juliensimon/nasa-apod huggingface dataset:
Camera Orion (2018-03-21)

Do you recognize this constellation?  Although it is one of the most recognizable star groupings on the sky, Orion's icons don't look quite as colorful to the eye as they do to a camera.  In this 20-image digitally-composed mosaic, cool red giant Betelgeuse takes on a strong orange tint as the brightest star at the upper left.  Orion's hot blue stars are numerous, with supergiant Rigel balancing Betelgeuse at the lower right, and Bellatrix at the upper right Lined up in Orion's belt are three stars all about 1,500 light-years away, born from the constellation's well-studied interstellar clouds. Below Orion's belt a reddish and fuzzy patch that might also look familiar -- the stellar nursery known as Orion's Nebula.  Finally, just barely visible to the unaided eye but quite striking here by camera is Barnard's Loop -- a huge gaseous emission nebula surrounding Orion's Belt and Nebula discovered over 100 years ago by the pioneering Orion photographer E. E. Barnard.    Follow APOD on: Facebook,  Google Plus,  Instagram, or Twitter

Image credit: Derrick Lim
NGC 253: Dusty Island Universe (2018-03-22)

Shiny NGC 253 is one of the brightest spiral galaxies visible, and also one of the dustiest.  Some call it the Silver Dollar Galaxy for its appearance in small telescopes, or just the Sculptor Galaxy for its location within the boundaries of the southern constellation Sculptor.  Discovered in 1783 by mathematician and astronomer Caroline Herschel, the dusty island universe lies a mere 10 million light-years away. About 70 thousand light-years across, NGC 253 is the largest member of the Sculptor Group of Galaxies, the nearest to our own Local Group of Galaxies.  In addition to its spiral dust lanes, tendrils of dust seem to be rising from a galactic disk laced with young star clusters and star forming regions in this sharp color image. The high dust content accompanies frantic star formation, earning NGC 253 the designation of a starburst galaxy. NGC 253 is also known to be a strong source of high-energy x-rays and gamma rays, likely due to massive black holes near the galaxy's center. Take a trip through extragalactic space in this short video flyby of NGC 253.

Image credit: Stefano Cancelli
Sharpless 249 and the Jellyfish Nebula (2018-03-23)

Normally faint and elusive, the Jellyfish Nebula is caught in this alluring telescopic image. Centered in the scene it's anchored right and left by two bright stars, Mu and Eta Geminorum, at the foot of the celestial twin. The Jellyfish Nebula is the brighter arcing ridge of emission with dangling tentacles. In fact, the cosmic jellyfish is part of bubble-shaped supernova remnant IC 443, the expanding debris cloud from a massive star that exploded. Light from the explosion first reached planet Earth over 30,000 years ago. Like its cousin in astrophysical waters the Crab Nebula supernova remnant, the Jellyfish Nebula is known to harbor a neutron star, the remnant of the collapsed stellar core. An emission nebula cataloged as Sharpless 249 fills the field at the upper left. The Jellyfish Nebula is about 5,000 light-years away. At that distance, this image would be about 300 light-years across.

Image credit: Albert Barr
NGC 602 and Beyond (2018-03-24)

Near the outskirts of the Small Magellanic Cloud, a satellite galaxy some 200 thousand light-years distant, lies 5 million year young star cluster NGC 602. Surrounded by natal gas and dust, NGC 602 is featured in this stunning Hubble image of the region, augmented by images in the X-ray by Chandra,  and in the infrared by Spitzer. Fantastic ridges and swept back shapes strongly suggest that energetic radiation and shock waves from NGC 602's massive young stars have eroded the dusty material and triggered a progression of star formation moving away from the cluster's center. At the estimated distance of the Small Magellanic Cloud, the Picture spans about 200 light-years, but a tantalizing assortment of background galaxies are also visible in this sharp multi-colored view. The background galaxies are hundreds of millions of light-years or more beyond NGC 602.
Announcing Nova Carinae 2018 (2018-03-25)

How bright will Nova Carinae 2018 become? The new nova was discovered only last week. Although novas occur frequently throughout the universe, this nova, cataloged as ASASSN-18fv, is so unusually bright in the skies of Earth that it is now easily visible through binoculars in the southern hemisphere. Identified by the arrow, the nova occurs near the direction of the picturesque Carina Nebula. A nova is typically caused by a thermonuclear explosion on the surface of a white dwarf star that is accreting matter from a binary companion, although details of this outburst are currently unknown.  Both professional and amateur astronomers will be monitoring this unusual stellar outburst in the coming weeks, looking to see how Nova Carinae 2018 evolves, including whether it becomes bright enough to be visible to the unaided eye.

Image credit: A. Maury & J. Fabrega
The Coma Cluster of Galaxies (2018-03-26)

Almost every object in the above photograph is a galaxy.  The Coma Cluster of Galaxies pictured here is one of the densest clusters known - it contains thousands of galaxies.  Each of these galaxies houses billions of stars - just as our own Milky Way Galaxy does.  Although nearby when compared to most other clusters, light from the Coma Cluster still takes hundreds of millions of years to reach us.  In fact, the Coma Cluster is so big it takes light millions of years just to go from one side to the other.  Most galaxies in Coma and other clusters are  ellipticals, while most galaxies outside of clusters are spirals.  The nature of Coma's X-ray emission is still being investigated.
Mars Between Nebulas (2018-03-27)

What's that bright red spot between the Lagoon and Trifid Nebulas?  Mars. This gorgeous color deep-sky photograph captured the red planet passing between the two notable nebulas -- cataloged by the 18th century cosmic registrar Charles Messier as M8 and M20. M20 (upper right of center), the Trifid Nebula, presents a striking contrast in red/blue colors and dark dust lanes. Across the bottom right  is the expansive, alluring red glow of M8, the Lagoon Nebula. Both nebulae are a few thousand light-years distant. By comparison, temporarily situated between them both, is the dominant "local" celestial beacon Mars. Taken last week, the red planet was only about 10 light-minutes away.   Gallery: Mars in Sagittarius

Image credit: Sebastian Voltmer
Blue Moon Tree (2018-03-28)

Does an alignment like this occur only once in a blue moon? No, although it was during a blue moon that this single-shot image was taken.  During a full moon that happened to be the second of the month -- the situation that defines a blue moon -- the photographer created the juxtaposition in late January by quickly moving around to find just the right spot to get the background Moon superposed behind the arc of a foreground tree.  Unfortunately, in this case, there seemed no other way than getting bogged down in mud and resting the camera on a barbed-wire fence.  The arc in the oak tree was previously created by hungry cows in Knight's Ferry, California, USA.  Quirky Moon-tree juxtapositions like this can be created during any full moon though, given enough planning and time.  Another opportunity will arise this weekend, coincidently during another blue moon. Then, the second blue moon in 2018 will occur, meaning that for the second month this year, two full moons will appear during a single month (moon-th).  Double blue-moon years are relatively rare, with the last occurring in 1999, and the next in 2037.

Image credit: Eric Houck
NGC 2023 in the Horsehead's Shadow (2018-03-29)

Carved by a bright young star in Orion's dusty molecular clouds, NGC 2023 is often overlooked in favor of the nearby dramatic silhouette of the Horsehead Nebula. In its own right it is seen as a beautiful star forming emission and reflection nebula though, a mere 1500 light-years distant. Surprisingly colorful and complex filaments are detailed in this rare NGC 2023 portrait. Scattered points of emission are also from the region's Herbig-Haro objects, associated with the energetic jets from newborn stars. The sharp telescopic view spans about 10 light-years at the estimated distance of NGC 2023. Off the right edge of the frame lies the more familiar cosmic Horsehead.

Image credit: Steve Mazlin
NGC 247 and Friends (2018-03-30)

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. The deep image even reveals that the two leftmost galaxies in the chain are apparently interacting, joined by a faint bridge of material. NGC 247 itself is part of the Sculptor Group of galaxies along with the shiny spiral NGC 253.

Image credit: CHART32 Team
Twilight in a Western Sky (2018-03-31)

A slender crescent Moon and inner planets Venus and Mercury never wander far from the Sun in planet Earth's skies. In the fading evening twilight of March 18, they line up near the western horizon in this atmospheric skyscape. While the celestial scene was enjoyed around the world, this photo captures the trio, with fainter Mercury at the far right, above the crags of Big Bend National Park in southwest Texas. Tonight the Moon will be full though, and rise opposite the Sun. Look for it high in the sky at midnight, near bright star Spica.

Image credit: Stan Honda
I Brought You the Moon (2018-04-01)

I love you so much that I brought you the Moon.  Please take it before this tree becomes more interested.  Also, the Moon is heavier than I thought.  And I foolishly picked it up by the hot side by mistake.  But it is for you and, well, the others reading this APOD.  Promise to keep this image -- our image -- in a safe place, and know that it was taken in a single, well-planned exposure in Valladolid, Spain.  Please take it and keep it always as a token of our love and, well, April Fool's Day.   Retrospective: April Fool's Day APODs

Image credit: Fernando Cabrerizo
Moons, Rings, Shadows, Clouds: Saturn (Cassini) (2018-04-02)

While cruising around Saturn, be on the lookout for picturesque juxtapositions of moons, rings, and shadows. One quite picturesque arrangement occurred in 2005 and was captured by the then Saturn-orbiting Cassini spacecraft. In the featured image, moons Tethys and Mimas are visible on either side of Saturn's thin rings, which are seen nearly edge-on.  Across the top of Saturn are dark shadows of the wide rings, exhibiting their impressive complexity. The violet-light image brings up the texture of the backdrop: Saturn's clouds. Cassini orbited Saturn from 2004 until September of last year, when the robotic spacecraft was directed to dive into Saturn to keep it from contaminating any moons.
The Milky Way over the Seven Strong Men Rock Formations (2018-04-03)

You may have heard of the Seven Sisters in the sky, but have you heard about the Seven Strong Men on the ground? Located just west of the Ural Mountains, the unusual Manpupuner rock formations are one of the Seven Wonders of Russia. How these ancient 40-meter high pillars formed is yet unknown.  The persistent photographer of this featured image battled rough terrain and uncooperative weather to capture these rugged stone towers in winter at night, being finally successful in February of 2014.  Utilizing the camera's time delay feature, the photographer holds a flashlight in the foreground near one of the snow-covered pillars.  High above, millions of stars shine down, while the band of our Milky Way Galaxy crosses diagonally down from the upper left.

Image credit: Sergei Makurin
Intrepid Crater on Mars from Opportunity (2018-04-04)

The robotic rover Opportunity sometimes passes small craters on Mars. Pictured here in 2010 is Intrepid Crater, a 20-meter across impact basin  slightly larger than Nereus Crater that Opportunity had chanced across previously. The featured image is in approximately true color but horizontally compressed to accommodate a wide angle panorama.  Intrepid Crater was named after the lunar module Intrepid that carried Apollo 12 astronauts to Earth's Moon 49 years ago. Beyond Intrepid Crater and past long patches of rusty Martian desert lie peaks from the rim of large Endeavour Crater, visible on the horizon.  The Opportunity rover continues to explore Mars, recently surpassing 5,000 Martian days on the red planet.
NGC 289: Swirl in the Southern Sky (2018-04-05)

About 70 million light-years distant, gorgeous spiral galaxy NGC 289 is larger than our own Milky Way. Seen nearly face-on, its bright core and colorful central disk give way to remarkably faint, bluish spiral arms. The extensive arms sweep well over 100 thousand light-years from the galaxy's center. At the lower right in this sharp, telescopic galaxy portrait the main spiral arm seems to encounter a small, fuzzy elliptical companion galaxy interacting with enormous NGC 289. Of course the spiky stars are in the foreground of the scene. They lie within the Milky Way toward the southern constellation Sculptor.

Image credit: Adam Block
NGC 3324 in Carina (2018-04-06)

This bright cosmic cloud was sculpted by stellar winds and radiation from the hot young stars of open cluster NGC 3324. With dust clouds in silhouette against its glowing atomic gas, the pocket-shaped star-forming region actually spans about 35 light-years. It lies some 7,500 light-years away toward the nebula rich southern constellation Carina. A composite of narrowband image data, the telescopic view captures the characteristic emission from ionized sulfur, hydrogen, and oxygen atoms mapped to red, green, and blue hues in the popular Hubble Palette. For some, the celestial landscape of bright ridges of emission bordered by cool, obscuring dust along the right side create a recognizable face in profile. The region's popular name is the Gabriela Mistral Nebula for the Nobel Prize winning Chilean poet.

Image credit: Martin Pugh
Painting with Jupiter (2018-04-07)

Brush strokes of Jupiter's signature atmospheric bands and vortices form this planetary post-impressionist work of art. The creative image uses actual data from the Juno spacecraft's JunoCam. To paint on the digital canvas, an image with light and dark tones was chosen for processing and an oil-painting software filter applied. The image data was captured during perijove 10, Juno's December 16, 2017 close encounter with the solar system's ruling gas giant. At the time the spacecraft was cruising about 13,000 kilometers above northern Jovian cloud tops.
NGC 6960: The Witch's Broom Nebula (2018-04-08)

Ten thousand years ago, before the dawn of recorded human history, a new light would have suddenly have appeared in the night sky and faded after a few weeks.  Today we know this light was from a supernova, or exploding star, and record the expanding debris cloud as the Veil Nebula, a supernova remnant.  This sharp telescopic view is centered on a western segment of the Veil Nebula cataloged as NGC 6960 but less formally known as the Witch's Broom Nebula.  Blasted out in the cataclysmic explosion, the interstellar shock wave plows through space sweeping up and exciting interstellar material. Imaged with narrow band filters, the glowing filaments are like long ripples in a sheet seen almost edge on, remarkably well separated into atomic hydrogen (red) and oxygen (blue-green) gas. The complete supernova remnant lies about 1400 light-years away towards the constellation Cygnus. This Witch's Broom actually spans about 35 light-years. The bright star in the frame is 52 Cygni, visible with the unaided eye from a dark location but unrelated to the ancient supernova remnant.

Image credit: Martin Pugh
(Heaven's Mirror Observatory)
The Sun Unleashed: Monster Filament in Ultraviolet (2018-04-09)

One of the most spectacular solar sights is an explosive flare. In 2011 June, the Sun unleashed somewhat impressive, medium-sized solar flare as rotation carried active regions of sunpots toward the solar limb. That flare, though, was followed by an astounding gush of magnetized plasma -- a monster filament seen erupting at the Sun's edge in this extreme ultraviolet image from NASA's Solar Dynamics Observatory. Featured here is a time-lapse video of that hours-long event showing darker, cooler plasma raining down across a broad area of the Sun's surface, arcing along otherwise invisible magnetic field lines. An associated coronal mass ejection, a massive cloud of high energy particles, was blasted in the general direction of the Earth,and made a glancing blow to Earth's magnetosphere.
Dragon Aurora over Norway (2018-04-10)

What's that in the sky? An aurora. A large coronal hole opened last month, a few days before this image was taken, throwing a cloud of fast moving electrons, protons, and ions toward the Earth. Some of this cloud impacted our Earth's magnetosphere and resulted in spectacular auroras being seen at high northern latitudes. Featured here is a particularly photogenic auroral curtain captured above Troms� Norway. To the astrophotographer, this shimmering green glow of recombining atmospheric oxygen appeared as a large dragon, but feel free to share what it looks like to you.  Although now past Solar Maximum, our Sun continues to show occasional activity creating impressive auroras on Earth visible even last week.

Image credit: Marco Bastoni
Fortuitous Flash Candidate for the Farthest Star Yet Seen (2018-04-11)

Was this flash the farthest star yet seen? An unexpected flash of light noticed fortuitously on Hubble Space Telescope images may prove to be not only an unusual gravitational lensing event but also an image of a normal star 100 times farther away than any star previously imaged individually. The featured image shows the galaxy cluster on the left complete with many yellowish galaxies, while on the right is an expanded square where a source appeared in 2016 that was not evident in 2011. The spectrum and variability of this source are strangely unlike a supernova, but rather appear more consistent with a normal blue supergiant star magnified by about a factor of 2000 by a confluence of aligned gravitational lenses.  Dubbed Icarus, the source is in a galaxy well behind the galaxy cluster and far across the universe -- at redshift 1.5.  If the lens interpretation is correct and Icarus is not an exploding star, further observations of it and other similarly magnified stars could give information about the stellar and dark matter content in the galaxy cluster and the universe.   Open Science: Browse 1,600+ codes in the Astrophysics Source Code Library
M22 and the Wanderers (2018-04-12)

Wandering through the constellation Sagittarius, bright planets Mars and Saturn appeared together in early morning skies over the last weeks. They are captured in this 3 degree wide field-of-view from March 31 in a close celestial triangle with large globular star cluster Messier 22. Of course M22 (bottom left) is about 10,000 light-years distant, a massive ball of over 100,000 stars much older than our Sun. Pale yellow and shining by reflected sunlight, Saturn (on top) is about 82 light-minutes away. Look carefully and you can spot large moon Titan as a pinpoint of light at about the 5 o'clock position in the glare of Saturn's overexposed disk. Slightly brighter and redder Mars is 9 light-minutes distant. While both planets are moving on toward upcoming oppositions, by July Mars will become much brighter still, with good telescopic views near its 2018 opposition. Then it will be a mere 3.2 light-minutes from planet Earth.

Image credit: Damian Peach
Facing NGC 3344 (2018-04-13)

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.
Martian Chiaroscuro (2018-04-14)

Deep shadows create dramatic contrasts between light and dark in this high-resolution close-up of the martian surface. Recorded on January 24, 2014 by the HiRISE camera onboard the Mars Reconnaissance Orbiter, the scene spans about 1.5 kilometers. From 250 kilometers above the Red Planet the camera is looking down at a sand dune field in a southern highlands crater. Captured when the Sun was about 5 degrees above the local horizon, only the dune crests were caught in full sunlight. A long, cold winter is coming to the southern hemisphere and bright ridges of seasonal frost line the martian dunes.
Space Shuttle Rising (2018-04-15)

What's that rising from the clouds?  The space shuttle. Sometimes, if you look out the window of an airplane at just the right time and place, you see something unusual -- in this case a space shuttle launching to orbit.   The featured image of Endeavour's final launch in 2011 May was captured from a NASA shuttle training aircraft.  Taken well above the clouds, the image can be matched with similar images of the same shuttle plume taken below the clouds.  Hot glowing gasses expelled by the engines are visible near the rising shuttle, as well as a long smoke plume.  A shadow of the plume appears on the cloud deck, indicating the direction of the Sun. The US Space Shuttle program concluded in 2011, and Endeavour can now be visited at the California Science Center.  Planned for tomorrow, however, is a different launch -- that of the Transiting Exoplanet Survey Satellite (TESS) aboard a SpaceX Falcon 9 rocket.
Flyover of Jupiter's North Pole in Infrared (2018-04-16)

What would it look like to fly over the North Pole of Jupiter? A fictional animation made from real images and data captured by NASA's Juno spacecraft shows an answer. Since the pole is presently in shadow, the video uses infrared light emitted by Jupiter -- specifically an infrared color where the hottest features glows the brightest.  As the animation starts, Juno zooms in on the enormous world.  Soon, one of the eight cyclones orbiting the North Pole is featured.  One by one, all eight cyclones circling the pole are inspected, each the size of an entire continent on Earth, and each containing bumpy and fragmented spiral walls.  The virtual trip ends with a zoom out.  Studying Jovian cyclones helps humanity to better understand dangerous storm systems that occur here on Earth.  Juno has recently concluded another close pass by Jupiter -- Perijove 12 -- and seems healthy enough to complete several more of the two-month orbits.