sailors on the Adriatic Sea, the historic lighthouse was constructed in the early 19th century. But Polaris, an even older aid to navigation, shines in the sky above. Alpha star of the constellation Ursa Minor, Polaris is also known as the North Star. In this scene Polaris forms the shortest bright arc near the North Celestial Pole, the extension of Earth's axis of rotation into space. Of course, the North Celestial Pole lies exactly at the center of all the concentric star trails. The composite image is a digital stack of 400 exposures, each 30 seconds long, taken with camera and tripod fixed to a rotating planet.

Image credit: Branko Nadj
NGC 6302: The Butterfly Nebula (2025-06-06)

The bright clusters and nebulae of planet Earth's night sky are often given the names of flowers or insects, and its whopping 3 light-year wingspan, NGC 6302 is no exception. With an estimated surface temperature of about 250,000 degrees C, the central star of the planetary nebula is transforming into a white dwarf star, becoming exceptionally hot, and shining brightly in ultraviolet light. The central star is hidden from direct view by a torus of dust, but its energetic ultraviolet light ionizes atoms in the nebula. In this sharp, telescopic view composed with narrowband image data, the ionized hydrogen and doubly ionized oxygen atoms are shown in their characteristic red and blue-green hues to reveal a stunning complex of knots and filaments within the nebula's wing-like bipolar outflows. NGC 6302 lies about 4,000 light-years away in the arachnologically correct constellation of the Scorpion (Scorpius).

Image credit: Mike Selby
Perseverance Selfie with Ingenuity (2025-06-07)

On the Mars rover's mission Sol 46 or Earth date April 6, 2021, Perseverance held out a robotic arm to take its first selfie on Mars. The WATSON camera at the end of the arm was designed to take close-ups of Martian rocks and surface details though, and not a quick snap shot of friends and smiling faces. In the end, teamwork and weeks of planning on Mars time was required to program a complex series of exposures and camera motions to include Perseverance and its surroundings. The resulting 62 frames were composed into a detailed mosaic, one of the most complicated Mars rover selfies ever taken. In this version of the selfie, the rover's Mastcam-Z and SuperCam instruments are looking toward WATSON and the end of the rover's outstretched arm. About 4 meters (13 feet) from Perseverance is a robotic companion, the Mars Ingenuity helicopter. Perseverance has now spent over 1,500 sols exploring the surface of the Red Planet. On Earth date January 18, 2024, Ingenuity made its 72nd and final flight through the thin Martian atmosphere.
Facing NGC 3344 (2025-06-08)

From our vantage point in the Milky Way Galaxy, we see NGC 3344 face-on. Nearly 40,000 light-years across, the big, beautiful spiral galaxy is located just 20 million light-years away in the constellation of Leo Minor. This multi-color Hubble Space Telescope close-up of NGC 3344 includes remarkable details from near infrared to ultraviolet wavelengths. The frame extends some 15,000 light-years across the spiral's central regions. From the core outward, the galaxy's colors change from the yellowish light of old stars in the center to young blue star clusters and reddish star forming regions along the loose, fragmented spiral arms. Of course, the bright stars with a spiky appearance are in front of NGC 3344 and lie well within our own Milky Way.   APOD Turns 30!: Free Public Lecture in Anchorage on Wednesday, June 11 at 7 pm
Between Scylla and Charybdis: A Double Cosmic Discovery (2025-06-09)

Can you identify this celestial object?  Likely not — because this is a discovery image.  Massive stars forge heavy elements in their cores and, after a few million years, end their lives in powerful supernova explosions. These remnants cool relatively quickly and fade, making them difficult to detect.  To uncover such faint, previously unknown supernova remnants, a dedicated group of amateur astrophotographers searched through sky surveys for possible supernova remnant candidates.  The result: the first-ever image of supernova remnant G115.5+9.1 — named Scylla by its discoverers—glowing faintly in the constellation of the mythological King of Aethiopia: Cepheus.  Emission from hydrogen atoms in the remnant is shown in red, and faint emission from oxygen is shown in hues of blue.  Surprisingly, another discovery lurked to the upper right: a faint, previously unknown planetary nebula candidate. In keeping with mythological tradition, it was named Charybdis (Sai 2) — a nod to the ancient Greek expression "caught between Scylla and Charybdis" from Homer’s Odyssey.
Enceladus in True Color (2025-06-10)

Do oceans under the ice of Saturn's moon Enceladus contain life?  A reason to think so involves  long features -- some dubbed tiger stripes -- that are known to be spewing ice from the moon's icy interior into space. These surface cracks create clouds of fine ice particles over the moon's South Pole and create  Saturn's mysterious E-ring.  Evidence for this has come from the robot Cassini spacecraft that orbited Saturn from 2004 to 2017.  Pictured here, a high resolution image of Enceladus is shown in true color from a close flyby.  The deep crevasses are partly shadowed.  Why Enceladus is active remains a mystery, as the neighboring moon Mimas, approximately the same size, appears quite dead. An analysis of ejected ice grains has yielded evidence that complex organic molecules exist inside Enceladus. These large carbon-rich molecules bolster -- but do not prove -- that oceans under Enceladus' surface could contain life.   APOD Turns 30!: Free public lecture in Anchorage tomorrow (Wednesday) at 7 pm
25 Brightest Stars in the Night Sky (2025-06-11)

Do you know the names of some of the brightest stars? It's likely that you do, even though some bright stars have names so old they date back to near the beginning of written language. Many world cultures have their own names for the brightest stars, and it is culturally and historically important to remember them.  In the interest of clear global communication, however, the International Astronomical Union (IAU) has begun to designate standardized star names.  Featured here in true color are the 25 brightest stars in the night sky, currently as seen by humans, coupled with their IAU-recognized names. Some star names have interesting meanings, including Sirius ("the scorcher" in Latin), Vega ("falling" in Arabic), and Antares ("rival to Mars" in Greek). You are likely even familiar with the name of at least one star too dim to make this list: Polaris.    APOD Turns 30!: Free public lecture in Anchorage TONIGHT (Wednesday) at 7 pm

Image credit: Tragoolchitr Jittasaiyapan
Solar Eclipse (2025-06-12)

On April 20, 2023 the shadow of a New Moon raced across planet Earth's southern hemisphere. When viewed along a narrow path that mostly avoided landfall, the Moon in silhouette created a hybrid solar eclipse. Hybrid eclipses are rare and can be seen as a total eclipse or an annular "ring of fire" eclipse depending on the observer's position. Viewers of this much anticipated hybrid event were able to witness a total solar eclipse while anchored in the Indian Ocean near the centerline of the eclipse track off the coast of western Australia. This ship-borne image from renowned eclipse chaser Fred Espenak captured the eclipsed Sun's magnificent outer atmosphere, or solar corona, streaming into space. The composite of 11 exposures ranging from 1/2000 to 1/2 second, taken during the 62 seconds of totality, records an extended range of brightness to follow alluring details of the corona not quite visible to the eye.  Fred Espenak (1953-2025)

Image credit: Fred Espenak
Rubin's Galaxy (2025-06-13)

In this Hubble Space Telescope image the bright, spiky stars lie in the foreground toward the heroic northern constellation Perseus and well within our own Milky Way galaxy. In sharp focus beyond is UGC 2885, a giant spiral galaxy about 232 million light-years distant. Some 800,000 light-years across compared to the Milky Way's diameter of 100,000 light-years or so, it has around 1 trillion stars. That's about 10 times as many stars as the Milky Way. Part of an investigation to understand how galaxies can grow to such enormous sizes, UGC 2885 was also part of An Interesting Voyage and American astronomer Vera Rubin's pioneering study of the rotation of spiral galaxies. Her work was the first to convincingly demonstrate the dominating presence of dark matter in our universe. A new U.S. coin has been issued to honor Vera Rubin, while the Vera C. Rubin Observatory is scheduled to unveil images from its first look at the cosmos on June 23.
Meteors and Satellite Trails over the Limay River (2025-06-14)

What are all those streaks in the sky? A galaxy, many satellite trails, and a few meteors.  First, far in the distance, the majestic band of our Milky Way Galaxy runs down the left. Mirroring it on the right are several parallel trails of Earth-orbiting Starlink satellites. Many fainter satellite trails also crisscross the image. The two short and bright streaks are meteors — likely members of the annual Eta Aquariids meteor shower.  The planet Venus shines on the lower right.  Venus and the satellites shine by reflected sunlight. The featured picture is a composite of exposures all taken in a few hours on May 4 over the Limay River in Argentina.

Image credit: Martín Moliné
Two Worlds, One Sun (2025-06-15)

How different does sunset appear from Mars than from Earth? For comparison, two images of our common star were taken at sunset, one from Earth and one from Mars. These images were scaled to have the same angular width and are featured here side-by-side. A quick inspection will reveal that the Sun appears slightly smaller from Mars than from Earth. This makes sense since Mars is 50% further from the Sun than Earth. More striking, perhaps, is that the Martian sunset is noticeably bluer near the Sun than the typically orange colors near the setting Sun from Earth. The reason for the blue hues from Mars is not fully understood, but thought to be related to forward scattering properties of Martian dust. The terrestrial sunset was taken in 2012 March from Marseille, France, while the Martian sunset was captured in 2015 by NASA's robotic Curiosity rover from Gale crater on Mars.   APOD Turns 30!: Free Public Lecture in Cork, Ireland on June 24

Image credit: Damia Bouic; 
 Right Image Credit:  NASA,
JPL-Caltech,
MSSS;
 Digital processing: 
Damia Bouic