juliensimon/nasa-apod huggingface dataset:
The Dark Tower in Scorpius (2024-08-22)

In silhouette against a crowded star field along the tail of the arachnological constellation Scorpius, this dusty cosmic cloud evokes for some the image of an ominous dark tower. In fact, monstrous clumps of dust and molecular gas collapsing to form stars may well lurk within the dark nebula, a structure that spans almost 40 light-years across this gorgeous telescopic portrait. A cometary globule, the swept-back cloud is shaped by intense ultraviolet radiation from the OB association of very hot stars in NGC 6231, off the upper right corner of the scene. That energetic ultraviolet light also powers the globule's bordering reddish glow of hydrogen gas. Hot stars embedded in the dust can be seen as bluish reflection nebulae. This dark tower and associated nebulae are about 5,000 light-years away.   Growing Gallery: Moon Eclipses Saturn in August 2024

Image credit: Mike Selby
Supernova Remnant CTA 1 (2024-08-23)

There is a quiet pulsar at the heart of CTA 1. The supernova remnant was discovered as a source of emission at radio wavelengths by astronomers in 1960 and since identified as the result of the death explosion of a massive star. But no radio pulses were detected from the expected pulsar, the rotating neutron star remnant of the massive star's collapsed core. Seen about 10,000 years after the initial supernova explosion, the interstellar debris cloud is faint at optical wavelengths. CTA 1's visible wavelength emission from still expanding shock fronts is revealed in this deep telescopic image, a frame that spans about 2 degrees across a starfield in the northern constellation of Cepheus. While no pulsar has since been found at radio wavelengths, in 2008 the Fermi Gamma-ray Space Telescope detected pulsed emission from CTA 1, identifying the supernova remnant's rotating neutron star. The source has been recognized as the first in a growing class of pulsars that are quiet at radio wavelengths but pulse in high-energy gamma-rays.

Image credit: Thomas Lelu
South Pacific Shadowset (2024-08-24)

The full Moon and Earth's shadow set together in this island skyscape. The alluring scene was captured Tuesday morning, August 20, from Fiji, South Pacific Ocean, planet Earth. For early morning risers shadowset in the western sky is a daily apparition. Still, the grey-blue shadow is often overlooked in favor of a brighter eastern horizon. Extending through the dense atmosphere, Earth's setting shadow is bounded above by a pinkish glow or anti-twilight arch. Known as the Belt of Venus, the arch's lovely color is due to backscattering of reddened light from the opposite horizon's rising Sun. Of course, the setting Moon's light is reddened by the long sight-line through the atmosphere. But on that date the full Moon could be called a seasonal Blue Moon, the third full Moon in a season with four full Moons. And even though the full Moon is always impressive near the horizon, August's full Moon is considered by some the first of four consecutive full Supermoons in 2024.

Image credit: full Moon
Fresh Tiger Stripes on Saturn's Enceladus (2024-08-25)

Do underground oceans vent through canyons on Saturn's moon Enceladus?  Long features dubbed tiger stripes are known to be spewing ice from the moon's icy interior into space, creating a cloud of fine ice particles over the moon's South Pole and creating 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 from a close flyby.  The unusual surface features dubbed tiger stripes are visible in false-color blue.  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.   Explore Your Universe: Random APOD Generator
Perseid Meteors Over Inner Mongolia (2024-08-26)

Did you see it?  One of the more common questions during a meteor shower occurs because the time it takes for a meteor to flash is similar to the time it takes for a head to turn.  Possibly, though, the glory of seeing bright meteors shoot across the sky -- while knowing that they were once small pebbles on another world -- might make it all worthwhile, even if your observing partner(s) can't always share in your experience. The featured video is composed of short clips taken in Inner Mongolia, China during the 2023 Perseid Meteor Shower. Several bright meteors were captured while live-reaction audio was being recorded -- just as the meteors flashed.  This year's 2024 Perseids also produced many beautiful meteors. Another good meteor shower to watch for is the Geminids which peak yearly in mid-December, this year with relatively little competing glow from a nearly new Moon.   Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)
Moon Eclipses Saturn (2024-08-27)

What if Saturn disappeared?  Sometimes, it does.  It doesn't really go away, though, it just disappears from view when our Moon moves in front.  Such a Saturnian eclipse, more formally called an occultation, was visible along a long swath of Earth -- from Peru, across the Atlantic Ocean, to Italy -- only a few days ago.  The featured color image is a digital fusion of the clearest images captured during the event and rebalanced for color and relative brightness between the relatively dim Saturn and the comparatively bright Moon. Saturn and the comparative bright Moon.  The exposures were all taken from Breda, Catalonia, Spain, just before occultation. Eclipses of Saturn by our Moon will occur each month for the rest of this year. Each time, though, the fleeting event will be visible only to those with clear skies -- and the right location on Earth.   Gallery: Moon Eclipses Saturn in August 2024

Image credit: Pau Montplet Sanz
Tulip Nebula and Black Hole Cygnus X-1 (2024-08-28)

When can you see a black hole, a tulip, and a swan all at once? At night -- if the timing is right, and if your telescope is pointed in the right direction.  The complex and beautiful Tulip Nebula blossoms about 8,000 light-years away toward the constellation of Cygnus the Swan.  Ultraviolet radiation from young energetic stars at the edge of the Cygnus OB3 association, including O star HDE 227018, ionizes the atoms and powers the emission from the Tulip Nebula.  Stewart Sharpless cataloged this nearly 70 light-years across reddish glowing cloud of interstellar gas and dust in 1959, as Sh2-101. Also in the featured field of view is the black hole Cygnus X-1, which is also a microquasar because it is one of strongest X-ray sources in planet Earth's sky. Blasted by powerful jets from a lurking black hole, its fainter bluish curved shock front is only faintly visible beyond the cosmic Tulip's petals, near the right side of the frame.   Back to School? Learn Science with NASA

Image credit: Anirudh Shastry
Star Factory Messier 17 (2024-08-29)

A nearby star factory known as Messier 17 lies some 5,500 light-years away in the nebula-rich constellation Sagittarius. At that distance, this 1.5 degree wide field-of-view would span about 150 light-years. In the sharp color composite image faint details of the region's gas and dust clouds are highlighted with narrowband image data against a backdrop of central Milky Way stars. The stellar winds and energetic radiation from hot, massive stars already formed from M17's stock of cosmic gas and dust have slowly carved away at the remaining interstellar material, producing the nebula's cavernous appearance and the undulating shapes within. A popular stop on telescopic tours of the cosmos, M17 is also known as the Omega or the Swan Nebula.

Image credit: Gaetan Maxant
Southern Moonscape (2024-08-30)

The Moon's south pole is toward the top left of this detailed telescopic moonscape. Captured on August 23, it looks across the rugged southern lunar highlands. The view's foreshortened perspective heightens the impression of a dense field of craters and makes the craters themselves appear more oval shaped close to the lunar limb. Prominent near center is 114 kilometer diameter crater Moretus. Moretus is young for a large lunar crater and features terraced inner walls and a 2.1 kilometer high, central peak, similar in appearance to the more northerly young crater Tycho. Mountains visible along the lunar limb at the top can rise about 6 kilometers or so above the surrounding terrain. Close to the lunar south pole, permanently shadowed crater floors with expected reservoirs of water-ice have made the rugged south polar region of the Moon a popular target for exploration.

Image credit: Lorand Fenyes
IFN and the NGC 7771 Group (2024-08-31)

Galaxies of the NGC 7771 Group are featured in this intriguing skyscape. Some 200 million light-years distant toward the constellation Pegasus, NGC 7771 is the large, edge-on spiral near center, about 75,000 light-years across, with two smaller galaxies below it. Large spiral NGC 7769 is seen face-on to the right. Galaxies of the NGC 7771 group are interacting, making repeated close passages that will ultimately result in galaxy-galaxy mergers on a cosmic timescale. The interactions can be traced by distortions in the shape of the galaxies themselves and faint streams of stars created by their mutual gravitational tides. But a clear view of this galaxy group is difficult to come by as the deep image also reveals extensive clouds of foreground dust sweeping across the field of view. The dim, dusty galactic cirrus clouds are known as Integrated Flux Nebulae. The faint IFN reflect starlight from our own Milky Way Galaxy and lie only a few hundred light-years above the galactic plane.

Image credit: Steve Mandel
The Moon Dressed Like Saturn (2024-09-01)

Why does Saturn appear so big? It doesn't -- what is pictured are foreground clouds on Earth crossing in front of the Moon. The Moon shows a slight crescent phase with most of its surface visible by reflected Earthlight, known as Da Vinci glow. The Sun directly illuminates the brightly lit lunar crescent from the bottom, which means that the Sun must be below the horizon and so the image was taken before sunrise.  This double take-inducing picture was captured on 2019 December 24, two days before the Moon slid in front of the Sun to create a solar eclipse. In the foreground, lights from small Guatemalan towns are visible behind the huge volcano Pacaya.    Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)

Image credit: Francisco Sojuel
A Triangular Prominence Hovers Over the Sun (2024-09-02)

Why is there a triangle hovering over the Sun?  Although the shape is unusual, the type of structure is not: it is part of an evolving solar prominence.  Looping magnetic fields on the Sun channel the flow of energetic particles, sometimes holding glowing gaseous structures aloft for months.  A prominence glows brightly because it contains particularly hot, dense, or opaque solar plasma. The surprising triangular structure occurred last week. Larger than our Earth, the iconic prominence was imaged by several solar photographers and documented by NASA's Solar Dynamic Observatory to form and violently dissipate in about a day. The featured image was captured in a color of red light emitted strongly by hydrogen.  Below, solar fibrils carpet the Sun's chromosphere, while the background sky is so faint in comparison that no stars are visible.  Our Sun's surface has been quite active this year.

Image credit: Andrea Vanoni
Quarter Moon and Sister Stars (2024-09-03)

Nine days ago, two quite different sky icons were imaged rising together. Specifically, Earth's Moon shared the eastern sky with the sister stars of the Pleiades cluster, as viewed from Alberta, Canada.  Astronomical images of the well-known Pleiades often show the star cluster's alluring blue reflection nebulas, but here they are washed-out by the orange moonrise sky. The half-lit Moon, known as a quarter moon, is overexposed, although the outline of the dim lunar night side can be seen by illuminating earthshine, light first reflected from the Earth. The featured image is a composite of eight successive exposures with brightnesses adjusted to match what the human eye would see.  The Moon passes nearly -- or directly -- in front of the Pleaides once a month.

Image credit: Alan Dyer, 
TWAN
NGC 6995: The Bat Nebula (2024-09-04)

Can you see the bat?  It haunts this cosmic close-up of the eastern Veil Nebula.  The Veil Nebula itself is a large supernova remnant, the expanding debris cloud from the death explosion of a massive star. While the Veil is roughly circular in shape and covers nearly 3 degrees on the sky toward the constellation of the Swan (Cygnus), NGC 6995, known informally as the Bat Nebula, spans only 1/2 degree, about the apparent size of the Moon. That translates to 12 light-years at the Veil's estimated distance, a reassuring 1,400 light-years from planet Earth. In the composite of image data recorded through narrow band filters, emission from hydrogen atoms in the remnant is shown in red with strong emission from oxygen atoms shown in hues of blue. Of course, in the western part of the Veil lies another seasonal apparition: the Witch's Broom Nebula.   Teachers & Students: Ideas for using APOD in the classroom

Image credit: Mike Taivalmaa
NGC 247 and Friends (2024-09-05)

About 70,000 light-years across, NGC 247 is a spiral galaxy smaller than our Milky Way. Measured to be only 11 million light-years distant it is nearby though. Tilted nearly edge-on as seen from our perspective, it dominates this telescopic field of view toward the southern constellation Cetus. The pronounced void on one side of the galaxy's disk recalls for some its popular name, the Needle's Eye galaxy. Many background galaxies are visible in this sharp galaxy portrait, including the remarkable string of four galaxies just below and left of NGC 247 known as Burbidge's Chain. Burbidge's Chain galaxies are about 300 million light-years distant. NGC 247 itself is part of the Sculptor Group of galaxies along with shiny spiral NGC 253.

Image credit: Eric Benson
Ringed Ice Giant Neptune (2024-09-06)

Ringed ice giant Neptune lies near the center of this sharp near-infrared image from the James Webb Space Telescope. The dim and distant world is the farthest planet from the Sun, about 30 times farther away than planet Earth. But in the stunning Webb view, the planet's dark and ghostly appearance is due to atmospheric methane that absorbs infrared light. High altitude clouds that reach above most of Neptune's absorbing methane easily stand out in the image though. Coated with frozen nitrogen, Neptune's largest moon Triton is brighter than Neptune in reflected sunlight, seen at the upper left sporting the Webb telescope's characteristic diffraction spikes. Including Triton, seven of Neptune's 14 known moons can be identified in the field of view. Neptune's faint rings are striking in this space-based planetary portrait. Details of the complex ring system are seen here for the first time since Neptune was visited by the Voyager 2 spacecraft in August 1989.
Small Moon Deimos (2024-09-07)

Mars has two tiny moons, Phobos and Deimos, named for the figures in Greek mythology Fear and Panic. Detailed surface views of smaller moon Deimos are shown in both these panels. The images were taken in 2009, by the HiRISE camera on board the Mars Reconnaissance Orbiter spacecraft, NASA's long-lived interplanetary internet satellite. The outermost of the two Martian moons, Deimos is one of the smallest known moons in the Solar System, measuring only about 15 kilometers across.  Both Martian moons were discovered in 1877 by Asaph Hall, an American astronomer working at the US Naval Observatory in Washington D.C. But their existence was postulated around 1610 by Johannes Kepler, the astronomer who derived the laws of planetary motion. In this case, Kepler's prediction was not based on scientific principles, but his writings and ideas were so influential that the two Martian moons are discussed in works of fiction such as Jonathan Swift's Gulliver's Travels, written in 1726, over 150 years before their discovery.
M31: The Andromeda Galaxy (2024-09-08)

The most distant object easily visible to the unaided eye is M31, the great Andromeda Galaxy. Even at some two and a half million light-years distant, this immense spiral galaxy -- spanning over 200,000 light years -- is visible, although as a faint, nebulous cloud in the constellation Andromeda. A bright yellow nucleus, dark winding dust lanes, and expansive spiral arms dotted with blue star clusters and red nebulae, are recorded in this stunning telescopic image which combines data from orbiting Hubble with ground-based images from Subaru and Mayall. In only about 5 billion years, the Andromeda galaxy may be even easier to see -- as it will likely span the entire night sky -- just before it merges with, or passes right by, our Milky Way Galaxy.   Teachers & Students: Ideas for using APOD in the classroom

Image credit: R. Gendler & 
R. Croman
Mars: Moon, Craters, and Volcanos (2024-09-09)

If you could fly over Mars, what might you see? The featured image shows exactly this in the form of a Mars Express vista captured over a particularly interesting region on Mars in July. The picture's most famous feature is Olympus Mons, the largest volcano in the Solar System, visible on the upper right.  Another large Martian volcano is visible on the right horizon: Pavonis Mons. Several circular impact craters can be seen on the surface of the aptly named red planet. Impressively, this image was timed to capture the dark and doomed Martian moon Phobos, visible just left of center.  The surface feature on the lower left, known as Orcus Patera, is unusual for its large size and oblong shape, and mysterious because the processes that created it still remain unknown.  ESA's robotic Mars Express spacecraft was launched in 2003 and, among many notable science discoveries, bolstered evidence that Mars was once home to large bodies of water.
Horsehead and Orion Nebulas (2024-09-10)

The dark Horsehead Nebula and the glowing Orion Nebula are contrasting cosmic vistas. Adrift 1,500 light-years away in one of the night sky's most recognizable constellations, they appear in opposite corners of the above stunning mosaic. The familiar Horsehead nebula appears as a dark cloud, a small silhouette notched against the long glow of hydrogen -- here shown in gold -- at the lower left. Alnitak is the easternmost star in Orion's belt and is seen as the bright star to the left of the Horsehead. Just below Alnitak is the Flame Nebula, with clouds of bright emission and dramatic dark dust lanes. The magnificent emission region, the Orion Nebula (aka M42), lies at the upper right. Immediately to its left is a prominent reflection nebula sometimes called the Running Man. Pervasive tendrils of glowing hydrogen gas are easily traced throughout the region.   Astrophysicists: Browse 3,500+ codes in the Astrophysics Source Code Library

Image credit: Antoine & Dalia Grelin
A Night Sky over the Tatra Mountains (2024-09-11)

A natural border between Slovakia and Poland is the Tatra Mountains. A prominent destination for astrophotographers, the Tatras are the highest mountain range in the Carpathians. In the featured image taken in May, one can see the center of our Milky Way galaxy with two of its famous stellar nurseries, the Lagoon and Omega Nebula, just over the top of the Tatras. Stellar nurseries are full of ionized hydrogen, a fundamental component for the formation of Earth-abundant water. As a fundamental ingredient in all known forms of life, water is a crucial element in the Universe. Such water can be seen in the foreground in the form of the Bialka River.   Portal Universe: Random APOD Generator
Young Star Cluster NGC 1333 (2024-09-12)

This spectacular mosaic of images from the James Webb Space Telescope peers into the heart of young star cluster NGC 1333. A mere 1,000 light-years distant toward the heroic constellation Perseus, the nearby star cluster lies at the edge of the large Perseus molecular cloud. Part of Webb's deep exploration of the region to identify low mass brown dwarf stars and free floating planets, the space telescope's combined field of view spans nearly 2 light-years across the dusty cluster's turbulent stellar nursery. In fact, NGC 1333 is known to harbor stars less than a million years old, though most are hidden from optical telescopes by the pervasive stardust. The chaotic environment may be similar to one in which our own Sun formed over 4.5 billion years ago.
Aurora Australis and the International Space Station (2024-09-13)

This snapshot from the International Space Station was taken on August 11 while orbiting about 430 kilometers above the Indian Ocean, Southern Hemisphere, planet Earth. The spectacular view looks south and east, down toward the planet's horizon and through red and green curtains of aurora australis. The auroral glow is caused by emission from excited oxygen atoms in the extremely rarefied upper atmosphere still present at the level of the orbiting outpost. Green emission from atomic oxygen dominates this scene at altitudes of 100 to 250 kilometers, while red emission from atomic oxygen can extend as high as 500 kilometers altitude. Beyond the glow of these southern lights, this view from low Earth orbit reveals the starry sky from a southern hemisphere perspective. Stars in Orion's belt and the Orion Nebula are near the Earth's limb just left of center. Sirius, alpha star of Canis Major and brightest star in planet Earth's night is above center along the right edge of the southern orbital skyscape.  Looking Up: International Observe the Moon Night
The Moona Lisa (2024-09-14)

Only natural colors of the Moon in planet Earth's sky appear in this creative visual presentation. Arranged as pixels in a framed image, the lunar disks were photographed at different times. Their varying hues are ultimately due to reflected sunlight affected by changing atmospheric conditions and the alignment geometry of Moon, Earth, and Sun. Here, the darkest lunar disks are the colors of earthshine. A description of earthshine, in terms of sunlight reflected by Earth's oceans illuminating the Moon's dark surface, was written over 500 years ago by Leonardo da Vinci.  But stand farther back from your screen or just shift your gaze to the smaller versions of the image. You might also see one of da Vinci's most famous works of art.  Tonight: International Observe the Moon Night

Image credit: Gianni Sarcone
Find the Man in the Moon (2024-09-15)

Have you ever seen the Man in the Moon? This common question plays on the ability of humans to see pareidolia -- imagining familiar icons where they don't actually exist. The textured surface of Earth's full Moon is home to numerous identifications of iconic objects, not only in modern western culture but in world folklore throughout history. Examples, typically dependent on the Moon's perceived orientation, include the Woman in the Moon and the Rabbit in the Moon. One facial outline commonly identified as the Man in the Moon starts by imagining the two dark circular areas -- lunar maria -- here just above the Moon's center, to be the eyes.  Surprisingly, there actually is a man in this Moon image -- a close look will reveal a real person -- with a telescope -- silhouetted against the Moon. This well-planned image was taken in 2016 in Cadalso de los Vidrios in Madrid, Spain.   Observe the Moon Night: NASA Coverage

Image credit: Dani Caxete