omnianasa/nasa-apod-metadata huggingface dataset:
Jupiter in Ultraviolet from Hubble (2018-10-16)
Jupiter looks a bit different in ultraviolet light.  To better interpret  Jupiter's cloud motions and to help NASA's robotic Juno spacecraft understand the planetary context of the small fields that it sees, the Hubble Space Telescope is being directed to regularly image the entire Jovian giant. The colors of Jupiter being monitored go beyond the normal human visual range to include both ultraviolet and (not pictured) infrared light.  Featured from 2017, Jupiter appears different in near ultraviolet light, partly because the amount of sunlight reflected back is distinct, giving differing cloud heights and latitudes discrepant brightnesses. In the near UV, Jupiter's poles appear relatively dark, as does its Great Red Spot and a smaller (optically) white oval to the right.  The String of Pearl storms farther to the right, however, are brightest in near ultraviolet, and so here appear (false-color) pink.  Jupiter's largest moon Ganymede appears on the upper left. Juno continues on its looping 53-day orbits around Jupiter, while Earth-orbiting Hubble is now recovering from the loss of a stabilizing gyroscope.
M15: Dense Globular Star Cluster (2018-10-17)
Messier 15 is an immense swarm of over 100,000 stars. A 13 billion year old relic of the early formative years of our galaxy it's one of about 170 globular star clusters that still roam the halo of the Milky Way. Centered in this sharp telescopic view, M15 lies about 35,000 light years away toward the constellation Pegasus, well beyond the spiky foreground stars. Its diameter is about 200 light-years. But more than half its stars are packed into the central 10 light-years or so, one of the densest concentrations of stars known. Hubble-based measurements of the increasing velocities of M15's central stars are evidence that a massive black hole resides at the center of dense globular cluster M15.
Cherenkov Telescope at Sunset (2018-10-18)
On October 10, a new telescope reflected the light of the setting Sun. With dark horizon above and sunset colors below, its segmented mirror inverts an image of the beautiful evening sky in this snapshot from the Roque del Los Muchachos Observatory on the Canary Island of La Palma. The mirror segments cover a 23 meter diameter and are mounted in the open structure of the Large Scale Telescope 1, inaugurated as the first component of the Cherenkov Telescope Array (CTA). Most ground-based telescopes are hindered by the atmosphere that blurs, scatters, and absorbs light. But cherenkov telescopes are designed to detect very high energy gamma rays and actually require the atmosphere to operate. As the gamma rays impact the upper atmosphere they produce air showers of high-energy particles. A large, fast camera at the common focus images the brief flashes of optical light, called Cherenkov light, created by the air shower particles. The flashes reveal the incoming gamma ray timing, direction, and energy. Ultimately more than 100 Cherenkov telescopes are planned for the CTA at locations in both northern and southern hemispheres on planet Earth.
Summer to Winter Milky Way (2018-10-19)
Taken near local midnight, this autumn night's panorama follows the arch of the Milky Way across the northern horizon from the High Fens, Eifel Nature Park at the border of Belgium and Germany. Shift your gaze across the wetlands from west to east (left to right) and you can watch stars once more prominent in northern summer give way to those that will soon dominate northern winter nights. Setting, wanderer Mars is brightest at the far left, still shining against almost overwhelming city lights along the southwestern horizon. Bright stars Altair, Deneb, and Vega form the northern sky's summer triangle, straddling the Milky Way left of center. Part of the winter hexagon Capella and Aldebaran, along with the beautiful Pleiades star cluster shine across the northeastern sky. The line-of-sight along the hikers boardwalk leads almost directly toward the Big Dipper, an all season asterism from these northern latitudes. Follow the Big Dipper's pointer stars to Polaris and the north celestial pole nearly centered above it. Andromeda, the other large galaxy in the skyscape, is near the top of the frame.
Halo of the Cat's Eye (2018-10-20)
Not a Falcon 9 rocket launch after sunset, the Cat's Eye Nebula (NGC 6543) is one of the best known planetary nebulae in the sky. Its haunting symmetries are seen in the very central region of this composited picture, processed to reveal an enormous but extremely faint halo of gaseous material, over three light-years across. Made with data from ground- and space-based telescopes it shows the extended emission which surrounds the brighter, familiar planetary nebula. Planetary nebulae have long been appreciated as a final phase in the life of a sun-like star. But only more recently have some planetaries been found to have halos like this one, likely formed of material shrugged off during earlier active episodes in the star's evolution. While the planetary nebula phase is thought to last for around 10,000 years, astronomers estimate the outer filamentary portions of this halo to be 50,000 to 90,000 years old.
Meteor, Comet, and Seagull (Nebula) (2018-10-21)
A meteor, a comet, and a photogenic nebula have all been captured in this single image.  The closest and most fleeting is the streaking meteor on the upper right -- it was visible for less than a second. The meteor, which disintegrated in Earth's atmosphere, was likely a small bit of debris from the nucleus of Comet 21P/Giacobini-Zinner, coincidentally the comet captured in the same image. Comet 21P, pictured across the inner Solar System from Earth, is distinctive for its long dust tail spread horizontally across the image center.  This comet has been visible with binoculars for the past few months but is now fading as it heads back out to the orbit of Jupiter.  Farthest out at 3,500 light years distant is the IC 2177, the Seagull Nebula, visible on the left.  The comparatively vast Seagull Nebula, with a wingspan on order 250 light-years, will likely remain visible for hundreds of thousands of years.  Long exposures, taken about two weeks ago from Iwaki-City in Japan, were combined to capture the image's faintest elements.  You, too, could see a meteor like this -- and perhaps sooner than you might think: tonight is the peak of the Orionids meteor shower.
Apollo 12 Visits Surveyor 3 (2018-10-22)
Apollo 12 was the second mission to land humans on the Moon. The landing site was picked to be near the location of Surveyor 3, a robot spacecraft that had landed on the Moon three years earlier. In the featured photograph, taken by lunar module pilot Alan Bean, mission commander Pete Conrad jiggles the Surveyor spacecraft to see how firmly it is situated. The lunar module is visible in the distance.  Apollo 12 brought back many photographs and moon rocks.  Among the milestones achieved by Apollo 12 was the deployment of the Apollo Lunar Surface Experiments Package, which carried out many experiments including one that measured the solar wind.
Hyperion: Largest Known Galaxy Proto-Supercluster (2018-10-23)
How did galaxies form in the early universe? To help find out, astronomers surveyed a patch of dark night sky with the Very Large Telescope array in Chile to find and count galaxies that formed when our universe was very young. Analysis of the distribution of some distant galaxies (redshifts near 2.5) found an enormous conglomeration of galaxies that spanned 300 million light years and contained about 5,000 times the mass of our Milky Way Galaxy.  Dubbed Hyperion, it is currently the largest and most massive proto-supercluster yet discovered in the early universe. A proto-supercluster is a group of young galaxies that is gravitationally collapsing to create a supercluster, which itself a group of several galaxy clusters, which itself is a group of hundreds of galaxies, which itself is a group of billions of stars. In the featured visualization, massive galaxies are depicted in white, while regions containing a large amount of smaller galaxies are shaded blue.  Identifying and understanding such large groups of early galaxies contributes to humanity's understanding of the composition and evolution of the universe as a whole.
Light Pillars over Whitefish Bay (2018-10-24)
What's happening in the sky? Unusual lights appeared last week to hover above Whitefish Bay on the eastern edge of Lake Superior between the USA and Canada. Unsure of the cause, the Michigan-based astrophotographer switched camera lenses -- from fisheye to telephoto -- and soon realized he was seeing light pillars: vertical lines of light over a ground source that reflect from falling ice crystals.  As the ground temperature was above freezing, the flat crystals likely melted as they approached the ground, creating a lower end to the vertical light pillars.  The red ground lights originated from wind turbines on Ile Parisienne, a Canadian Island visible across the bay.
Barnard 150: Seahorse in Cepheus (2018-10-25)
Light-years across, this suggestive shape known as the Seahorse Nebula appears in silhouette against a rich, luminous background of stars. Seen toward the royal northern constellation of Cepheus, the dusty, obscuring clouds are part of a Milky Way molecular cloud some 1,200 light-years distant. It is also listed as Barnard 150 (B150), one of 182 dark markings of the sky cataloged in the early 20th century by astronomer E. E. Barnard. Packs of low mass stars are forming within from collapsing cores only visible at long infrared wavelengths. Still, colorful stars in Cepheus add to the pretty, galactic skyscape.
IC 59 and IC 63 in Cassiopeia (2018-10-26)
These bright rims and flowing shapes look ghostly on a cosmic scale. A telescopic view toward the constellation Cassiopeia, the colorful (zoomable) skyscape features the swept-back, comet-shaped clouds IC 59 (left) and IC 63. About 600 light-years distant, the clouds aren't actually ghosts, but they are slowly disappearing under the influence of energetic radiation from hot,luminous star gamma Cas. Gamma Cas is physically located only 3 to 4 light-years from the nebulae, just off the top right edge of the frame. Slightly closer to gamma Cas, IC 63 is dominated by red H-alpha light emitted as hydrogen atoms ionized by the star's ultraviolet radiation recombine with electrons. Farther from the star, IC 59 shows proportionally less H-alpha emission but more of the characteristic blue tint of dust reflected star light. The field of view spans about 1 degree or 10 light-years at the estimated distance of gamma Cas and friends.
Airglow Borealis (2018-10-27)
The best known asterism in northern skies hangs over the Canadian Rockies in this mountain and night skyscape taken last week from Banff National Park. But most remarkable is the amazing greenish airglow. With airglow visible to the eye, but not in color, the scene was captured in two exposures with a single camera, one exposure made while tracking the stars and one fixed to a tripod. Airglow emission is predominately from atmospheric oxygen atoms at extremely low densities. Commonly recorded in color by sensitive digital cameras the eerie, diffuse light is seen here in waves across the northern night. Originating at an altitude similar to aurorae, the luminous airglow is due to chemiluminescence, the production of light through chemical excitation and radiative decay. Energy for the chemical excitation is provided during daytime by the Sun's extreme ultraviolet radiation. Unlike aurorae which are limited to high latitudes, airglow can be found around the globe.
Ultraviolet Earth from an Observatory on the Moon (2018-10-28)
Which planet is this? Earth.  The featured false color picture shows how the Earth shines in ultraviolet (UV) light.  The image is historic because it was taken from the surface of the Moon by humanity's first lunar observatory.  (Another is operating now.)  Although very little UV light is transmitted through the Earth's atmosphere, what sunlight does make it through might cause a sunburn.  The part of the Earth facing the Sun reflects much UV light, but perhaps more interesting is the side facing away from the Sun.  Here bands of UV emission are the result of auroras and are caused by charged particles expelled by the Sun. Other planets showing auroras in the UV include Mars, Saturn, Jupiter, and Uranus.
Shells of Stars in Elliptical Galaxy PGC 42871 (2018-10-29)
How do galaxies grow? To help find out, the Hubble Space Telescope was deployed to image the unusual elliptical galaxy PGC 42871. How this galaxy came to be surrounded by numerous shells of stars may give clues about how it evolved.  Embedded in the diffuse shells are massive globular clusters of stars -- stars which analyses show were born during three different epochs.  This and other data indicate that PGC 42871 has been in at least two galactic collisions, at least one of which might have been with a former spiral galaxy. The remaining spiral galaxy on the far left is at the same distance as PGC 42871 and may have been involved in some of the collisions.  PGC 42871 spans about 20 thousand light years and lies about 270 million light years away toward the constellation of Centaurus.    Open Science: Browse 1,800+ codes in the Astrophysics Source Code Library
Orionids Meteors over Inner Mongolia (2018-10-30)
Meteors have been shooting out from the constellation of Orion.  This was expected, as October is the time of year for the Orionids Meteor Shower.  Pictured here, over two dozen meteors were caught in successively added exposures last October over Wulan Hada volcano in Inner Mongolia, China. The featured image shows multiple meteor streaks that can all be connected to a single small region on the sky called the radiant, here visible just above and to the left of the belt of Orion,  The Orionids meteors started as sand sized bits expelled from Comet Halley during one of its trips to the inner Solar System.  Comet Halley is actually responsible for two known meteor showers, the other known as the Eta Aquarids and visible every May.  An Orionids image featured on APOD one year ago today from the same location shows the same car.  Next month, the Leonids Meteor Shower from Comet Tempel-Tuttle should also result in some bright meteor streaks.   Follow APOD on: Facebook,  Instagram, Reddit, or Twitter
R Leporis: A Vampire's Star (2018-10-31)
Better known as Hind's Crimson Star, R Leporis is a rare star in planet Earth's night sky. It's also a shocking shade of red. The star's discoverer, 19th century English astronomer John Russell Hind, reported that it appeared in a telescope "... like a drop of blood on a black field." Located 1,360 light-years away in the constellation Lepus the star is a Mira-type variable, changing its brightness over a period of about 14 months. R Leporis is now recognized as a carbon star, a very cool and highly evolved red giant with an extreme abundance of carbon. Extra carbon in carbon stars is created by helium fusion near the dying stellar core and dredged up into the stars' outer layers. The dredge-up results in an overabundance of simple carbon molecules, like CO, CH, CN, and C2. While it's true that cool stars radiate most of their energy in red and infrared light, the carbon molecules strongly absorb what little blue light is left and give carbon stars an exceptionally deep red color.  R Leporis is losing its carbon-rich atmosphere into the surrounding interstellar material through a strong stellar wind though, and could be near the transition to a planetary nebula. Oh, and Happy Halloween from the folks at APOD.
Cygnus Shell Supernova Remnant W63 (2018-11-02)
The ghost of a long-dead star, the W63 supernova remnant shines like a faint cosmic smoke-ring along the plane of the Milky Way galaxy toward the northern constellation Cygnus the swan. Its wraithlike appearance is traced against the region's rich complex of interstellar clouds and dust by an eerie blue glow. Spanning over four full moons on the sky, the beautiful image is a telescopic mosaic in twelve panels that combines 100 hours of exposure time using narrow band filters. It shows characteristic light from ionized atoms of sulfur, hydrogen and oxygen in red, green, and blue hues. Likely over 5,000 light-years away, the visible part of the still expanding shell supernova remnant is around 150 light-years in diameter. So far no source has been identified as with the remains of W63's original star. Light from the star's supernova explosion would have reached Earth over 15,000 years ago.
Lunar LOVE (2018-11-03)
A more creative search by a group of amateur astronomers in the Ehime Prefecture of Shikoku Island, Japan has found lunar L-O-V-E. Their secret was an examination of this sharp image of the First Quarter Moon. To discover it for yourself you'll need to look closely at details of the shadow and light along the terminator, the line between lunar night and day. Created by the contrast of shadowed crater floors with sunlit walls and ridges, the letter V is not too hard to find near the center of the image. Letters L and E are a bit more challenging though, but can be teased out of shadow and light along the terminator at the bottom. Of course, on the cratered surface of the Moon the O is easy ... . Moonwatchers on planet Earth should understand that like the famous lunar X, also seen here, these lunar letters are transient and only appear along the terminator in the hours around the Moon's first quarter phase. So your next chance for lunar L-O-V-E is the first quarter Moon on November 15.
Flying Saucer Crash Lands in Utah Desert (2018-11-04)
A flying saucer from outer space crash-landed in the Utah desert after being tracked by radar and chased by helicopters.  The year was 2004, and no space aliens were involved.  The saucer, pictured here, was the Genesis sample return capsule, part of a human-made robot Genesis spaceship launched in 2001 by NASA itself to study the Sun.  The unexpectedly hard landing at over 300 kilometers per hour occurred because the parachutes did not open as planned.  The Genesis mission had been orbiting the Sun collecting solar wind particles that are usually deflected away by Earth's magnetic field. Despite the crash landing, many return samples remained in good enough condition to analyze. So far, Genesis-related discoveries include new details about the composition of the Sun and how the abundance of some types of elements differ across the Solar System. These results have provided intriguing clues into details of how the Sun and planets formed billions of years ago.
IC 4592: The Blue Horsehead Reflection Nebula (2018-11-05)
Do you see the horse's head?   What you are seeing is not the famous Horsehead nebula toward Orion but rather a fainter nebula that only takes on a familiar form with deeper imaging.  The main part of the here imaged molecular cloud complex is a reflection nebula cataloged as IC 4592.  Reflection nebulas are actually made up of very fine dust that normally appears dark but can look quite blue when reflecting the light of energetic nearby stars.  In this case, the source of much of the reflected light is a star at the eye of the horse.  That star is part of Nu Scorpii, one of the brighter star systems toward the constellation of the Scorpion (Scorpius).   A second reflection nebula dubbed IC 4601 is visible surrounding two stars to the right of the image center.
NGC 1499: The California Nebula (2018-11-06)
There's even a California in space.  Drifting through the Orion Arm of the spiral Milky Way Galaxy, this cosmic cloud by chance echoes the outline of California on the west coast of the United States. Our own Sun also lies within the Milky Way's Orion Arm, only about 1,500 light-years from the California Nebula. Also known as NGC 1499, the classic emission nebula is around 100 light-years long. On the featured image, the most prominent glow of the California Nebula is the red light characteristic of hydrogen atoms recombining with long lost electrons, stripped away (ionized) by energetic starlight. The star most likely providing the energetic starlight that ionizes much of the nebular gas is the bright, hot, bluish Xi Persei just to the right of the nebula.  A regular target for astrophotographers, the California Nebula can be spotted with a wide-field telescope under a dark sky toward the constellation of Perseus, not far from the Pleiades.
NGC 6188: The Dragons of Ara (2018-11-07)
Dark shapes with bright edges winging their way through dusty NGC 6188 are tens of light-years long. The emission nebula is found near the edge of an otherwise dark large molecular cloud in the southern constellation Ara, about 4,000 light-years away. Born in that region only a few million years ago, the massive young stars of the embedded Ara OB1 association sculpt the fantastic shapes and power the nebular glow with stellar winds and intense ultraviolet radiation. The recent star formation itself was likely triggered by winds and supernova explosions, from previous generations of massive stars, that swept up and compressed the molecular gas. With image data from the Chilescope Observatory, a false-color Hubble palette was used to create this gorgeous wide-field image and shows emission from sulfur, hydrogen, and oxygen atoms in red, green, and blue hues. The field of view spans about four full Moons, corresponding to about 150 light years at the estimated distance of NGC 6188.
Mars in the Loop (2018-11-08)
This composite of images spaced some 5 to 9 days apart, from late April (bottom right) through November 5 (top left), traces the retrograde motion of ruddy-colored Mars through planet Earth's night sky. To connect the dots and dates in this 2018 Mars retrograde loop, just slide your cursor over the picture (and check out this animation). But Mars didn't actually reverse the direction of its orbit. Instead, the apparent backwards motion with respect to the background stars is a reflection of the motion of the Earth itself. Retrograde motion can be seen each time Earth overtakes and laps planets orbiting farther from the Sun, the Earth moving more rapidly through its own relatively close-in orbit.  On July 27, Mars was near its favorable 2018 perihelic opposition, when Mars was closest to the Sun in its orbit while also opposite the Sun in Earth's sky. For that date, the frame used in this composite was taken during the total lunar eclipse.
Little Planet Lookout (2018-11-09)
Don't panic. This little planet projection looks confusing, but it's actually just a digitally warped and stitched, nadir centered mosaic of images that covers nearly 360x180 degrees. The images were taken on the night of October 31 from a 30 meter tall hill-top lookout tower near Tatabanya, Hungary, planet Earth. The laticed lookout tower construction was converted from a local mine elevator. Since planet Earth is rotating, the 126 frames of 75 second long exposures also show warped, concentric star trails with the north celestial pole at the left. Of course at this location the south celestial pole is just right of center but below the the little planet's horizon.
The Old Moon in the Young Moon's Arms (2018-11-10)
Tonight the Moon is young again, but this stunning image of a young Moon near the western horizon was taken just after sunset on October 10. On the lunar disk Earthshine, earthlight reflected from the Moon's night side, is embraced by the slim, sunlit crescent just over 2 days old. Along the horizon fading colors of twilight silhouette the radio telescope dish antennas of the Very Large Array, New Mexico, planet Earth. The view from the Moon would be stunning, too. When the Moon appears in Earth's sky as a slender crescent, a dazzlingly bright, nearly full Earth would be seen from the lunar surface. A description of earthshine, in terms of sunlight reflected by Earth's oceans in turn illuminating the Moon's dark surface, was written 500 years ago by Leonardo da Vinci.