juliensimon/nasa-apod huggingface dataset:
Orion Nebula in Surrounding Dust (2014-03-25)

What surrounds a hotbed of star formation?  In the case of the Orion Nebula -- dust.  The entire Orion field, located about 1600 light years away, is inundated with intricate and picturesque filaments of dust. Opaque to visible light, dust is created in the outer atmosphere of massive cool stars and expelled by a strong outer wind of particles. The Trapezium and other forming star clusters are embedded in the nebula. The intricate filaments of dust surrounding M42 and M43 appear gray in the above image, while central glowing gas is highlighted in brown and blue. Over the next few million years much of Orion's dust will be slowly destroyed by the very stars now being formed, or dispersed into the Galaxy.    Help Wanted: APOD Assessment Officer

Image credit: Robert Fields
M78 and Reflecting Dust Clouds (2014-03-26)

An eerie blue glow and ominous columns of dark dust highlight M78 and other bright reflection nebula in the constellation of Orion.  The dark filamentary dust not only absorbs light, but also reflects the light of several bright blue stars that formed recently in the nebula.  Of the two reflection nebulas pictured above, the more famous nebula is M78, in the image center, while NGC 2071 can be seen to its lower left. The same type of scattering that colors the daytime sky further enhances the blue color.  M78 is about five light-years across and visible through a small telescope.  M78 appears above only as it was 1600 years ago, however, because that is how long it takes light to go from there to here.  M78 belongs to the larger Orion Molecular Cloud Complex that contains the Great Nebula in Orion and the Horsehead Nebula.   Follow APOD on: Facebook,  Google Plus, or Twitter

Image credit: Ian Sharp
Stephan's Quintet Plus One (2014-03-27)

The first identified compact galaxy group, Stephan's Quintet is featured in this remarkable image constructed with data drawn from Hubble Legacy Archive and the Subaru Telescope on the summit of Mauna Kea. The galaxies of the quintet are gathered near the center of the field, but really only four of the five are locked in a cosmic dance of repeated close encounters taking place some 300 million light-years away. The odd man out is easy to spot, though. The interacting galaxies, NGC 7319, 7318A, 7318B, and 7317 have a more dominant yellowish cast. They also tend to have distorted loops and tails, grown under the influence of disruptive gravitational tides. The mostly bluish galaxy, NGC 7320, is in the foreground about 40 million light-years distant, and isn't part of the interacting group. Still, captured in this field above and to the left of Stephan's Quintet is another galaxy, NGC 7320C, that is also 300 million light-years distant. Of course, including it would bring the four interacting galaxies back up to quintet status. Stephan's Quintet lies within the boundaries of the high flying constellation Pegasus. At the estimated distance of the quintet's interacting galaxies, this field of view spans over 500,000 light-years.
Stripping ESO 137-001 (2014-03-28)

Spiral galaxy ESO 137-001 hurtles through massive galaxy cluster Abell 3627 some 220 million light years away. The distant galaxy is seen in this colorful Hubble/Chandra composite image through a foreground of the Milky Way's stars toward the southern constellation Triangulum Australe. As the spiral speeds along at nearly 7 million kilometers per hour, its gas and dust are stripped away when ram pressure with the cluster's own hot, tenuous intracluster medium overcomes the galaxy's gravity. Evident in Hubble's near visible light data, bright star clusters have formed in the stripped material along the short, trailing blue streaks. Chandra's X-ray data shows off the enormous extent of the heated, stripped gas as diffuse, darker blue trails stretching over 400,000 light-years toward the bottom right. The significant loss of dust and gas will make new star formation difficult for this galaxy. A yellowish elliptical galaxy, lacking in star forming dust and gas, is just to the right of ESO 137-001 in the frame.
A Milky Way Dawn (2014-03-29)

As dawn broke on March 27, the center of the Milky Way Galaxy stood almost directly above the European Southern Observatory's Paranal Observatory. In the dry, clear sky of Chile's Atacama desert, our galaxy's dusty central bulge is flanked by Paranal's four 8 meter Very Large Telescope units in this astronomical fisheye view. Along the top, Venus is close to the eastern horizon. The brilliant morning star shines very near a waning crescent Moon just at the edge of one of the telescope structures. Despite the bright pairing in the east, the Milky Way dominates the scene though. Cut by dust lanes and charged with clouds of stars and glowing nebulae, the center of our galaxy sprawls across the darker zenith even as the deep blue sky grows brighter and buildings still glint in moonlight.

Image credit: Babak Tafreshi
Io in True Color (2014-03-30)

The strangest moon in the Solar System is bright yellow.  This picture, an attempt to show how Io would appear in the "true colors" perceptible to the average human eye, was taken in 1999 July by the Galileo spacecraft that orbited Jupiter from 1995 to 2003.  Io's colors derive from sulfur and molten silicate rock.  The unusual surface of Io is kept very young by its system of active volcanoes.  The intense tidal gravity of Jupiter stretches Io and damps wobbles caused by Jupiter's other Galilean moons.  The resulting friction greatly heats Io's interior, causing  molten rock to explode through the surface.  Io's volcanoes are so active that they are effectively turning the whole moon inside out.  Some of Io's volcanic lava is so hot it  glows in the dark.    Follow APOD on: Facebook,  Google Plus, or Twitter
2012 VP113: A New Furthest Known Orbit in the Solar System (2014-03-31)

What object has the furthest known orbit in our Solar System? In terms of how close it will ever get to the Sun, the new answer is 2012 VP113, an object currently over twice the distance of Pluto from the Sun.  Pictured above is a series of discovery images taken with the Dark Energy Camera attached to the NOAO's Blanco 4-meter Telescope in Chile in 2012 and released last week. The distant object, seen moving on the lower right, is thought to be a dwarf planet like Pluto. Previously, the furthest known dwarf planet was Sedna, discovered in 2003. Given how little of the sky was searched, it is likely that as many as 1,000 more objects like 2012 VP113 exist in the outer Solar System. 2012 VP113 is currently near its closest approach to the Sun, in about 2,000 years it will be over five times further. Some scientists hypothesize that the reason why objects like Sedna and 2012 VP113 have their present orbits is because they were gravitationally scattered there by a much larger object -- possibly a very distant undiscovered planet.
Space Station Robot Forgets Key Again (2014-04-01)

Space station robot AFJ013 has forgotten her space lock key again. The frustrated robot was reduced to tapping on a space station window and asking for a human to let her back in -- for the third time this week. "Yes, she did a great job adjusting the tolerances on the new science module, but why she can't remember to take her key is beyond me," said incredulous station commander Koichi Wakata (Japan). "We would keep the entry unlocked but we are afraid that space aliens will come in and raid our refrigerator", the astronaut lamented. Happy April Fools' Day from the folks at APOD.  In reality, International Space Station astronaut Wakata poses in front of a Cupola window while the Latching End Effector, attached to Canadarm2, is visible just outside.
Mars Red and Spica Blue (2014-04-02)

A bright pair of sky objects will be visible together during the next few months. Mars will shine brightly in its familiar rusty hue as it reaches its brightest of 2014 next week. The reason that Mars appears so bright is that Earth and Mars are close to each other in their long orbits around the Sun. Spica, on the other hand, shines constantly as one of the brightest blue stars in the night sky. Pronounced "spy-kah", the blue-hued star has been visible throughout human history and the sounds that identify it today date back to ancient times. Pictured above, the planet and the star were photographed rising together toward the southeast after sunset last week through old oak trees in Sweden.   Click Hyperspace: Random APOD Generator

Image credit: Clear Skies
At the Edge of NGC 2174 (2014-04-03)

This fantastic skyscape lies near the edge of NGC 2174 a star forming region about 6,400 light-years away in the nebula-rich constellation of Orion. It follows mountainous clouds of gas and dust carved by winds and radiation from the region's newborn stars, now found scattered in open star clusters embedded around the center of NGC 2174, off the top of the frame. Though star formation continues within these dusty cosmic clouds they will likely be dispersed by the energetic newborn stars within a few million years. Recorded at infrared wavelengths by the Hubble Space Telescope, the interstellar scene spans about 6 light-years. The image celebrates the upcoming 24th anniversary of Hubble's launch onboard the space shuttle orbiter Discovery on April 24, 1990.
Along the Western Veil (2014-04-04)

Delicate in appearance, these filaments of shocked, glowing gas, draped in planet Earth's sky toward the constellation of Cygnus, make up the western part of the Veil Nebula. The Veil Nebula itself is a large supernova remnant, an expanding cloud born of the death explosion of a massive star. Light from the original supernova explosion likely reached Earth over 5,000 years ago. Blasted out in the cataclysmic event, the interstellar shock wave plows through space sweeping up and exciting interstellar material.  The glowing filaments are really more like long ripples in a sheet seen almost edge on, remarkably well separated into atomic hydrogen (red) and oxygen (blue-green) gas. Also known as the Cygnus Loop, the Veil Nebula now spans nearly 3 degrees or about 6 times the diameter of the full Moon. While that translates to over 70 light-years at its estimated distance of 1,500 light-years, this wide image of the western portion spans about half that distance. Brighter parts of the western Veil are recognized as separate nebulae, including The Witch's Broom (NGC 6960) along the top of this view and Pickering's Triangle (NGC 6979) below and right of center.
Lunar Farside (2014-04-05)

Tidally locked in synchronous rotation, the Moon always presents its familiar nearside to denizens of planet Earth. From lunar orbit, the Moon's farside can become familiar, though. In fact this sharp picture, a mosaic from the Lunar Reconnaissance Orbiter's wide angle camera, is centered on the lunar farside. Part of a global mosaic of over 15,000 images acquired between November 2009 and February 2011, the highest resolution version shows features at a scale of 100 meters per pixel. Surprisingly, the rough and battered surface of the farside looks very different from the nearside covered with smooth dark lunar maria.  The likely explanation is that the farside crust is thicker, making it harder for molten material from the interior to flow to the surface and form the smooth maria.
Fresh Tiger Stripes on Saturn's Enceladus (2014-04-06)

Do underground oceans vent through the tiger stripes 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 now orbiting Saturn.  Pictured above, 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. Most recently, an analysis of slight gravity deviations has given an independent indication of underground oceans.  Such research is particularly interesting since such oceans would be candidates to contain life.
A Solar Eclipse from the Moon (2014-04-07)

Has a solar eclipse ever been seen from the Moon? Yes, first in 1967 -- but it may happen again next week.  The robotic Surveyor 3 mission took thousands of wide angle television images of the Earth in 1967, a few of which captured the Earth moving in front of the Sun.  Several of these images have been retrieved from the NASA archives and compiled into the above time-lapse video.  Although the images are grainy, the Earth's atmosphere clearly refracted sunlight around it and showed a beading effect when some paths were blocked by clouds. Two years later, in 1969, the Apollo 12 crew saw firsthand a different eclipse of the Sun by the Earth on the way back from the Moon.  In 2009, Japan's robotic Kaguya spacecraft took higher resolution images of a similar eclipse while orbiting the Moon.  Next week, however, China's Chang'e 3 mission, including its Yutu rover, might witness a new total eclipse of the Sun by the Earth from surface of the Moon.  Simultaneously, from lunar orbit, NASA's LADEE mission might also capture the unusual April 15 event. Another angle of this same event will surely be visible to people on Earth -- a total lunar eclipse.
M42: Inside the Orion Nebula (2014-04-08)

The Great Nebula in Orion, an immense, nearby starbirth region, is probably the most famous of all astronomical nebulas.  Here, glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud only 1500 light-years away.  In the above deep image composite in assigned colors taken by the Hubble Space Telescope wisps and sheets of dust and gas are particularly evident.  The Great Nebula in Orion can be found with the unaided eye near the easily identifiable belt of three stars in the popular constellation Orion.  In addition to housing a bright open cluster of stars known as the Trapezium, the Orion Nebula contains many stellar nurseries.   These nurseries contain much hydrogen gas, hot young stars, proplyds, and stellar jets spewing material at high speeds.  Also known as M42, the Orion Nebula spans about 40 light years and is located in the same spiral arm of our Galaxy as the Sun.    Astrophysicists: Browse 750+ codes in the Astrophysics Source Code Library
Two Rings for Asteroid Chariklo (2014-04-09)

Asteroids can have rings. In a surprising discovery announced two weeks ago, the distant asteroid 10199 Chariklo was found to have at least two orbiting rings. Chariklo's diameter of about 250 kilometers makes it the largest of the measured centaur asteroids, but now the smallest known object to have rings. The centaur-class minor planet orbits the Sun between Saturn and Uranus. The above video gives an artist's illustration of how the rings were discovered. As Chariklo passed in 2013 in front of a faint star, unexpected but symmetric dips in the brightness of the star revealed the rings. Planetary astronomers are now running computer simulations designed to investigate how Chariklo's unexpected ring system might have formed, how it survives, and given the asteroid's low mass and close passes of other small asteroids and the planet Uranus, how long it may last.
Mars, Ceres, Vesta (2014-04-10)

That bright, ruddy star you've recently noticed rising just after sunset isn't a star at all. That's Mars, the Red Planet. Mars is now near its 2014 opposition (April 8) and closest approach (April 14), looping through the constellation Virgo opposite the Sun in planet Earth's sky. Clearly outshining bluish Spica, alpha star of Virgo, Mars is centered in this labeled skyview from early April, that includes two other solar system worlds approaching their opposition. On the left, small and faint asteroid Vesta and dwarf planet Ceres are seen near star Tau Virginis. But you'll just have to imagine NASA's Dawn spacecraft cruising between the small worlds. Having left Vesta in September of 2012, Dawn's ion engine has been steadily driving it to match orbits with Ceres, scheduled to arrive there in February 2015. Of course, you can also look near Mars for the Moon opposite the Sun in Earth's sky on the night of April 14/15 ... and see a total lunar eclipse.

Image credit: Tunç Tezel
Mars near Opposition (2014-04-11)

Tonight Mars is between opposition (April 8) and closest approach (April 14) looping through the constellation Virgo opposite the Sun in the night sky. That makes it prime season for telescopic views of the the Red Planet, like this one from April 3rd. The clear, sharp image was captured with a high-speed digital camera and 16-inch diameter telescope from Assis, Brazil, Planet Earth. Mars' north polar cap is at the top left. Also visible are whitish orographic clouds - water vapor clouds condensing in the cold atmosphere above the peaks of Mars' towering volcanos.  The exact dates of closest approach and opposition are slightly different because of the planet's elliptical orbit. Still, get your telescope out on the night of closest approach (April 14/15) and you can view both Mars and a total eclipse of the Moon. Mars will be about 1/100th the angular size of the Moon.

Image credit: Fabio Carvalho
and Gabriela Carvalho
Clouds and Crosses over Haleakala (2014-04-12)

Aloha and welcome to a breathtaking skyscape. The dreamlike panoramic view from March 27 looks out over the 10,000 foot summit of Haleakala on Maui, Hawai'i. A cloud layer seeps over the volcanic caldera's edge with the Milky Way and starry night sky above. Head of the Northern Cross asterism, supergiant star Deneb lurks within the Milky Way's dust clouds and nebulae at the left. From there you can follow the arc of the Milky Way all the way to the stars of the more compact Southern Cross, just above the horizon at the far right. Bright Saturn is near the top right of the frame, with red giant Antares below it and left, closer to the Milky Way's central bulge. Need some help identifying the stars? Just slide your cursor over the picture, or download this labeled panorama.  (Editor's Note: After some more help identifying the stars, the identification of Mars in the original posting was replaced with Saturn - updated April 15.)

Image credit: Wally Pacholka
Saturn in Blue and Gold (2014-04-13)

Why is Saturn partly blue?  The above picture of Saturn approximates what a human would see if hovering close to the giant ringed world.   The above picture was taken in 2006 March by the robot Cassini spacecraft now orbiting Saturn.  Here Saturn's majestic rings appear directly only as a thin vertical line.  The rings show their complex structure in the dark shadows they create on the image left.   Saturn's fountain moon Enceladus, only about 500 kilometers across, is seen as the bump in the plane of the rings.  The northern hemisphere of Saturn can appear partly blue for the same reason that Earth's skies can appear blue -- molecules in the cloudless portions of both planet's atmospheres are better at scattering blue light than red.  When looking deep into Saturn's clouds, however, the natural gold hue of Saturn's clouds becomes dominant.   It is not known why southern Saturn does not show the same blue hue -- one hypothesis holds that clouds are higher there.   It is also not known why Saturn's clouds are colored gold.
An Unusual Globule in IC 1396 (2014-04-14)

Is there a monster in IC 1396?  Known to some as the Elephant's Trunk Nebula, parts of gas and dust clouds of this star formation region may appear to take on foreboding forms, some nearly human.  The only real monster here, however, is a bright young star too far from Earth to hurt us.  Energetic light from this star is eating away the dust of the dark cometary globule near the top of the above image.  Jets and winds of particles emitted from this star are also pushing away ambient gas and dust.  Nearly 3,000 light-years distant, the relatively faint IC 1396 complex covers a much larger region on the sky than shown here, with an apparent width of more than 10 full moons.   Tonight: April 15, 2AM EDT - Lunar Eclipse | Times

Image credit: T. Rector
Mammatus Clouds over Nebraska (2014-04-15)

When do cloud bottoms appear like bubbles? Normally, cloud bottoms are flat. This is because moist warm air that rises and cools will condense into water droplets at a specific temperature, which usually corresponds to a very specific height.  As water droplets grow, an opaque cloud forms.  Under some conditions, however, cloud pockets can develop that contain large droplets of water or ice that fall into clear air as they evaporate.  Such pockets may occur in turbulent air near a thunderstorm.  Resulting mammatus clouds can appear especially dramatic if sunlit from the side.  The mammatus clouds pictured above were photographed over Hastings, Nebraska during 2004 June.

Image credit: Jorn Olsen Photography
Spica, Mars, and Eclipsed Moon (2014-04-16)

A beautiful, reddened Moon slid through dark skies on April 15, completely immersed in Earth's shadow for well over an hour. It was the year's first total lunar eclipse and was widely enjoyed over the planet's Western Hemisphere. Seen from the Caribbean island of Barbados, the dimmed lunar disk is captured during totality in this colorful skyview. The dark Moon's red color contrasts nicely with bright bluish star Spica, alpha star of the constellation Virgo, posing only about two degrees away. Brighter than Spica and about 10 degrees from the Moon on the right, Mars is near opposition and closest approach to Earth. The Red Planet's own ruddy hue seems to echo the color of the eclipsed Moon.

Image credit: Damian Peach
Waterton Lake Eclipse (2014-04-17)

Recorded on April 15th, this total lunar eclipse sequence looks south down icy Waterton Lake from the Waterton Lakes National Park in Alberta, Canada, planet Earth. The most distant horizon includes peaks in Glacier National Park, USA. An exposure every 10 minutes captured the Moon's position and eclipse phase, as it arced, left to right, above the rugged skyline and Waterton town lights. In fact, the sequence effectively measures the roughly 80 minute duration of the total phase of the eclipse. Around 270 BC, the Greek astronomer Aristarchus also measured the duration of lunar eclipses - though probably without the benefit of digital clocks and cameras. Still, using geometry, he devised a simple and impressively accurate way to calculate the Moon's distance, in terms of the radius of planet Earth, from the eclipse duration. This modern eclipse sequence also tracks the successive positions of Mars, above and right of the Moon, bright star Spica next to the reddened lunar disk, and Saturn to the left and below.

Image credit: Yuichi Takasaka
Red Moon, Green Beam (2014-04-18)

This is not a scene from a sci-fi special effects movie. The green beam of light and red lunar disk are real enough, captured in the early morning hours of April 15. Of course, the reddened lunar disk is easy to explain as the image was taken during this week's total lunar eclipse. Immersed in shadow, the eclipsed Moon reflects the dimmed reddened light of all the sunsets and sunrises filtering around the edges of planet Earth, seen in silhouette from a lunar perspective. But the green beam of light really is a laser. Shot from the 3.5-meter telescope at Apache Point Observatory in southern New Mexico, the beam's path is revealed as Earth's atmosphere scatters some of the intense laser light. The laser's target is the Apollo 15 retroreflector, left on the Moon by the astronauts in 1971. By determining the light travel time delay of the returning laser pulse, the experimental team from UC San Diego is able to measure the Earth-Moon distance to millimeter precision and provide a test of General Relativity, Einstein's theory of gravity. Conducting the lunar laser ranging experiment during a total eclipse uses the Earth like a cosmic light switch. With direct sunlight blocked, the reflector's performance is improved over performance when illuminated by sunlight during a normal Full Moon, an effect known as the real Full Moon Curse.

Image credit: Apache Point Observatory