juliensimon/nasa-apod huggingface dataset:
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.

Image credit: Junichi Watanabe
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.

Image credit: Mario Cogo
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.

Image credit: Bray Falls
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.

Image credit: Tian Lee
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.

Image credit: Tunc Tezel
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.

Image credit: Gyorgy Soponyai
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.

Image credit: Stan Honda
Astronaut Exploring: An Apollo 15 Panorama (2018-11-11)

What would it be like to explore the Moon? NASA's Apollo missions gave humans just this chance in the late 1960s and early 1970s.  In particular, the Apollo 15 mission was dedicated to better understanding the surface of the Moon by exploring mountains, valleys, maria, and highlands. Astronauts David Scott and James Irwin spent nearly three days on the Moon while Alfred Worden orbited above in the Command Module.  The mission, which blasted off from Earth on 1971 July 26, was the first to deploy a Lunar Roving Vehicle.  Pictured in this digitally stitched mosaic panorama, David Scott, exploring his surroundings,  examines a boulder in front of the summit of Mt. Hadley Delta.  The shadow of James Irwin is visible to the right, while scrolling to the right will reveal a well-lit and diverse lunar terrain.  The Apollo 15 mission returned about 76 kilograms of moon rocks for detailed study.  In the future, NASA and other space agencies plan to continue to lead humanity's exploration of the Moon, Mars, and beyond.

Image credit: NASA, 
USGS, 
Apollo 15 Crew
The Lagoon Nebula is Stars, Gas, and Dust (2018-11-12)

The majestic Lagoon Nebula is filled with hot gas and the home for many young stars. Spanning 100 light years across while lying only about 5000 light years distant, the Lagoon Nebula is so big and bright that it can be seen without a telescope toward the constellation of the Archer (Sagittarius).  Many bright stars are visible from NGC 6530, an open cluster that formed in the nebula only several million years ago. The greater nebula, also known as M8 and NGC 6523, is named "Lagoon" for the band of dust seen to the left of the open cluster's center. The featured image was taken in three colors with details are brought out by light emitted by Hydrogen. Star formation continues in the Lagoon Nebula as witnessed by the many dark dust-laden globules that exist there.

Image credit: Nelson Ortega
Rotating Asteroid Bennu from OSIRIS-REx (2018-11-13)

Could this close-by asteroid ever hit the Earth? Eventually yes -- but probably not for a very long time, even though the asteroid is expected to pass inside the orbit of the Moon next century.  However, to better understand the nature and orbit of all near-Earth asteroids, NASA sent the robotic Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) to investigate this one: the 500-meter across asteroid 101955 Bennu. Launched in 2016, OSIRIS-REx is now approaching Bennu, and is first scheduled to map the minor planet's rough surface. The featured time-lapse video taken earlier this month compacts Bennu's 4.25-hour rotation period into about 7 seconds. Bennu's diamond-like appearance is similar to asteroid Ryugu currently being visited by the Japanese spacecraft Hayabusa2.  The exact future orbit of Bennu is a bit uncertain due to close passes near the Earth and the Yarkovsky effect: a slight force created by an object's rotationally-induced, asymmetric infrared glow.  If all goes according to plan, ORISIS-Rx will actually touch the asteroid in 2020, collect soil samples, and return them to Earth in 2023 for detailed analyses.
The Cave Nebula in Hydrogen, Oxygen, and Sulfur (2018-11-14)

What's inside this cosmic cave? A stellar nursery 10 light-years deep.  The featured skyscape is dominated by dusty Sh2-155, the Cave Nebula. In the telescopic image, data taken through a narrowband filters tracks the nebular glow of hydrogen, oxygen, and sulfur, colors that together form the Hubble Palette.  About 2,400 light-years away, the scene lies along the plane of our Milky Way Galaxy toward the royal northern constellation of Cepheus. Astronomical explorations of the region reveal that it has formed at the boundary of the massive Cepheus B molecular cloud and the hot, young stars of the Cepheus OB 3 association. The bright rim of ionized hydrogen gas is energized by radiation from the hot stars, dominated by the bright star just to the left of the cave entrance. Radiation driven ionization fronts are likely triggering collapsing cores and new star formation within.

Image credit: Chuck Ayoub
Comet 46P/Wirtanen (2018-11-15)

Periodic Comet 46P/Wirtanen is now the brightest comet in the night sky, but too faint to be seen by eye. From dark sky sites it could just become naked-eye visible though, as its 5.4 year long looping orbit takes it closest to Earth and the Sun in mid December. Fluorescing in sunlight, its spherical coma is about half the angular size of a full moon in this southern hemisphere telescopic view from November 7. Then the comet was about 2 light-minutes away or 35 million kilometers from Earth-bound telescopes, so the pretty greenish coma seen here is around 150,000 kilometers across. That makes it about the size of Jupiter. The stack of digital images also reveals a very faint tail extending toward 4 o'clock with a distant background galaxy notable at the upper left. As a regular visitor to the inner Solar System, comet 46P/Wirtanen was once the favored rendezvous target for ESA's comet exploring Rosetta mission.

Image credit: Terrastro
The Hill, The Moon, and Saturn (2018-11-16)

Last Sunday when the Moon was young its sunlit crescent hung low near the western horizon at sunset. With strong earthshine it was joined by Saturn shining in the early evening sky for a beautiful conjunction visible to skygazers around our fair planet. On that clear evening on a hill near Veszprem, Hungary mother, daughter, bright planet, and young Moon are framed in this quiet night skyscape taken with a telephoto lens. Of course the Moon ages too quickly for some, and by tonight the sunlit part has reached its first quarter phase. This weekend skygazers spending quality time under Moon and stars might expect to see the annual rain of comet dust otherwise known as the Leonid meteor shower.   How to: Photograph the Leonid Meteor Shower

Image credit: Tamas Ladanyi
The Tarantula Nebula (2018-11-17)

The Tarantula Nebula, also known as 30 Doradus, is more than a thousand light-years in diameter, a giant star forming region within nearby satellite galaxy the Large Magellanic Cloud. About 180 thousand light-years away, it's the largest, most violent star forming region known in the whole Local Group of galaxies. The cosmic arachnid sprawls across this spectacular view, composed with narrowband filter data centered on emission from ionized hydrogen atoms. Within the Tarantula (NGC 2070), intense radiation, stellar winds and supernova shocks from the central young cluster of massive stars, cataloged as R136, energize the nebular glow and shape the spidery filaments. Around the Tarantula are other star forming regions with young star clusters, filaments, and blown-out bubble-shaped clouds. In fact, the frame includes the site of the closest supernova in modern times, SN 1987A, left of center. The rich field of view spans about 1 degree or 2 full moons, in the southern constellation Dorado. But were the Tarantula Nebula closer, say 1,500 light-years distant like the local star forming Orion Nebula, it would take up half the sky.   Still going on: Leonid Meteor Shower

Image credit: Barden Ridge Observatory
Creature Aurora Over Norway (2018-11-18)

It was Halloween and the sky looked like a creature. Exactly which creature, the astrophotographer was unsure but (possibly you can suggest one). Exactly what caused this  eerie apparition in 2013 was sure: one of the best auroral displays in recent years. This spectacular aurora had an unusually high degree of detail. Pictured here, the vivid green and purple  auroral colors are caused by high atmospheric oxygen and nitrogen reacting to a burst of incoming electrons.  Birch trees in Troms�, Norway formed an also eerie foreground. Recently, new photogenic auroras have accompanied new geomagnetic storms.

Image credit: Ole C. Salomonsen
(Arctic Light Photo)
Gibbous Moon beyond Swedish Mountain (2018-11-19)

This is a gibbous Moon. More Earthlings are familiar with a full moon, when the entire face of Luna is lit by the Sun, and a crescent moon, when only a sliver of the Moon's face is lit.  When more than half of the Moon is illuminated, though, but still short of full illumination, the phase is called gibbous.  Rarely seen in television and movies, gibbous moons are quite common in the actual night sky. The featured image was taken in J�mtland, Sweden near the end of last month.  That gibbous moon turned, in a few days, into a crescent moon, and then a new moon, then back to a crescent, and a few days ago back to gibbous.  And this same gibbous moon is visible again tonight, leading up to the Full Beaver Moon that occurs Friday night.  Setting up to capture a picturesque gibbous moonscape, the photographer was quite surprised to find an airplane, surely well in the foreground, appearing to fly past it.

Image credit: G�ran Strand
The Unexpected Trajectory of Interstellar Asteroid 'Oumuamua (2018-11-20)

Why is 'Oumuamua differing from its expected trajectory?  Last year, 1I/2017 U1 'Oumuamua became the first known asteroid from interstellar space to pass through our Solar System. Just over a year ago, this tumbling interstellar rock even passed rather close to the Earth. The asteroid's future path should have been easy to predict given standard gravity -- but 'Oumuamua's path has proven to be slightly different. In the featured animation, 'Oumuamua is shown approaching and exiting the vicinity of our Sun, with the expected gravitational and observed trajectories labelled. The leading natural hypothesis for this unexpected deviation is internal gas jets becoming active on the Sun-warmed asteroid -- but speculation and further computer simulations are ongoing. 'Oumuamua will never return, but modern sky monitors are expected to find and track similar interstellar asteroids within the next few years.
Swirls and Colors on Jupiter from Juno (2018-11-21)

What creates the colors in Jupiter's clouds? No one is sure.  The thick atmosphere of Jupiter is mostly hydrogen and helium, elements which are colorless at the low temperatures of the Jovian cloud tops. Which trace elements provide the colors remains a topic of research, although small amounts of ammonium hydrosulfide are one leading candidate.  What is clear from the featured color-enhanced image -- and many similar images -- is that lighter clouds are typically higher up than darker ones. Pictured, light clouds swirl around reddish regions toward the lower right, while they appear to cover over some darker domains on the upper right. The featured image was taken by the robotic Juno spacecraft during its 14th low pass over Jupiter earlier this year.  Juno continues in its looping elliptical orbit, swooping near the huge planet every 53 days and exploring a slightly different sector each time around.
Portrait of NGC 281 (2018-11-22)

Look through the cosmic cloud cataloged as NGC 281 and you might miss the stars of open cluster IC 1590. Still, formed within the nebula that cluster's young, massive stars ultimately power the pervasive nebular glow. The eye-catching shapes looming in this portrait of NGC 281 are sculpted dusty columns and dense Bok globules seen in silhouette, eroded by intense, energetic winds and radiation from the hot cluster stars. If they survive long enough, the dusty structures could also be sites of future star formation. Playfully called the Pacman Nebula because of its overall shape, NGC 281 is about 10,000 light-years away in the constellation Cassiopeia. This sharp composite image was made through narrow-band filters. It combines emission from the nebula's hydrogen and oxygen atoms to synthesize red, green, and blue colors. The scene spans well over 80 light-years at the estimated distance of NGC 281.

Image credit: Jeremiah Roth
Good Morning Leonid (2018-11-23)

On November 17, just an hour before sunrise, this bright and colorful meteor flashed through clear predawn skies. Above a sea of clouds this striking autumn morning's moment was captured from Hochblauen, a prominent 1165 meter high summit in southern Germany's Black Forest. Shining through the twilight, Sirius as well as the familiar stars of Orion are recognizable near the southwestern horizon, and the meteor seems headed right for the hunter's belt and sword. Still, as part of the annual Leonid meteor shower, the meteor trail does point back to the shower's radiant. The constellation Leo is high above the horizon and off the top left of the frame.

Image credit: Stephane Vetter
Shipwreck at Moonset (2018-11-24)

A crescent Moon is about to sink under the western horizon in this sea and night skyscape. The atmospheric photo was taken on September 11 from the desert shore along the Skeleton Coast of Namibia. So close to moonset, the moonlight is reddened and dimmed by the low, long line-of-sight across the Atlantic. But near the center of the frame Venus still shines brightly, its light reflected in calm ocean waters. The celestial beacon above the brilliant evening star is bright planet Jupiter. Namibia's Skeleton Coast was so named for the many seal and whale bones that were once strewn along the shoreline. In more recent times it's better known for shipwrecks.

Image credit: Vikas Chander
Phobos: Doomed Moon of Mars (2018-11-25)

This moon is doomed. Mars, the red planet named for the Roman god of war, has two tiny moons, Phobos and Deimos, whose names are derived from the Greek for Fear and Panic. The origin of the Martian moons is unknown, though, with a leading hypothesis holding that they are captured asteroids. The larger moon, at 25-kilometers across, is Phobos, and is indeed seen to be a cratered, asteroid-like object in this false-colored image mosaic taken by the robotic Viking 1 mission in 1978.  A recent analysis of the unusual long grooves seen on Phobos indicates that they may result from boulders rolling away from the giant impact that created the crater on the upper left: Stickney Crater.  Phobos orbits so close to Mars - about 5,800 kilometers above the surface compared to 400,000 kilometers for our Moon - that gravitational tidal forces are dragging it down. The ultimate result will be for Phobos to break up in orbit and then crash down onto the Martian surface in about 50 million years.  Well before that -- tomorrow, in fact, if everything goes according to plan -- NASA's robotic InSight lander will touch down on Mars and begin investigating its internal structure.   Latest: Insight to Land on Mars Tomorrow
Rocket Launch as Seen from the Space Station (2018-11-26)

Have you ever seen a rocket launch -- from space?  A close inspection of the featured time-lapse video will reveal a rocket rising to Earth orbit as seen from the International Space Station (ISS).  The Russian Soyuz-FG rocket was launched ten days ago from the Baikonur Cosmodrome in Kazakhstan, carrying a Progress MS-10 (also 71P) module to bring needed supplies to the ISS.  Highlights in the 90-second video (condensing about 15-minutes) include city lights and clouds visible on the Earth on the lower left, blue and gold bands of atmospheric airglow running diagonally across the center, and distant stars on the upper right that set behind the Earth. A lower stage can be seen falling back to Earth as the robotic supply ship fires its thrusters and begins to close on the ISS, a space laboratory that is celebrating its 20th anniversary this month. Currently, three astronauts live aboard the Earth-orbiting ISS, and conduct, among more practical duties, numerous science experiments that expand human knowledge and enable future commercial industry in low Earth orbit.    Latest: Insight to Land on Mars Today