omnianasa/nasa-apod-metadata huggingface dataset:
Southern Comet (2007-01-18)
After a remarkable performance in the northern hemisphere, the brightest comet in decades is now showing off in the south. Recorded during evening twilight on January 17, this view features the bright coma and gorgeous, sweeping tail of Comet McNaught (c/2006 P1) over Lake Horowhenua in Levin, a small town on New Zealand's North Island. Astronomer Noel Munford reports that the five second long digital camera exposure comes close to capturing the visual appearance of the comet in a sky coloured by smoke from distant brush fires in Australia. Discovered last summer by R. H. McNaught (Siding Spring Survey), the comet grew impressively bright in early January and has even been sighted in full daylight. In the coming days Comet McNaught will continue to move south, for now a spectacle in southern skies as it heads for the outer solar system.
McNaught's Matinee (2007-01-19)
Comets grow bright when they're close to the Sun, basking in the intense solar radiation. Of course, they're also usually impossible to see against the overwhelming scattered sunlight. But surprising Comet McNaught - whose January 12 closest approach to the Sun (perihelion passage) was well inside the orbit of Mercury - gave an enjoyable performance in bright blue daytime skies. In fact, comet expert David Levy captured this remarkable inset (upper left) telescopic view of McNaught within an hour of perihelion, with the comet in broad daylight only about 7 degrees away from the Sun's position. Stefan Seip's wider daytime view of the comet and fluffy clouds was recorded approximately a day later. Seip used a polarizing filter and a telescope/camera set up near Stuttgart, Germany. No longer visible in broad daylight, Comet McNaught is now touring twilight southern skies.
SOHO: Comet McNaught Movie (2007-01-20)
This frame from a spectacular time lapse movie shows Comet McNaught - the Great Comet of 2007 - sweeping through the inner solar system. The movie frames were recorded from January 12 through Jan 16 by a coronograph onboard the sun-staring SOHO spacecraft. Bright planet Mercury also glides dramatically through the field of view but the Sun itself remains fixed, hidden behind the coronograph's central occulting disk. The broad-tailed comet is so bright it almost overwhelms SOHO's sensitive camera designed to explore the fainter structures in the Sun's outer atmosphere. Comet McNaught's closest approach to the Sun (perihelion on January 12) was only 0.17 astronomical units, or about half the distance between the Sun and Mercury. (Note: To download the movie file, click on the picture.)
The Sombrero Galaxy in Infrared (2007-01-21)
This floating ring is the size of a galaxy.  In fact, it is part of the photogenic Sombrero Galaxy, one of the largest galaxies in the nearby Virgo Cluster of Galaxies.  The dark band of dust that obscures the mid-section of the Sombrero Galaxy in optical light actually glows brightly in infrared light.  The above image shows the infrared glow, recently recorded by the orbiting Spitzer Space Telescope, superposed in false-color on an existing image taken by NASA's Hubble Space Telescope in optical light.  The Sombrero Galaxy, also known as M104, spans about 50,000 light years across and lies 28 million light years away.  M104 can be seen with a small telescope in the direction of the constellation Virgo.
The Magnificent Tail of Comet McNaught (2007-01-22)
Comet McNaught, the Great Comet of 2007, has grown a long and filamentary tail.  The spectacular tail spreads across the sky and is visible to Southern Hemisphere observers just after sunset.  The head of the comet remains quite bright and easily visible to even city observers without any optical aide.  The amazing tail is visible on long exposures and even to the unaided eye from a dark location.  Reports even have the tail visible just above the horizon after sunset for many northern observers as well.  Comet McNaught, estimated at magnitude -2 (minus two), was caught by the comet's discoverer in the above image just after sunset last Friday from Siding Spring Observatory in Australia. Comet McNaught, the brightest comet in decades, is now fading as it moves further into southern skies and away from the Sun and Earth.
The Milky Way Over Paranal (2007-01-23)
It's not the sky that's falling. More accurately, the Earth is rising.   The Earth's rotation gives a continually changing view to all Earth observers, including those measuring the universe at the Paranal Observatory. The observatory's four, massive 8.2 meter telescope units are situated on top of the 2,600 meter high mountain, Cerro Paranal, in the dry Atacama Desert in northern Chile. The individual unit telescopes can be used separately or in combination. Their names, Antu, Kueyen, Melipal, and Yepun, are taken from the Mapuche language. Fittingly they translate to Sun, Moon, Evening Star, and Southern Cross. Together they are fittingly known as the European Southern Observatory's Very Large Telescope. A higher time resolution version of the above movie is available here.
A Comet Tail Horizon (2007-01-24)
What's happening over the horizon?  Many a sky enthusiast who thought they had seen it all had never seen anything like this.  To the surprise of many Northern Hemisphere observers, the tail of Comet McNaught remained visible even after the comet's head set ahead of the Sun.  What's more, visible were bright but extremely rare filamentary striae from the comet's expansive dust tail.  The cause of dust tail striae are not known for sure, but are possibly related to fragmentation of comet's nucleus. The last comet to show prominent striae was Comet Hale-Bopp in 1997. Pictured above, the tail of Comet McNaught was caught just after sunset last Friday above the Carnic Alps of northern Italy.
Orion's Cradle (2007-01-25)
Cradled in glowing hydrogen, stellar nurseries in Orion lie at the edge of a giant molecular cloud some 1,500 light-years away. This breath-taking view spans about 13 degrees across the center of the well-known constellation with the Great Orion Nebula, the closest large star forming region, just right of center. The deep mosaic also includes (left of center), the Horsehead Nebula, the Flame Nebula, and Orion's belt stars. Image data acquired with a hydrogen alpha filter adds other remarkable features to this wide angle cosmic vista -- pervasive tendrils of energized atomic hydrogen gas and portions of the surrounding Barnard's Loop. While the Orion Nebula and belt stars are easy to see with the unaided eye, emission from the extensive interstellar gas is faint and much harder to record, even in telescopic views of the nebula-rich complex.
The Star Clusters of NGC 1313 (2007-01-26)
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.
Castle and Sky (2007-01-27)
While Comet McNaught ruled southern skies, last week's conjunction of the Moon and Venus could be enjoyed by denizens of both hemispheres of planet Earth. The two more commonly viewed celestial beacons produced this lovely twilight scene, recorded last Saturday in skies above Almodovar near Cordoba in southern Spain. Brilliant Venus and a slender crescent Moon seem to overlook the small town, along with a well-lit Castle Almodovar. The impressive castle's construction began in the 700s on the strategic site of a Roman fort. It was extensively restored in the 20th century.
Saturn's Hyperion: A Moon with Odd Craters (2007-01-28)
What lies at the bottom of Hyperion's strange craters?  Nobody knows. To help find out, the robot Cassini spacecraft now orbiting Saturn swooped past the sponge-textured moon in late 2005 and took an image of unprecedented detail.  That image, shown above in false color, shows a remarkable world strewn with strange craters and a generally odd surface.   The slight differences in color likely show differences in surface composition.   At the bottom of most craters lies some type of unknown dark material.  Inspection of the image shows bright features indicating that the dark material might be only tens of meters thick in some places.   Hyperion is about 250 kilometers across, rotates chaotically, and has a density so low that it might house a vast system of caverns inside.
Movie: A Green Flash Over Italy (2007-01-29)
How could the Sun turn green?  Difficult to observe, the momentary green flash above the rising or setting sun has been documented as a phenomenon caused by the atmospheric bending or refraction of sunlight. Like a weak prism, the Earth's atmosphere breaks white sunlight into colors, bending red colors slightly and green and blue colors through increasingly larger angles. When the sky is clear, a green flash just above the sun's edge can sometimes be seen for a second or so, when the sun is close to a distant horizon. Still, from a site atop Mt. Autore (altitude 1,850 meters) in Italy astrophotographer Danilo Pivato captured this dramatic green flash movie.  The time between frames varies from over one minute in the beginning to about one second as the flash becomes visible.
Thor's Helmet from CFHT (2007-01-30)
NGC 2359 is a striking emission nebula with an impressive popular name - Thor's Helmet Sure, its suggestive winged appearance might lead some to refer to it as the "duck nebula", but if you were a nebula which name would you choose? By any name NGC 2359 is a bubble-like nebula some 30 light-years across, blown by energetic winds from an extremely hot star seen near the center and classified as a Wolf-Rayet star. Wolf-Rayet stars are rare massive blue giants which develop stellar winds with speeds of millions of kilometers per hour. Interactions with a nearby large molecular cloud are thought to have contributed to this nebula's more complex shape and curved bow-shock structures. NGC 2359 is about 15,000 light-years distant toward the constellation Canis Major.
Movie: Cassini Crosses Saturn's Ring Plane (2007-01-31)
What would the rings of Saturn look like if you passed right through the ring plane? To find out, NASA aimed cameras from the Cassini spacecraft right at Saturn's rings as the robotic explorer passed from the sunlit side of the rings to the shadowed side.   Resulting images from a vantage point outside the rings and most moons, but inside the orbit of Titan, have been gathered together in the above time-lapse movie.  The dramatic movie demonstrates that ring particle density and reflectivity makes some parts of the shadowed side nearly the photographic negative of the sunlit side, but nearly empty regions remain continually dark.  Visible also are Saturn-orbiting moons Enceladus, Mimas, Janus, Epimetheus, Prometheus, and Pandora.  The extreme thinness of Saturn's rings can be appreciated from frames taken near the crossing time.
A Tail of Two Hemispheres (2007-02-01)
By January 19/20 Comet McNaught's magnificent dust tail stretched for about 150 million kilometers (~1 AU), requiring images from both southern and northern hemispheres of planet Earth to take it all in. Two such views - from Cerro Paranal in Chile (left) and the Carnic Alps in Italy - are combined in this unique graphic that also outlines a perspective view of the comet's orbit (dotted line) and relative position of the Sun. Driven by solar radiation pressure the dust tail initially points away from the Sun, but also trails outside the comet's orbit. Astronomers try to account for the complex structure along the tail, including the pronounced striations, by considering forces acting on the dust (e.g. gravity, solar wind and radiation) as well as the release time and size of the dust grains. In the diagram, the modeled location of dust grains released at approximately the same time relative to perihelion passage, synchrones, are shown as dashed lines. The location of grains of similar size, syndynes, are shown as solid lines.
Flame Nebula Close-Up (2007-02-02)
Of course, the Flame Nebula is not on fire. Also known as NGC 2024, the nebula's suggestive reddish color is due to the glow of hydrogen atoms at the edge of the giant Orion molecular cloud complex some 1,500 light-years away. The hydrogen atoms have been ionized, or stripped of their electrons, and glow as the atoms and electrons recombine.  But what ionizes the hydrogen atoms? In this close-up view, a dark lane of absorbing interstellar dust stands out in silhouette against the hydrogen glow and actually hides the true source of the Flame Nebula's energy from optical telescopes. Behind the dark lane lies a cluster of hot, young stars, seen at infrared wavelengths through the obscuring dust.  A young, massive star in that cluster is the likely source of energetic ultraviolet radiation that ionizes the hydrogen gas in the Flame Nebula.
Alborz Mountains in Moonlight (2007-02-03)
On January 25th, light from a first quarter Moon illuminated this dreamlike landscape looking across the rugged, snow-covered peaks of the Alborz Mountain Range in northern Iran. The stunning sky is filled with stars, including the yellow-tinged Betelgeuse at the shoulder of Orion. Sirius, alpha star of Canis Major and the brightest star in planet Earth's night, stands above and left of picture center. The eerie glow along the Haraz valley in the foreground is light from cars traveling a highway leading from Tehran to the Caspian Sea.
Shadow of a Martian Robot (2007-02-04)
What if you saw your shadow on Mars and it wasn't human?  Then you might be the Opportunity rover currently exploring Mars.  Opportunity and sister robot Spirit have been probing the red planet since early 2004, finding evidence of ancient water, and sending breathtaking images across the inner Solar System.  Pictured above, Opportunity looks opposite the Sun into Endurance Crater and sees its own shadow.  Two wheels are visible on the lower left and right, while the floor and walls of the unusual crater are visible in the background.  Opportunity and Spirit have now spent over three years exploring the red world, find new clues into the wet ancient past of our Solar System's second most habitable planet.
Comet Between Fireworks and Lightning (2007-02-05)
Sometimes the sky itself is the best show in town.  On January 26, people from Perth, Australia gathered on a local beach to watch a sky light up with delights near and far.  Nearby, fireworks exploded as part of Australia Day celebrations.  On the far right, lightning from a thunderstorm flashed in the distance.  Near the image center, though, seen through clouds, was the most unusual sight of all: Comet McNaught.  The photogenic comet was so bright that it even remained visible though the din of Earthly flashes.  Comet McNaught continues to move out from the Sun and dim, but should remain visible in southern skies with binoculars through the end of this month. The above image is actually a three photograph panorama digitally processed to reduce red reflections from the exploding firework.
Sun Storm: A Coronal Mass Ejection (2007-02-06)
What's happening to our Sun?  Another Coronal Mass Ejection (CME)!  The Sun-orbiting SOHO spacecraft has imaged many erupting filaments lifting off the active solar surface and blasting enormous bubbles of magnetic plasma into space. Direct light from the sun is blocked in the inner part of the above image, taken in 2002, and replaced by a simultaneous image of the Sun in ultraviolet light.  The field of view extends over two million kilometers from the solar surface. While hints of these explosive events, called coronal mass ejections or CMEs, were discovered by spacecraft in the early 70s, this dramatic image is part of a detailed record of this CME's development from the presently operating SOHO spacecraft.  Near the minimum of the solar activity cycle CMEs occur about once a week, but near solar maximum rates of two or more per day are typical. Strong CMEs may profoundly influence space weather. Those directed toward our planet can have serious effects.
Liquid Lakes on Saturn's Titan (2007-02-07)
Why would some regions on Titan reflect very little radar?   The leading explanation is that these regions are lakes, possibly composed of liquid methane.  The above image is a false-color synthetic radar map of a northern region of Titan taken during a flyby of the cloudy moon by the robotic Cassini spacecraft last July.  On this map, which spans about 150 kilometers across, dark regions reflect relatively little of the broadcast radar signal.  Images like this show Titan to be only the second body in the Solar System to possess liquids on the surface.  Future observations from Cassini during Titan flybys will further test the methane lake hypothesis, as comparative wind effects on the regions are studied.
Galaxies Away (2007-02-08)
This stunning group of galaxies is far, far away - about 450 million light-years from planet Earth - cataloged as galaxy cluster Abell S0740. Dominated by the cluster's large central elliptical galaxy (ESO 325-G004), this sharp Hubble view takes in a remarkable assortment of galaxy shapes and sizes with only a few spiky foreground stars scattered through the field. The giant elliptical galaxy spans over 100,000 light years and contains about 100 billion stars, comparable in size to our own spiral Milky Way. The Hubble data reveal a wealth of detail in even these distant galaxies, including magnificent arms and dust lanes, star clusters, ring structures, and gravitational lensing arcs.
Ptolemaeus, Alphonsus and Arzachel (2007-02-09)
These three ancient, large impact craters lie on the north eastern shores of Mare Nubium, the lunar Sea of Clouds. Along the top of the stark mosaic (left to right) are the namesakes of Ptolemaeus, Alphonsus and Arzachel. The picture offers a remarkably detailed view of the well-studied region with shadows emphasizing the large crater central peaks and slumping walls. Careful examination also reveals the 110 kilometer long Straight Wall, a fault 200-300 meters high, and the intriguing Davy crater chain. Overall, the striking moonscape is similar to the final images recorded by the Ranger 9 spacecraft, before it crashed into the 108 kilometer wide crater Alphonsus in March of 1965.
Stars of the Galactic Center (2007-02-10)
The center of our Milky Way Galaxy is hidden from the prying eyes of optical telescopes by clouds of obscuring dust and gas. But in this stunning vista, the Spitzer Space Telescope's infrared cameras, penetrate much of the dust revealing the stars of the crowded galactic center region. A mosaic of many smaller snapshots, the detailed, false-color image shows older, cool stars in bluish hues. Reddish glowing dust clouds are associated with young, hot stars in stellar nurseries. The galactic center lies some 26,000 light-years away, toward the constellation Sagittarius. At that distance, this picture spans about 900 light-years.
Io: The Prometheus Plume (2007-02-11)
What's happening on Jupiter's moon Io? Two sulfurous eruptions are visible on Jupiter's volcanic moon Io in this color composite image from the robotic Galileo spacecraft that orbited Jupiter from 1995 to 2003. At the image top, over Io's limb, a bluish plume rises about 140 kilometers above the surface of a volcanic caldera known as Pillan Patera. In the image middle, near the night/day shadow line, the ring shaped Prometheus plume is seen rising about 75 kilometers above Io while casting a shadow below the volcanic vent. Named for the Greek god who gave mortals fire, the Prometheus plume is visible in every image ever made of the region dating back to the Voyager flybys of 1979 - presenting the possibility that this plume has been continuously active for at least 18 years. The above digitally sharpened image was originally recorded in 1997 on June 28 from a distance of about 600,000 kilometers.
Comet McNaught Over New Zealand (2007-02-12)
Comet McNaught is perhaps the most photogenic comet of our time.  After making quite a show in the northern hemisphere in mid January, the comet moved south and developed a long and unusual dust tail that dazzled southern hemisphere observers starting in late January. Comet McNaught was imaged two weeks ago between Mount Remarkable and Cecil Peak in this spectacular image taken from Queenstown, South Island, New Zealand.   The bright comet dominates the right part of the above image, while the central band of our Milky Way Galaxy dominates the left.  Careful inspection of the image will reveal a meteor streak just to the left of the comet.  Comet McNaught continues to move out from the Sun and dim, but should remain visible in southern skies with binoculars through the end of this month.
Vela Supernova Remnant in Visible Light (2007-02-13)
The explosion is over but the consequences continue.  About eleven thousand years ago a star in the constellation of Vela could be seen to explode, creating a strange point of light briefly visible to humans living near the beginning of recorded history.  The outer layers of the star crashed into the interstellar medium, driving a shock wave that is still visible today.  A roughly spherical, expanding shock wave is visible in X-rays. The above image captures much of that filamentary and gigantic shock in visible light, spanning almost 100 light years and appearing twenty times the diameter of the full moon. As gas flies away from the detonated star, it decays and reacts with the interstellar medium, producing light in many different colors and energy bands. Remaining at the center of the Vela Supernova Remnant is a pulsar, a star as dense as nuclear matter that completely rotates more than ten times in a single second.
The Rosette Nebula (2007-02-14)
Would the Rosette Nebula by any other name look as sweet?  The bland New General Catalog designation of NGC 2237 doesn't appear to diminish the appearance of the  this flowery emission nebula.  Inside the nebula lies an open cluster of bright young stars designated NGC 2244.  These stars formed about four million years ago from the nebular material and their  stellar winds are clearing a hole in the nebula's center, insulated by a layer of dust and hot gas.  Ultraviolet light from the hot cluster stars causes the surrounding nebula to glow. The Rosette Nebula spans about 100 light-years across, lies about 5000 light-years away, and can be seen with a small telescope towards the constellation of Monoceros.
Planetary Nebula NGC 2440 (2007-02-15)
Planetary nebula NGC 2440 has an intriguing bow-tie shape in this stunning view from space. The nebula is composed of material cast off by a dying sun-like star as it enters its white dwarf phase of evolution. Details of remarkably complex structures are revealed within NGC 2440, including dense ridges of material swept back from the nebula's central star. Near the center of the view, the star itself is one of the hottest known, with a surface temperature of about 200,000 kelvins. About 4,000 light-years from planet Earth toward the nautical constellation Puppis, the nebula spans over a light-year and is energized by ultraviolet light from the central star. The false-color image was recorded earlier this month using the Hubble's Wide-Field Planetary Camera 2(WFPC2), demonstrating still impressive imaging capabilities following the failure of the Advanced Camera for Surveys.