juliensimon/nasa-apod huggingface dataset:
Apollo 11: Onto a New World (2009-07-20)

A human first set foot on another world on July 20, 1969.  This world was Earth's own Moon.  In honor of today's 40th anniversary, NASA has released a digitally restored video of this milestone in human history.  Pictured above is Neil Armstrong preparing to take the historic first step. On the way down the Lunar Module ladder, Armstrong released equipment which included the television camera that recorded this fuzzy image.  Pictures and voice transmissions were broadcast live to a world wide audience estimated at one fifth of the world's population.  The Apollo Moon landings have since been described as the greatest technological achievement the world has known.
The Horsehead Nebula (2009-07-21)

One of the most identifiable nebulae in the sky, the Horsehead Nebula in Orion, is part of a large, dark, molecular cloud.  Also known as Barnard 33, the unusual shape was first discovered on a photographic plate in the late 1800s.  The red glow originates from hydrogen gas predominantly behind the nebula, ionized by the nearby bright star Sigma Orionis.  The darkness of the Horsehead is caused mostly by thick dust, although the lower part of the Horsehead's neck casts a shadow to the left.  Streams of gas leaving the nebula are funneled by a strong magnetic field.  Bright spots in the Horsehead Nebula's base are young stars just in the process of forming.  Light takes about 1,500 years to reach us from the Horsehead Nebula.  The above image was taken with the 0.9-meter telescope at Kitt Peak National Observatory.

Image credit: Nigel Sharp
The Lagoon Nebula in Gas, Dust, and Stars (2009-07-22)

Stars are battling gas and dust in the Lagoon Nebula but the photographers are winning. Also known as M8, this photogenic nebula is visible even without binoculars towards the constellation of Sagittarius. The energetic processes of star formation create not only the colors but the chaos. The red-glowing gas, shown on the above left in re-assigned colors,  results from high-energy starlight striking interstellar hydrogen gas. The Trifid nebula is visible on the far right.  The dark dust filaments that lace M8 were created in the atmospheres of cool giant stars and in the debris from supernovae explosions. The light from M8 we see today left about 5,000 years ago. Light takes about 50 years to cross this section of M8.

Image credit: Florencio Rodil
Jupiter's New Impact Scar (2009-07-23)

In July of 1994 pieces of Comet Shoemaker-Levy 9 collided with planet Jupiter. The explosive impacts sent plumes of debris high into the Jovian atmosphere creating dark markings or scars, visible for a time against the cloud bands. Remarkably, 15 years later, another impact scar was discovered in the Jovian atmosphere by amateur astronomer Anthony Wesley as he examined images of the gas giant taken from his home observatory just outside Murrumbateman NSW Australia. Jupiter's south pole is at the top in this July 19 discovery image, with Jupiter rotating from right to left. The dark marking, also likely caused by a comet or asteroid impact, is near the top of the view, left of a pre-existing, whitish, oval-shaped storm. NASA's Infrared Telescope Facility images from Mauna Kea, Hawaii later confirmed the likely impact site's dark scar and plume of particles in Jupiter's upper atmosphere. Since 2006, major discovery observations by amateur astronomers have also included two red spots on Jupiter.

Image credit: Anthony Wesley
Eclipse over Chongqing, China (2009-07-24)

The daytime sky grew dark, the temperature dropped, and lights came on as Chongqing, China, was plunged into the Moon's shadow during the July 22nd total solar eclipse. This serene, wide-angle view of the event looks to the east over the large, populous city from a newly constructed park. Despite thin clouds, it captures the shimmering solar corona just before the end of the eclipse total phase. This total solar eclipse occurred near Aphelion, the point in Earth's elliptical orbit farthest from the Sun, and so the Sun was near its smallest apparent size. It also occurred when the New Moon was near Perigee, the closest point to Earth in the Moon's elliptical orbit, making the Moon near its largest apparent size. The small Sun and large Moon made this the longest solar eclipse of this century.

Image credit: Stephan Heinsius
The Eagle Rises (2009-07-25)

Get out your red/blue glasses and check out this remarkable stereo view from lunar orbit. Created from two photographs (AS11-44-6633, AS11-44-6634) taken by astronaut Michael Collins forty years ago during the 1969 Apollo 11 mission, the 3D anaglyph features the lunar module ascent stage, dubbed The Eagle, as it rises to meet the command module in lunar orbit. Aboard the ascent stage are Neil Armstrong and Buzz Aldrin, the first to walk on the Moon. The smooth, dark area on the lunar surface is Mare Smythii located just below the equator on the extreme eastern edge of the Moon's near side.  Poised beyond the lunar horizon, is our fair planet Earth.

Image credit: ALSJ
The Big Corona (2009-07-26)

Most photographs don't adequately portray the magnificence of the Sun's corona. Seeing the corona first-hand during a total solar eclipse is best.  The human eye can adapt to see features and extent that photographic film usually cannot.  Welcome, however, to the digital age.  The above picture is a combination of thirty-three photographs that were digitally processed to highlight faint features of a total eclipse that occurred in March of 2006.  The images of the Sun's corona were digitally altered to enhance dim, outlying waves and filaments.  Shadow seekers need not fret, though, since as yet there is no way that digital image processing can mimic the fun involved in experiencing a total solar eclipse. Last week, a spectacular total solar eclipse occurred over southern Asia, while the The next total solar eclipse will be visible from the South Pacific on 2010 July 11.    Note: An APOD editor will review great space images this Saturday night at Ft. Wilkins, Michigan.

Image credit: Koen van Gorp
NGC 1097: Spiral Galaxy with a Central Eye (2009-07-27)

What's happening at the center of spiral galaxy NGC 1097?  No one is sure, but it likely involves a supermassive black hole. Matter falling in from a bar of stars and gas across the center is likely being heated by an extremely energetic region surrounding the central black hole.  From afar, the entire central region appears in the above false-color infrared image as a mysterious eye. Near the left edge and seen in blue, a smaller companion galaxy is wrapped in the spectacular spiral arms of the large spiral, lit in pink by glowing dust. Currently about 40 thousand light-years from the larger galaxy's center, the gravity of the companion galaxy appears to be reshaping the larger galaxy as it is slowly being destroyed itself. NGC 1097 is located about 50 million light years away toward the constellation of the furnace (Fornax).    Note: An APOD editor will review great space images this Saturday night at Ft. Wilkins, Michigan.
A Floral Aurora Corona (2009-07-28)

Few auroras show this level of detail. Above, a standard digital camera captured a particularly active and colorful auroral corona that occurred last week above Alberta, Canada. With a shape reminiscent of a flower, the spectacular aurora had an unusually high degree of detail. The vivid green and purple  auroral colors are caused by high atmospheric oxygen and hydrogen reacting to a burst of incoming electrons.  Many photogenic auroras have been triggered from a solar wind stream that recently passed the Earth. The auroras were unexpected because the initiating Sun has been unusually quiet of late.    Note: An APOD editor will review great space images this Saturday night at Ft. Wilkins, Michigan.

Image credit: Zoltan Kenwell
(Infocus Imagery)
The Milky Way Over Devils Tower (2009-07-29)

Was Devils Tower once an explosive volcano? Famous for its appearance in films such as Close Encounters, the origin of Devil's Tower in Wyoming, USA is still debated, with a leading hypothesis holding that it is a hardened lava plume that probably never reached the surface to become a volcano.  The lighter rock that once surrounded the dense volcanic neck has now eroded away, leaving the dramatic tower. High above, the central band of the Milky Way galaxy arches across the sky. Many notable sky objects are visible, including dark strands of the Pipe Nebula and the reddish Lagoon Nebula to the tower's right. Green grass and trees line the moonlit foreground, while clouds appear near the horizon to the tower's left. Unlike many other international landmarks, mountaineers are permitted to climb Devils Tower.    Note: An APOD editor will review great space images this Saturday night at Ft. Wilkins, Michigan.

Image credit: Wally Pacholka
6 Minutes 42 Seconds (2009-07-30)

The July 22nd total solar eclipse was the longest of the 21st century. From the point of maximum eclipse along the Moon's shadow track across the Pacific Ocean, the Moon completely blocked the Sun for a total of 6 minutes and 39 seconds. But from the deck of this cruise ship the duration of the total eclipse phase was extended to a whopping 6 minutes and 42 seconds by the ship's motion along the shadow track. This panoramic view of the scene shows the shimmering solar corona in a darkened daytime sky, with clouds silhouetted by a bright sky on the distant horizon, beyond the Moon's shadow. Mercury can be seen near the eclipsed Sun. Venus lies near the upper right edge of the frame.

Image credit: Babak
Tafreshi
Hubble View: Jupiter Impact (2009-07-31)

This sprawling dark marking is Jupiter's latest impact scar, a debris plume created as a small asteroid or comet disintegrated after plunging into the gas giant's atmosphere. Located in Jupiter's south polar region, the new feature was discovered by Australian amateur astronomer Anthony Wesley on July 19. On July 23rd Wesley's discovery was followed up by the Hubble Space Telescope with its newly installed Wide Field Camera 3, creating this sharpest view of the evolving debris plume. Estimates indicate that the impacting object itself was several hundred meters across. Similar impact markings were created when pieces of Comet Shoemaker-Levy 9 slammed into Jupiter's cloud bands in July of 1994.
SN 1006 Supernova Remnant (2009-08-01)

A new star, likely the brightest supernova in recorded human history, lit up planet Earth's sky in the year 1006 AD. The expanding debris cloud from the stellar explosion, found in the southerly constellation of Lupus, still puts on a cosmic light show across the electromagnetic spectrum. In fact, this composite view includes X-ray data in blue from the Chandra Observatory, optical data in yellowish hues, and radio image data in red. Now known as the SN 1006 supernova remnant, the debris cloud appears to be about 60 light-years across and is understood to represent the remains of a white dwarf star. Part of a binary star system, the compact white dwarf gradually captured material from its companion star. The buildup in mass finally triggered a thermonuclear explosion that destroyed the dwarf star. Because the distance to the supernova remnant is about 7,000 light-years, that explosion actually happened 7,000 years before the light reached Earth in 1006. Shockwaves in the remnant accelerate particles to extreme energies and are thought to be a source of the mysterious cosmic rays.
Stars, Dust and Nebula in NGC 6559 (2009-08-02)

When stars form, pandemonium reigns.  A textbook case is the star forming region NGC 6559.  Visible above are red glowing emission nebulas of hydrogen, blue reflection nebulas of dust, dark absorption nebulas of dust, and the stars that formed from them.  The first massive stars formed from the dense gas will emit energetic light and winds that erode, fragment, and sculpt their birthplace.  And then they explode. The resulting morass can be as beautiful as it is complex.  After tens of millions of years, the dust boils away, the gas gets swept away, and all that is left is a naked open cluster of stars.

Image credit: Adam Block
T Tauri: A Star is Formed (2009-08-03)

What does a star look like when it is forming?  The prototypical example is the variable star T Tauri, visible as the bright orange star near the image center. The orange star centered in this remarkable telescopic skyview is T Tauri, prototype of the class of T Tauri variable stars. Surrounding T Tauri is a dusty yellow cosmic cloud named the Hind's Variable Nebula (NGC 1555/1554). Over 400 light-years away, at the edge of a molecular cloud, both star and nebula are seen to vary significantly in brightness but not necessarily at the same time, adding to the mystery of the intriguing region. T Tauri stars are now generally recognized as young -- less than a few million years old -- sun-like stars still in the early stages of formation. To further complicate the picture, infrared observations indicate that T Tauri itself is part of a multiple star system. Surprisingly, due to a close gravitational pass near one of these stars, T Tauri may now be headed out of the system.  The dramatic color image above captures a region that spans about 4 light-years.

Image credit: T. Rector
A Triple Sunrise Over Gdansk Bay (2009-08-04)

How can the same Sun rise three times? Last month on Friday, 2009 July 10, a spectacular triple sunrise was photographed at about 4:30 am over Gdansk Bay in Gdansk, Poland.  Clearly, our Sun rises only once. Some optical effect is creating at least two mirages of the Sun -- but which effect? In the vast majority of similarly reported cases, mirages of the brightest object in the frame can be traced to reflections internal to the camera taking the images. Still, the above image is intriguing because a sincere photographer claims the effect was visible to the unaided eye, and because the photographer took several other frames that show variants of the same effect.  Therefore, polite readers are invited to debate whether the above image captures a particularly spectacular example of common reflections inside a standard digital camera, shows one of the most spectacular examples of atmospheric lensing yet recorded, or was caused by something completely different. If the discussion converges, the consensus will be posted here at a later date.

Image credit: Barry & Noemi Diacon
(McMaster U.)
Betelgeuse Resolved (2009-08-05)

The sharpest image ever of Betelgeuse shows a mammoth star that is slowly evaporating. Betelgeuse (sounds a lot like "beetle juice"), also known as Alpha Orionis, is one of the largest and brightest stars known. The star is a familiar orange fixture easily visible to the unaided eye toward the constellation of Orion.  This recent image from the Very Large Telescope in Chile resolves not only the face of Betelgeuse, but a large and previously unknown plume of surrounding gas. This plume gives fresh indications of how the massive star is shedding mass as it nears the end of its life. Conversely, a series of previous observations indicate that the surface of Betelgeuse has noticeably shrunk, on the average, over the past decade. If Betelgeuse, a red supergiant star about 640 light years distant, were placed at the center of our Solar System, the plume would extend past the orbit of Jupiter. Since Betelgeuse is known to change its brightness irregularly, future observations may determine if changes its appearance irregularly as well. Betelgeuse is a candidate to undergo a spectacular supernova explosion almost anytime in the next few thousand years.
Galaxies in Pegasus (2009-08-06)

This wide, sharp telescopic view reveals galaxies scattered beyond the stars at the northern boundary of the high-flying constellation Pegasus. Prominent at the upper right is NGC 7331. A mere 50 million light-years away, the large spiral is one of the brighter galaxies not included in Charles Messier's famous 18th century catalog. The disturbed looking group of galaxies at the lower left is well-known as Stephan's Quintet. About 300 million light-years distant, the quintet dramatically illustrates a multiple galaxy collision, its powerful, ongoing interactions posed for a brief cosmic snapshot. On the sky, the quintet and NGC 7331 are separated by about half a degree.

Image credit: Dietmar Hager
The Star Clusters of NGC 1313 (2009-08-07)

Like grains of sand on a cosmic beach, individual stars of barred spiral galaxy NGC 1313 are resolved in this sharp composite from the Hubble Space Telescope's Advanced Camera for Surveys (ACS). The inner region of the galaxy is pictured, spanning about 10,000 light-years. Hubble's unique ability to distinguish individual stars in the 14 million light-year distant galaxy has been used to unravel the fate of star clusters whose bright young stars are spread through the disk of the galaxy as the clusters dissolve. The exploration of stars and clusters in external galaxy NGC 1313 offers clues to star formation and star cluster evolution in our own Milky Way.
Diamonds in a Cloudy Sky (2009-08-08)

Cloudy skies over Wuhan, China hid the delicate solar corona during July's total eclipse of the Sun. Still, the Moon's silhouette was highlighted by these glistening diamonds as the total eclipse phase ended. Caused by bright sunlight streaming through dips and valleys in the irregular terrain along the Moon's edge, the effect is known as Baily's Beads, named after Francis Baily who called attention to the phenomenon in 1836. The dramatic appearance of the beads at the beginning or end of a total solar eclipse is also known as the Diamond Ring effect. In this remarkable image, a small, pinkish solar prominence can also be seen along the edge, below the diamonds.

Image credit: OSAE
Saturn's Iapetus: Painted Moon (2009-08-09)

What has happened to Saturn's moon Iapetus?  Vast sections of this strange world are dark as coal, while others are as bright as ice.  The composition of the dark material is unknown, but infrared spectra indicate that it possibly contains some dark form of carbon.  Iapetus also has an unusual equatorial ridge that makes it appear like a walnut.  To help better understand this seemingly painted moon, NASA directed the robotic Cassini spacecraft orbiting Saturn to swoop within 2,000 kilometers in 2007. Pictured above, from about 75,000 kilometers out, Cassini's trajectory allowed unprecedented imaging of the hemisphere of Iapetus that is always trailing.  A huge impact crater seen in the south spans a tremendous 450 kilometers and appears superposed on an older crater of similar size. The dark material is seen increasingly coating the easternmost part of Iapetus, darkening craters and highlands alike.  Close inspection indicates that the dark coating typically faces the moon's equator and is less than a meter thick. A leading hypothesis is that the dark material is mostly dirt leftover when relatively warm but dirty ice sublimates. An initial coating of dark material may have been effectively painted on by the accretion of meteor-liberated debris from other moons. This and other images from Cassini's Iapetus flyby are being studied for even greater clues.
Moonbow and Rainbows Over Patagonia (2009-08-10)

Have you ever seen a moonbow?  Just as rainbows are lit by the Sun, moonbows are lit by the Moon.  Since the Sun is so much brighter than the Moon, sunlit rainbows are much brighter and more commonly seen than moonbows.  The above movie captures not only a moonbow, but several rainbows, moving clouds, and the starry sky visible in 2009 February over Patagonia in Chile. The slight movement of the rainbows is due to the changing sky position of the Sun. Since moonlight is itself reflected sunlight, the colors are nearly the same. Both rainbows and moonbows are created by light being scattered inside small water droplets, typically from a nearby rainfall.  The raindrops each act as miniature prisms, together creating the picturesque spectrum of colors seen.

Image credit: Stéphane Guisard
Inside Barringer Meteor Crater (2009-08-11)

What happens when a meteor hits the ground?  Usually nothing much, as most meteors are small, and indentations they make are soon eroded away.  About 50,000 years ago, however, a large meteor created Barringer Meteor Crater in Arizona, USA. Also known simply as Meteor Crater, the resulting impact basin spans over a kilometer.  Pictured above, a tour group views the inside of Barringer Crater early last year. Historically, Barringer Crater was the first feature on Earth to be recognized as an impact crater.  Today, over 100 terrestrial impact features have been identified on planet Earth.  Computer modeling indicates that some of the Canyon Diablo impactor melted during the impact that created Barringer.

Image credit: Tony Rowell
Irregular Galaxy NGC 55 (2009-08-12)

Irregular galaxy NGC 55 is thought to be similar to the Large Magellanic Cloud (LMC). But while the LMC is about 180,000 light-years away and is a well known satellite of our own Milky Way Galaxy, NGC 55 is more like 6 million light-years distant and is a member of the Sculptor Galaxy Group. Classified as an irregular galaxy, in deep exposures the LMC itself resembles a barred disk galaxy. However, spanning about 50,000 light-years, NGC 55 is seen nearly edge-on, presenting a flattened, narrow profile in contrast with our face-on view of the LMC. Just as large star forming regions create emission nebulae in the LMC, NGC 55 is also seen to be producing new stars. This highly detailed galaxy portrait highlights a bright core crossed with dust clouds, telltale pinkish star forming regions, and young blue star clusters in NGC 55.

Image credit: Don Goldman
Block Island Meteorite on Mars (2009-08-13)

What is this strange rock on Mars? Sitting on a smooth plane, the rock stands out for its isolation, odd shape, large size and unusual texture. The rock was discovered by the robotic Opportunity rover rolling across Mars late last month.  Pictured, Opportunity prepares to inspect the unusual rock. After being X-rayed, poked, and chemically analyzed, the rock has now been identified by Opportunity as a fallen meteorite. Now dubbed Block Island, the meteorite has been measured to be about 2/3 of a meter across and is now known to be composed mostly of nickel and iron.  This is the second meteorite found by a martian rover, and so far the largest.  Vast smooth spaces on Mars and Earth can make large meteorites stand out. Opportunity continues its trip across Meridiani Planum on Mars and is on schedule to reach expansive Endeavour Crater next year.
Shuttle and Meteor (2009-08-14)

This early morning skyscape was captured last week on August 4th, looking northeast across calm waters in the Turn Basin at NASA's Kennedy Space Center. In a striking contrast in motion, the space shuttle Discovery, mounted on a massive transporter, creeps toward launch pad 39A at less than two miles per hour, while a brilliant meteor streaks through the sky traveling many miles per second. Of course, this week skywatchers have seen many similar meteor streaks during the annual Perseid meteor shower. But the meteor flashing above Discovery is not likely to be one of the Perseids because its path doesn't point back to that shower's radiant. Seen here near picture center, brilliant planet Venus still dominates the sky as the Morning Star, though. Yellowish tinted Mars lies near the top of the frame and Orion's red giant star Betelgeuse is toward the right.

Image credit: Spaceflightnow.com