juliensimon/nasa-apod huggingface dataset:
Sharpless 171 (2008-10-18)

Cosmic pillars of cold molecular gas and clouds of dark dust lie within Sharpless 171, a star-forming region some 3,000 light-years away in the royal constellation Cepheus. This tantalizing false-color skyscape spans about 20 light-years across the nebula's bright central region. It also highlights the pervasive glow of emission from atomic gas using narrowband filters and a color palette made popular in Hubble Space Telescope images. Powering the nebular glow are the young, hot stars of a newly formed cluster, Berkeley 59. Of course, this star-forming region is entry number 171 in the famous 1959 catalog of emission nebulae compiled by astronomer Stewart Sharpless.

Image credit: Antonio Fernandez
In the Center of the Lagoon Nebula (2008-10-19)

The center of the Lagoon Nebula is a whirlwind of spectacular star formation. Visible on the upper left, at least two long funnel-shaped clouds, each roughly half a light-year long, have been formed by extreme stellar winds and intense energetic starlight.  The tremendously bright nearby star, Hershel 36, lights the area.  Vast walls of dust hide and redden other hot young stars.  As energy from these stars pours into the cool dust and gas, large temperature differences in adjoining regions can be created generating shearing winds which may cause the funnels.  This picture, spanning about 5 light years, was taken in 1995 by the orbiting Hubble Space Telescope.  The Lagoon Nebula, also known as M8, lies about 5000 light years distant toward the constellation of Sagittarius.
Moons, Rings, and Unexpected Colors on Saturn (2008-10-20)

Why would Saturn show such strange colors? The robotic Cassini spacecraft currently orbiting Saturn has beamed back images showing that the northern hemisphere our Solar System's most spectacularly ringed planet has changed noticeably since Cassini arrived in 2004, now sporting unusual and unexpected colors. No one is sure why.  Although the cause for many of Saturn's colors is unknown, the recent change in colors is thought to be related to the changing seasons.  Pictured above, the unusual colors are visible just north of the dark ring shadows. The razor-thin plane of ring particles is visible nearly edge-on across the bottom of the image. The cloudy moon Titan looms large just above the rings, while close observation will reveal three other moons.   Cassini arrived at Saturn in 2004, sending back data and images that have not only led to a deeper understanding of the Jovian world's atmosphere, moons, and rings, but also raised new mysteries.
A Dark Pulsar in CTA 1 (2008-10-21)

Where's the pulsar?  Previously, the nebula CTA 1 showed an expanding supernova remnant, a jet, and a point source expected to be a pulsar -- a rotating neutron star producing pulses at radio energies. But no radio pulses were detected. Now NASA's recently deployed Fermi Space Telescope has solved the mystery with some of its initial observations indicating that the point source is pulsing at gamma-ray energies.  The strange source is the first of a class that might be dubbed "dark pulsars", rotating neutron stars that appear to pulse only in high-energy radiations. Such pulsars might not be detectable in radio or visible light if they emit those radiations into a narrow beam not seen from Earth. If true, our Galaxy might have more pulsars left for Fermi to discover. Studying the gamma-ray properties of pulsars gives valuable clues to physics of the emission regions on neutron stars. In this graphic, the pulsar's position is indicated in the wider CTA 1 supernova remnant.  An artist's illustration of the pulsar beaming at gamma-ray energies is shown in the inset.
Beautiful Spiral NGC 7331 (2008-10-22)

A favorite target for astronomers, big, beautiful spiral galaxy NGC 7331 is one of the brighter galaxies not found in Charles Messier's famous 18th century catalog. About 50 million light-years distant in the northern constellation Pegasus and similar in size to our own Milky Way Galaxy, NGC 7331 is often imaged as the foreground of a visual grouping that includes an intriguing assortment of background galaxies some ten times farther away. This striking image of the well-studied island universe and environs was produced using data from the Calar Alto Observatory in southern Spain. Perhaps the deepest view of the region yet, the image data were processed to reveal sharp details of all sizes in both bright and faint areas. A color balance was chosen so that white would be the result of averaging colors over the entire galaxy. The result shows off a wealth of remarkable features in NGC 7331 and its surroundings.

Image credit: Vicent Peris
Great Orion Nebulae (2008-10-23)

The Great Nebula in Orion, also known as M42, is one of the most famous nebulae in the sky. The star forming region's glowing gas clouds and hot young stars are on the right in this sharp and colorful two frame mosaic that includes the smaller nebula M43 near center and dusty, bluish reflection nebulae NGC 1977 and friends on the left. Located at the edge of an otherwise invisible giant molecular cloud complex, these eye-catching nebulae represent only a small fraction of this galactic neighborhood's wealth of interstellar material. Within the well-studied stellar nursery, astronomers have also identified what appear to be numerous infant solar systems. The gorgeous skyscape spans nearly two degrees or about 45 light-years at the Orion Nebula's estimated distance of 1,500 light-years.  Editor's Note: A version of the image with labels generated by Astrometry.net is available here.

Image credit: Tony Hallas
Amazing Comet Holmes (2008-10-24)

One year ago, Comet 17P/Holmes amazed sky watchers across planet Earth. A stunningly rapid outburst transformed it from a faint comet quietly orbiting the Sun with a period of about 7 years to a naked-eye comet rivaling the brighter stars in the constellation Perseus. Its largely tail-less shape, as in this wide-angle view recorded on November 11, 2007, became well-known to astronomers trying to unravel the mystery of the comet's surprising outburst . Still, Comet Holmes had a dim ion tail that was seen to separate from the bright coma. In this image, the separated tail creates the illusion of a reflection nebula. It appears as a faint bluish haze right of center against a background of stars in the loosely grouped Alpha Persei Moving Cluster.

Image credit: Tony Cook
NGC 602 and Beyond (2008-10-25)

Near the outskirts of the Small Magellanic Cloud, a satellite galaxy some 200 thousand light-years distant, lies 5 million year young star cluster NGC 602. Surrounded by natal gas and dust, NGC 602 is featured in this stunning Hubble image of the region. Fantastic ridges and swept back shapes strongly suggest that energetic radiation and shock waves from NGC 602's massive young stars have eroded the dusty material and triggered a progression of star formation moving away from the cluster's center. At the estimated distance of the Small Magellanic Cloud, the picture spans about 200 light-years, but a tantalizing assortment of background galaxies are also visible in the sharp Hubble view. The background galaxies are hundreds of millions of light-years or more beyond NGC 602.
Massive Stars in Open Cluster Pismis 24 (2008-10-26)

How massive can a normal star be?  Estimates made from distance, brightness and standard  solar models had given one star in the open cluster Pismis 24 over 200 times the mass of our Sun, making it a record holder.  This star is the brightest object located just above the gas front in the above image.  Close inspection of images taken recently with the Hubble Space Telescope, however, have shown that Pismis 24-1 derives its brilliant luminosity not from a single star but from three at least.  Component stars would still remain near 100 solar masses, making them among the more massive stars currently on record.  Toward the bottom of the image, stars are still forming in the associated emission nebula NGC 6357, including several that appear to be breaking out and illuminating a spectacular cocoon.
Beneath the South Pole of Saturn (2008-10-27)

What clouds lurk beneath Saturn's unusual South Pole? To help find out, the robotic Cassini spacecraft currently orbiting Saturn imaged the nether region of the gigantic ringed orb in infrared light. There thick clouds appear dark as they mask much of the infrared light emitted from warmer regions below, while relatively thin clouds appear much lighter.  Bands of clouds circle Saturn at several latitudes, while dark ovals indicate many dark swirling storm systems.  Surprisingly, a haze of upper level clouds visible towards Saturn's equator disappears near the pole, including over Saturn's strange polar vortex. Cassini entered orbit around Saturn in 2004, and recorded the above image last year.
The North America Nebula (2008-10-28)

The North America Nebula in the sky can do what most  North Americans on Earth cannot -- form stars.  Specifically, in analogy to the Earth-confined continent, the bright part that appears as Central America and Mexico is actually a hot bed of gas, dust, and newly formed stars known as the Cygnus Wall.  This beautiful skyscape shows the star forming wall lit and eroded by bright young stars, and partly hidden by the dark dust they have created.  The North America Nebula (NGC 7000) spans about 50 light years and lies about 1,500 light years away toward the constellation of the Swan (Cygnus).

Image credit: Ignacio Rico Gualda
Mirach's Ghost (2008-10-29)

As far as ghosts go, Mirach's Ghost isn't really that scary. In fact, Mirach's Ghost is just a faint, fuzzy galaxy, well known to astronomers, that happens to be seen nearly along the line-of-sight to Mirach, a bright star. Centered in this star field, Mirach is also called Beta Andromedae. About 200 light-years distant, Mirach is a red giant star, cooler than the Sun but much larger and so intrinsically much brighter than our parent star. In most telescopic views, glare and diffraction spikes tend to hide things that lie near Mirach and make the faint, fuzzy galaxy look like a ghostly internal reflection of the almost overwhelming starlight. Still, appearing in this sharp image just above and to the right, Mirach's Ghost is cataloged as galaxy NGC 404 and is estimated to be some 10 million light-years away.  Take a survey on Aesthetics and Astronomy.

Image credit: Anthony Ayiomamitis
Haunting the Cepheus Flare (2008-10-30)

Spooky shapes seem to haunt this starry expanse, drifting through the night in the royal constellation Cepheus. Of course, the shapes are cosmic dust clouds faintly visible in dimly reflected starlight. Far from your own neighborhood on planet Earth, they lurk at the edge of the Cepheus Flare molecular cloud complex some 1,200 light-years away. Over 2 light-years across and brighter than the other ghostly apparitions, the nebula known as vdB 141 or Sh2-136 near the center of the field is even seen in infrared light. Also cataloged as Bok globule CB230, the core of that cloud is collapsing and is likely a binary star system in the early stages of formation.  Take a survey on Aesthetics and Astronomy.

Image credit: Giovanni Benintende
A Witch by Starlight (2008-10-31)

By starlight this eerie visage shines in the dark, a crooked profile evoking its popular name, the Witch Head Nebula. In fact, this entrancing telescopic portrait gives the impression the witch has fixed her gaze on Orion's bright supergiant star Rigel. Spanning over 50 light-years, the dusty cosmic cloud strongly reflects nearby Rigel's blue light, giving it the characteristic color of a reflection nebula. Cataloged as IC 2118, the Witch Head Nebula is about 1,000 light-years away. Of course, you might see a witch this scary tonight, but don't panic. Have a safe and Happy Halloween!  Take a survey on Aesthetics and Astronomy.

Image credit: Star Shadows
Remote Observatory
A Spectre in the Eastern Veil (2008-11-01)

Menacing flying forms and garish colors are a mark of the Halloween season. They also stand out in this cosmic close-up of the eastern Veil Nebula.  The Veil Nebula itself is a large supernova remnant, the expanding debris cloud from the death explosion of a massive star. While the Veil is roughly circular in shape covering nearly 3 degrees on the sky in the constellation Cygnus, this portion of the eastern Veil spans only 1/2 degree, about the apparent size of the Moon. That translates to 12 light-years at the Veil's estimated distance of 1,400 light-years from planet Earth. In this composite of image data recorded through narrow band filters, emission from hydrogen atoms in the remnant is shown in red with strong emission from oxygen atoms in greenish hues. In the western part of the Veil lies another seasonal apparition, the Witch's Broom.  Take a survey on Aesthetics and Astronomy.

Image credit: Paul Mortfield
Spicules: Jets on the Sun (2008-11-02)

Imagine a pipe as wide as a state and as long as half the Earth.  Now imagine that this pipe is filled with hot gas moving 50,000 kilometers per hour.  Further imagine that this pipe is not made of metal but a transparent magnetic field.  You are envisioning just one of thousands of young spicules on the active Sun.  Pictured above is perhaps the highest resolution image yet of these enigmatic solar flux tubes.  Spicules dot the above frame of solar active region 10380 that crossed the Sun in 2004 June, but are particularly evident as a carpet of dark tubes on the right.  Time-sequenced images have recently shown that spicules last about five minutes, starting out as tall tubes of rapidly rising gas but eventually fading as the gas peaks and falls back down to the Sun.  These images also indicate that the ultimate cause of spicules is sound-like waves that flow over the Sun's surface but leak into the Sun's atmosphere.
A Spectacular Rayed Crater on Mercury (2008-11-03)

Why does Mercury have so many rayed craters? No one is sure.  The robotic MESSENGER spacecraft that is taking unprecedented images as it swoops past the innermost planet has provided dramatic confirmation that Mercury has more rayed craters than Earth's Moon. Pictured above, a particularly spectacular rayed crater spanning approximately 80 kilometers was imaged by MESSENGER during last month's flyby from about 20,000 kilometers up.  The rays prevalence is a mystery because space weathering effects such as dust accumulation and solar wind attenuation should be greater on Mercury than on the Moon.  Hypothesized solutions currently include the optical properties of Mercurian dust, and that Mercury's high mass and proximity to the Sun cause more violent impacts, thus typically raising more light material. MESSENGER will buzz past Mercury again next year before entering orbit in 2011.
The Double Ring Galaxies of Arp 147 from Hubble (2008-11-04)

How could a galaxy become shaped like a ring?  Even more strange: how could two?  The rim of the blue galaxy pictured on the right shows an immense ring-like structure 30,000 light years in diameter composed of newly formed, extremely bright, massive stars.  This blue galaxy is part of the interacting galaxy system known as Arp 147, and shows a ring because it has recently collided with the other galaxy in the frame, the red galaxy on the left.  Unusually, even this red galaxy shows a ring like band, although it is seen nearly edge-on. When galaxies collide, they pass through each other -- their individual stars rarely come into contact.  Clouds of interstellar gas and dust become condensed, causing a wave of star formation to move out from the impact point like a ripple across the surface of a pond.  The above image was taken last week by NASA's Hubble Space Telescope to demonstrate the ability of its Wide Field Planetary Camera 2 after some recent technical difficulties.
Seventeen Hundred Kilometers Above Enceladus (2008-11-05)

Above is one of the closest pictures yet obtained of Saturn's ice-spewing moon Enceladus. The image was taken from about 1,700 kilometers up as the robotic Cassini spacecraft zoomed by the fractured ice ball last week.   Features the size of a bus are resolvable in this highly detailed image taken of Enceladus' active tiger stripe region. Very different from most other moons and planets, grooves and hills dot an alien moonscape devoid of craters. Space pioneers might wonder where, on such a highly textured surface, a future probe might land in search of freshly deposited ice, subsurface seas, or even indicators of life.  Although appearing dark in the above contrast-enhanced image, the surface of Enceladus is covered with some of the brightest ice in the entire Solar System, reflecting about 99 percent of the light it receives.  To help better understand this enigmatic world, Cassini is scheduled to swoop by Enceladus at least five more times.
A Sharper View of a Hazy Giant (2008-11-06)

This dramatic image of Jupiter is touted as the sharpest picture of the entire gas giant ever taken from the ground. The picture was made using a prototype instrument known as MAD (Multi-conjugate Adaptive optics Demonstrator) mounted on one of the European Southern Observatory's 8-meter diameter Very Large Telescope units in Chile. Working at infrared wavelengths the MAD instrument removes atmospheric blurring, the bane of earthbound telescopes, by using multiple guide stars and deformable mirrors to sense and correct for the distortions produced by turbulence in Earth's atmosphere. Hydrogen and methane deep in Jupiter's own thick atmosphere absorb light at infrared wavelengths. So, this sharper view shows the infrared sunlight reflected from the giant planet's high level haze prominent in the equatorial regions and near the poles. It reveals features as small as 300 kilometers across. The promising technique can also be applied to imaging other extended objects like star clusters and nebulae.  Take a survey on Aesthetics and Astronomy.
Cygnus Trio (2008-11-07)

In this colorful mosaic, filaments of gas and dust span some 9 degrees across central Cygnus, a nebula rich constellation along the northern Milky Way. A trio of nebulae with popular names highlights the beautiful skyscape - the Butterfly, the Crescent, and the Tulip. At left, the Butterfly Nebula (IC 1318), lies near bright star Gamma Cygni. The Butterfly's expansive, glowing, wing-shaped gas clouds are divided by a dark dust lane. Near center, the Crescent Nebula (NGC 6888) is more compact, a cosmic bubble with a bright edge blown by winds from a massive Wolf-Rayet star. On the right is the Tulip Nebula (Sh2-101), a small emission region shaped like a blossoming flower viewed from the side. All are within a few thousand light-years of the Sun in the Orion spiral arm of our galaxy. The gorgeous mosaic is presented in false color, constructed from image data recorded through narrow band filters. The range of colors was created by a mapping of emission from hydrogen, sulfur and oxygen atoms in the nebula to red, green, and blue hues.  Take a survey on Aesthetics and Astronomy.

Image credit: Astro Anarchy
On the Trail of 2008 TC3 (2008-11-08)

On October 7, the early dawn over northern Sudan revealed this twisted, high altitude trail. Captured in a video frame, the long-lasting persistent train is from the impact of a small asteroid cataloged as 2008 TC3. That event was remarkable because it was the first time an asteroid was detected in space before crashing into planet Earth's atmosphere. In fact, after astronomers discovered 2008 TC3, the time and location of its impact were predicted based on follow-up observations. Later, the impact predictions were confirmed by sensors, including a Meteosat-8 image of a bright flash in the atmosphere. Astronomers are now hoping for more reports of local ground-based observations of what must have been a brilliant meteor streaking through Sudan's night sky. Additional reports could improve the chances of recovering meteorites.  Take a survey on Aesthetics and Astronomy.
Two Black Holes Dancing in 3C 75 (2008-11-09)

What's happening at the center of active galaxy 3C 75?  The two bright sources at the center of this composite x-ray (blue)/ radio (pink) image are co-orbiting supermassive black holes powering the giant radio source 3C 75. Surrounded by multimillion degree x-ray emitting gas, and blasting out jets of relativistic particles the supermassive black holes are separated by 25,000 light-years. At the cores of two merging galaxies in the Abell 400 galaxy cluster they are some 300 million light-years away. Astronomers conclude that these two supermassive black holes are bound together by gravity in a binary system in part because the jets' consistent swept back appearance is most likely due to their common motion as they speed through the hot cluster gas at 1200 kilometers per second. Such spectacular cosmic mergers are thought to be common in crowded galaxy cluster environments in the distant universe. In their final stages the mergers are expected to be intense sources of gravitational waves.
Our Galaxy's Central Molecular Zone (2008-11-10)

The central region of our Milky Way Galaxy is a mysterious and complex place. Pictured here in radio and infrared light, the galaxy's central square degree is highlighted in fine detail. The region is known as the Central Molecular Zone. While much of the extended emission is due to dense gas laced with molecules, also seen are emission nebulas lit up by massive young stars, glowing supernova remnants, and the curving Galactic Center Radio Arc in purple. The identity and root cause for many other features remains unknown.  Besides a massive black hole named Sgr A*, the Galactic Center houses the galaxy's most active star forming region. This image is not just interesting scientifically. It's esthetic beauty won first prize this year in the AUI/NRAO Image Contest.
The Cosmic Web of the Tarantula Nebula (2008-11-11)

First cataloged as a star, 30 Doradus is actually an immense star forming region in nearby galaxy The Large Magellanic Cloud. The region's spidery appearance is responsible for its popular name, the Tarantula nebula, except that this tarantula is about 1,000 light-years across, and 180,000 light-years away in the southern constellation Dorado. If the Tarantula nebula were at the distance of the Orion Nebula (1,500 light-years), the nearest stellar nursery to Earth, it would appear to cover about 30 degrees (60 full moons) on the sky. The spindly arms of the Tarantula nebula surround NGC 2070, a star cluster that contains some of the brightest, most massive stars known. Intriguing details of the nebula are visible in this scientifically-colored image. The cosmic Tarantula also lies near the site of the closest recent supernova.

Image credit: Joseph Brimacombe
Phoenix and the Holy Cow (2008-11-12)

The northern Martian summer is waning. As predicted, a decline in daylight hours, deteriorating weather, and dust storms are preventing solar arrays on the Phoenix Mars Lander from providing power.  Phoenix's last signal was received on November 2, its successful mission ending after more than five months in the arctic region of the Red Planet, a run that exceeded its planned operational lifetime. Attempting to discover if Mars' surface has ever been able to support microbial life, Phoenix performed an extensive analysis of the soil and returned a wealth of image data. Of course, one of the lander's most exciting results was the detection of water-ice near the Martian surface. Recorded in October, this picture from the lander's Robotic Arm Camera shows the region under the Phoenix with flat, exposed icy patches. That area caused researchers to exclaim "Holy Cow!" when it was first imaged a few days after the May 25 touchdown of the Phoenix Mars Lander.