juliensimon/nasa-apod huggingface dataset:
The Trail of a Minotaur (2013-11-21)

Star trails arc above a moonlit beach and jetty in this serene sea and night skyscape. Captured on November 19, the single time exposure looks south down the Atlantic coast from Cape Cod, Massachusetts, USA. But the longest and brightest trail is a Minotaur 1 rocket, a stage separation and exhaust plume visible along the rocket's fiery path toward low Earth orbit. The multi-stage Minotaur was launched from the Mid-Atlantic Regional Spaceport at NASA's Wallops Flight Facility at 8:15 pm Eastern Time in Virginia, about 400 miles away. On board were a remarkable 29 satellites destined for low Earth orbit, including a small cubesat built by high school students, and Firefly.

Image credit: Chris Cook
From California to the Pleiades (2013-11-22)

An astronomical trip from the California Nebula to the Pleiades star cluster would cover just over 12 degrees across planet Earth's night sky. That's equivalent to the angular extent of 25 Full Moons, as your telescope sweeps past the borders of the constellations Perseus and Taurus. This wide and deep mosaic image of the region explores the cosmic landscape's dusty nebulae and colors otherwise too faint for your eye to see. On the left, cataloged as NGC 1499, the California Nebula does have a familiar shape, though its coastline is actually over 60 light-years long and lies about 1,500 light-years away. The nebula's pronounced reddish glow is from hydrogen atoms ionized by luminous blue star Xi Persei seen just to its right. At the far right, the famous Pleiades star cluster is some 400 light-years distant and around 15 light-years across. Its spectacular blue color is due to the reflection of starlight by interstellar dust. In between are hot stars of the Perseus OB2 association and dusty, dark nebulae along the edge of the nearby, massive Perseus molecular cloud.

Image credit: Rogelio Bernal
Andreo
Comet ISON from STEREO (2013-11-23)

Still intact, on November 21 Comet ISON (C/2012 S1) swept into this animated field of view (left) from the HI-1 camera on the STEREO-A spacecraft. The camera has also captured periodic Comet Encke, Mercury, and Earth, with the Sun cropped out of the frame at the right, the source of the billowing solar wind. From STEREO's perspective in interplanetary space, planet Earth is actually the most distant of the group, seen in its orbit beyond the Sun. Mercury is closest, but both planets are still so bright they create sharp vertical lines in the camera's detector. Both comets clearly sport substantial tails, but ISON is closer to the camera and will continue to move more rapidly through the field. Cameras on STEREO and SOHO spacecraft will be able to follow Comet ISON as it falls towards its close encounter with the Sun on November 28, even as ISON gets more difficult to see in the bright dawn skies of planet Earth.
Comet Hale-Bopp Over Indian Cove (2013-11-24)

Comet Hale-Bopp, the Great Comet of 1997, was quite a sight. In the above photograph taken on 1997 April 6, Comet Hale-Bopp was imaged from the Indian Cove Campground in the Joshua Tree National Park in California, USA.  A flashlight was used to momentarily illuminate foreground rocks in this six minute exposure.  An impressive blue ion tail was visible above a sunlight-reflecting white dust tail. Comet Hale-Bopp remained visible to the unaided eye for over a year before returning to the outer Solar System and fading. As Comet ISON approaches the Sun this week, sky enthusiasts around the Earth are waiting to see if its tails will become even more spectacular than those displayed by Comet Hale-Bopp.   Happy Holidays: Free APOD 2014 Calendar in PDF format

Image credit: Wally Pacholka 
(Astropics,
TWAN)
Anemic Spiral NGC 4921 from Hubble (2013-11-25)

How far away is spiral galaxy NGC 4921? Although presently estimated to be about 310 million light years distant, a more precise determination could be coupled with its known recession speed to help humanity better calibrate the expansion rate of the entire visible universe.  Toward this goal, several images were taken by the Hubble Space Telescope in order to help identify key stellar distance markers known as Cepheid variable stars.   Since NGC 4921 is a member of the Coma Cluster of Galaxies, refining its distance would also allow a better distance determination to one of the largest nearby clusters in the local universe. The magnificent spiral NGC 4921 has been informally dubbed anemic because of its low rate of star formation and low surface brightness. Visible in the above image are, from the center, a bright nucleus, a bright central bar, a prominent ring of dark dust, blue clusters of recently formed stars, several smaller companion galaxies, unrelated galaxies in the far distant universe, and unrelated stars in our Milky Way Galaxy.    Free lecture: APOD editor to speak in NYC on Jan. 3
Cap Cloud over the Sierra Nevadas (2013-11-26)

One might say this was a bell weather day for the Sierra Nevada mountains.  In January, just as the Sun was setting above the district of Albayz�n in Grenada, Spain, a huge cloud appeared as a bell capping the Veleta peak.  Such a Cap cloud is formed by air forced upwards by a mountain peak, with the air then cooling, saturating with moisture, and finally having its molecular water condense into cloud droplets. Such a bell-shaped cloud structure is unusual as air typically moves horizontally, making most clouds nearly flat across at the bottom.  Vertical waves can also give additional lenticular cloud layers, as also seen above. Given the fleeting extent of the great cloud coupled with momentarily excellent sunset coloring, one might considered this also a bellwether day for an accomplished photographer.   Print or Peruse: Free APOD 2014 Calendar in PDF format

Image credit: Guido Monta��s
Comet ISON Rising (2013-11-27)

Will Comet ISON survive tomorrow's close encounter with the Sun? Approaching to within a solar diameter of the Sun's surface, the fate of one of the most unusual comets of modern times will finally be determined. The comet could shed a great amount of ice and dust into a developing tail -- or break apart completely. Unfortunately, the closer Comet ISON gets to the Sun, the harder it has been for conventional telescopes to see the brightening comet in the glare of the morning Sun. Pictured in the above short time lapse video, Comet ISON was captured rising over the Canary Islands just above the morning Sun a few days ago. If the comet's nucleus survives, the coma and the tails it sheds might well be visible rising ahead of the Sun in the next few days or weeks. Alternatively, satellites watching the Sun might document one of the larger comet disintegrations yet recorded. Stay tuned!   Watch: Comet ISON appoach an active Sun (Direct SOHO link)

Image credit: Juan Carlos Casado
NGC 1999: South of Orion (2013-11-28)

South of the large star-forming region known as the Orion Nebula, lies bright blue reflection nebula NGC 1999. At the edge of the Orion molecular cloud complex some 1,500 light-years distant, NGC 1999's illumination is provided by the embedded variable star V380 Orionis. That nebula is marked with a dark sideways T-shape near center in this cosmic vista that spans about 10 light-years. The dark shape was once assumed to be an obscuring dust cloud seen in silhouette against the bright reflection nebula. But recent infrared images indicate the shape is likely a hole blown through the nebula itself by energetic young stars. In fact, this region abounds with energetic young stars producing jets and outflows with luminous shock waves. Cataloged as Herbig-Haro (HH) objects, named for astronomers George Herbig and Guillermo Haro, the shocks look like red gashes in this scene that includes HH1 and HH2 just below NGC 1999. The stellar jets push through the surrounding material at speeds of hundreds of kilometers per second.  Comet ISON: Observing Campaign | SOHO | SDO | STEREO | Hangout
Comet ISON Before and After (2013-11-29)

Sungrazing Comet ISON reached perihelion, its closest approach to the Sun, yesterday, November 28, at 18:45 UT. The comet passed just over 1 million kilometers above the solar surface, a distance less than the diameter of the Sun. These two panels follow ISON before (right) and after its close approach, imaged by the LASCO instrument onboard the Sun staring SOHO spacecraft. Overwhelming sunlight is blocked by LASCO's central occulting disk with a white circle indicating the Sun's positon and scale. The bright comet is seen along its path at the bottom of the before panel, but something much fainter exits near the top of the after panel, potentially a dust tail reforming from the debris left from ISON's perihelion passage.
Surprising Comet ISON (2013-11-30)

After failing to appear for Sun staring spacecraft at perihelion, its harrowing closest approach to the Sun, sungrazing Comet ISON was presumed lost. But ISON surprised observers yesterday as material still traveling along the comet's trajectory became visible and even developed an extensive fan-shaped dust tail. Edited and processed to HD format, this video (vimeo, youtube) is composed of frames from the SOHO spacecraft's coronographs. It follows the comet in view of the wide (blue tint) and narrow (red tint) field cameras in the hours both before and after perihelion passage. In both fields, overwhelming sunlight is blocked by a central occulting disk. A white circle indicates the Sun's positon and scale. With questions to be answered and the tantalizing possibility that a small cometary nucleus has survived in whole or part, surprising comet ISON will be rising before dawn in planet Earth's skies in the coming days.
A Laser Strike at the Galactic Center (2013-12-01)

Why are these people shooting a powerful laser into the center of our Galaxy?  Fortunately, this is not meant to be the first step in a Galactic war.  Rather, astronomers at the Very Large Telescope (VLT) site in Chile are trying to measure the distortions of Earth's ever changing atmosphere.  Constant imaging of high-altitude atoms excited by the laser -- which appear like an artificial star -- allow astronomers to instantly measure atmospheric blurring.  This information is fed back to a VLT telescope mirror which is then slightly deformed to minimize this blurring.  In this case, a VLT was observing our Galaxy's center, and so Earth's atmospheric blurring in that direction was needed.  As for inter-galaxy warfare, when viewed from our Galaxy's center, no casualties are expected.  In fact, the light from this powerful laser would combine with light from our Sun to together appear only as bright as a faint and distant star.    If Time Continues: Free APOD 2014 Calendar in PDF format
Comet Lovejoy Before Galaxy M63 (2013-12-02)

Comet Lovejoy was captured last week passing well in front of spiral galaxy M63. Discovered only three months ago and currently near its maximum brightness, Comet Lovejoy can be seen near the Big Dipper from dark northerly locations before dawn with the unaided eye. An unexpected rival to Comet ISON, C/2013 R1 (Lovejoy), pictured above, is currently sporting a large green coma and a beautifully textured ion tail. Comet Lovejoy is now headed back to the outer Solar System but should remain a good sight in binoculars for another few weeks. Conversely, spiral galaxy M63, lies far in the distance and is expected to remain stationary on the sky and hold its relative brightness for at least the next few million years.   Late ISON News: The continuing saga of Comet ISON | In memoriam

Image credit: Damian Peach
The Colorful Clouds of Rho Ophiuchi (2013-12-03)

The many spectacular colors of the Rho Ophiuchi (oh'-fee-yu-kee) clouds highlight the many processes that occur there.  The blue regions shine primarily by reflected light.  Blue light from the star Rho Ophiuchi and nearby stars reflects more efficiently off this portion of the nebula than red light.  The Earth's daytime sky appears blue for the same reason.  The red and yellow regions shine primarily because of emission from the nebula's atomic and molecular gas.  Light from nearby blue stars - more energetic than the bright star  Antares - knocks electrons away from the gas, which then shines when the electrons recombine with the gas.  The dark brown regions are caused by dust grains - born in young stellar atmospheres - which effectively block light emitted behind them.  The Rho Ophiuchi star clouds, well in front of the globular cluster M4 visible  above on lower left, are even more colorful than humans can see - the clouds emits light in every wavelength band from the radio to the gamma-ray.   Budget Universe: Free APOD 2014 Calendar in PDF format

Image credit: Rafael Defavari
Comet Lovejoy through M�rby Castle Ruins (2013-12-04)

This new comet is quite photogenic. Comet Lovejoy, discovered only three months ago, was imaged through ruins of ancient M�rby Castle in Sweden last week sporting a green-glowing coma and tails trailing several degrees. The past few weeks have been an unusually active time for comet watchers as four comets were visible simultaneously with binoculars: ISON, Lovejoy, Encke, and LINEAR. C/2013 R1 (Lovejoy) comet is currently visible to the unaided eye from a dark location. As Monday's new Moon will provide little glare, the next few days provide a good time to see Comet Lovejoy as it reaches its peak brightness. In two and a half weeks, Comet Lovejoy will reach its closest approach to the Sun at a distance just inside the orbital distance of the Earth.   Late ISON News: Multiple views from Sun-observing spacecraft

Image credit: Clear Skies
Planetary Nebula Abell 7 (2013-12-05)

Very faint planetary nebula Abell 7 is some 1,800 light-years distant, just south of Orion in planet Earth's skies in the constellation Lepus, The Hare. Surrounded by Milky Way stars and near the line-of-sight to distant background galaxies, its generally simple spherical shape, about 8 light-years in diameter, is outlined in this deep telescopic image. Within its confines are beautiful, more complex details enhanced by the use of narrowband filters. Emission from hydrogen and nitrogen is shown in reddish hues with oxygen emission mapped to a bluish-green color, giving Abell 7 a more natural appearance that would otherwise be much too faint to be appreciated by eye. A planetary nebula represents a very brief final phase in stellar evolution that our own Sun will experience 5 billion years hence, as the nebula's central, once sun-like star shrugs off its outer layers. Abell 7 itself is estimated to be 20,000 years old. Its central star is seen here as a fading white dwarf some 10 billion years old.

Image credit: Don Goldman
Gamma-Ray Earth and Sky (2013-12-06)

For an Earth-orbiting gamma-ray telescope, Earth is actually the brightest source of gamma-rays, the most energetic form of light. Gamma-rays from Earth are produced when high energy particles, cosmic rays from space, crash into the atmosphere. While that interaction blocks harmful radiation from reaching the surface, those gamma-rays dominate in this remarkable Earth and sky view from the orbiting Fermi Gamma-ray Space Telescope's Large Area Telescope. The image was constructed using only observations made when the center of our Milky Way galaxy was near the zenith, directly above the Fermi satellite. The zenith is mapped to the center of the field. The Earth and points near the nadir, directly below the satellite, are mapped to the edges of the field resulting in an Earth and all-sky projection from Fermi's orbital perspective. The color scheme shows low intensities of gamma-rays as blue and high intensities as yellowish hues on a logarithmic scale. Our fair planet's brighter gamma-ray glow floods the edges of field, the high intensity yellow ring tracing Earth's limb. Gamma-ray sources in the sky along the relatively faint Milky Way stretch diagonally across the middle. Launched June 11, 2008 to explore the high-energy Universe, this week Fermi celebrated its 2,000th day in low Earth orbit.
Naked Eye Nova Centauri 2013 (2013-12-07)

Brightest stellar beacons of the constellation Centaurus, Alpha and Beta Centauri are easy to spot from the southern hemisphere. For now, so is new naked eye Nova Centauri 2013. In this night skyscape recorded near Las Campanas Observatory in the Chilean southern Atacama desert on December 5, the new star joins the old in the expansive constellation, seen at early morning hours through a greenish airglow. Caught by nova hunter John Seach from Australia on December 2 as it approached near naked eye brightness, Nova Cen 2013 has been spectroscopically identified as a classical nova, an interacting binary star system composed of a dense, hot white dwarf and cool, giant companion. Material from the companion star builds up as it falls onto the white dwarf's surface triggering a thermonuclear event. The cataclysmic blast results in a drastic increase in brightness and an expanding shell of debris. The stars are not destroyed, though. Classical novae are thought to recur when the flow of material onto the white dwarf eventually resumes and produces another outburst.

Image credit: Yuri Beletsky
Everest Panorama from Mars (2013-12-08)

If you could stand on Mars -- what might you see? Scroll right to find out.  The robotic Spirit rover that rolled around Mars from 2004 to 2009  Mars climbed to the top of a hill in 2005 and took a series of images over three days that were then digitally combined into a 360 degree panorama.  Spirit was instructed to take images having the same resolution as a human with 20-20 eyesight.  The full panoramic result can be found by clicking on the above image and has a level of detail unparalleled in the history of Martian surface photography.  The panorama was taken from the pinnacle of Husband Hill and has been dubbed the Everest panorama, in honor of the view from the tallest mountain on Earth.  Visible in Gusev Crater are rocks, rusting sand, a Martian sundial, vast plains, nearby peaks, faraway peaks, and sand drifts.  In the distance, fast moving dust devils can be seen as slight apparitions of red, green, or blue, the colors of filters used to build up this natural color vista.   Latest Images + Classic APODs: Look into the Sky on Facebook
Comet Lovejoy Over a Windmill (2013-12-09)

Lovejoy continues to be an impressive camera comet. Pictured above, Comet C/2013 R1 (Lovejoy) was imaged above the windmill in Saint-Michel-l'Observatoire in southern France with a six-second exposure.  In the foreground is a field of lavender. Comet Lovejoy should remain available for photo opportunities for northern observers during much of December and during much of the night, although it will be fading as the month progresses and highest in the sky before sunrise. In person, the comet will be best viewed with binoculars. A giant dirty snowball, Comet Lovejoy last visited the inner Solar System about 7,000 years ago, around the time that humans developed the wheel.   Budget Universe: Free APOD 2014 Calendar in PDF format

Image credit: Jens Hackmann
Seyfert's Sextet (2013-12-10)

What will survive this battle of the galaxies?  Known as Seyfert's Sextet, this intriguing group of galaxies lies in the head portion of the split constellation of the Snake (Serpens). The sextet actually contains only four interacting galaxies, though. Near the center of this Hubble Space Telescope picture, the small face-on spiral galaxy lies in the distant background and appears only by chance aligned with the main group. Also, the prominent condensation on the upper left is likely not a separate galaxy at all, but a tidal tail of stars flung out by the galaxies' gravitational interactions. About 190 million light-years away, the interacting galaxies are tightly packed into a region around 100,000 light-years across, comparable to the size of our own Milky Way galaxy, making this one of the densest known galaxy groups. Bound by gravity, the close-knit group may coalesce into a single large galaxy over the next few billion years.   Free lecture: APOD editor to speak in NYC on Jan. 3
The Coldest Place on Earth (2013-12-11)

How cold can it get on Earth? In the interior of the Antarctica, a record low temperature of -93.2 �C (-135.8 �F) has been recorded.  This is about 25 �C (45 �F) colder than the coldest lows noted for any place humans live permanently. The record temperature occurred in 2010 August -- winter in Antarctica -- and was found by scientists sifting through decades of climate data taken by Earth-orbiting satellites. The coldest spots were found near peaks because higher air is generally colder, although specifically in depressions near these peaks because relatively dense cold air settled there and was further cooled by the frozen ground.  Summer is a much better time to visit Antarctica, as some regions will warm up as high as 15 �C (59 �F).   Astrophysicists: Browse 600+ codes in the Astrophysics Source Code Library
Alnitak, Alnilam, Mintaka (2013-12-12)

Alnitak, Alnilam, and Mintaka, are the bright bluish stars from east to west (lower right to upper left) along the diagonal in this gorgeous cosmic vista. Otherwise known as the Belt of Orion, these three blue supergiant stars are hotter and much more massive than the Sun. They lie about 1,500 light-years away, born of Orion's well-studied interstellar clouds. In fact, clouds of gas and dust adrift in this region have intriguing and some surprisingly familiar shapes, including the dark Horsehead Nebula and Flame Nebula near Alnitak at the lower right. The famous Orion Nebula itself is off the right edge of this colorful star field. The well-framed, wide-field telescopic image spans about 4 degrees on the sky.  Watch: The Geminid Meteor Shower

Image credit: Rogelio Bernal
Andreo
Geminid Meteor Shower over Dashanbao Wetlands (2013-12-13)

The annual Geminid meteor shower is raining down on planet Earth this week. Despite the waxing gibbous moonlight, the reliable Geminids should be enjoyable tonight (night of December 13/14) near the shower's peak. Recorded near last year's peak in the early hours of December 14, 2012, this skyscape captures many of Gemini's lovely shooting stars. The careful composite of exposures was made during a three hour period overlooking the Dashanbao Wetlands in central China. Dark skies above are shared with bright Jupiter (right), Orion, (right of center) and the faint band of the Milky Way. The shower's radiant in the constellation Gemini, the apparent source of all the meteor streaks, lies just above the top of the frame. Dust swept up from the orbit of active asteroid 3200 Phaethon, Gemini's meteors enter the atmosphere traveling at about 22 kilometers per second.  Watch Tonight: The Geminid Meteor Shower

Image credit: Jeff Dai
The Bubble Nebula (2013-12-14)

Blown by the wind from a massive star, this interstellar apparition has a surprisingly familiar shape. Cataloged as NGC 7635, it is also known simply as The Bubble Nebula. Although it looks delicate, the 10 light-year diameter bubble offers evidence of violent processes at work. Above and right of the Bubble's center is a hot, O star, several hundred thousand times more luminous and around 45 times more massive than the Sun. A fierce stellar wind and intense radiation from that star has blasted out the structure of glowing gas against denser material in a surrounding molecular cloud. The intriguing Bubble Nebula lies a mere 11,000 light-years away toward the boastful constellation Cassiopeia. This natural looking view of the cosmic bubble is composed from narrowband image data, also used to create a 3D model.

Image credit: Astro Anarchy