Large Scale Structure of the UniverseThis is a map of the universe. The Dark Energy Spectroscopic Instrument (DESI) at Kitt Peak National Observatory, Arizona, has finished its five-year survey. It observed more than 47 million galaxies and quasars and created a 3D map centered on the Earth. Today's featured image shows a thin slice of these data: the black gaps indicate where our Galaxy obscures distant objects. The feathery web in the inset shows the large scale structure of the universe. Light of the most distant galaxies shown here travelled for 11 billion years to reach the Earth. Galaxies cluster throughout cosmic history under the competing influences of gravity and dark energy, responsible for the accelerated expansion of the universe. Analysis of early DESI results hinted at the possibility that dark energy, described as a cosmological constant by Albert Einstein, may not be constant after all. But we still have to wait for the analysis of the now complete dataset. The nature of dark energy is the biggest mystery of cosmology.2026-04-23
More Details Past Days
Earthset with an iPhoneWhat does it mean for the Earth to set? Artemis II Commander Reid Wiseman gave us another spectacular view of Earth from their historic flyby of the Moon. Commander Wiseman's video, taken with an iPhone at 8x zoom, shows our entire planet gradually blocked from view by the Moon. On the Earth, the 24-hour planetary rotation causes the Sun to set below your horizon every night. However, on Artemis II the Earthset was caused not by the Moon’s rotation but by the spacecraft moving behind the Moon (at about 55 seconds in this video). Once rare, views of Earth are now taken many times a day from many spacecraft, including NASA’s SWOT (Surface Water and Ocean Topography) satellite tracking freshwater resources and USGS Landsat 8 and 9 satellites supporting water management for farmers, for example. Space agencies around our home planet now work together to provide unique and ever-improving views of our Earth. Celebrate: Earth Day2026-04-22
More Details © Angel Fux
Three Sky Arches over Snowy AlpsWhy are there three arches across the sky instead of two? Last month, after being dropped off by a helicopter at a high mountain peak in the Alps near the Swiss Italian border, an adventurous astrophotographer expected two arches of our Milky Way galaxy to be visible during the night. These were the inner arch looking in toward the center of our galaxy on the left, visible just before sunrise, and the outer arch on the right visible just after sunset. But there were three arches. The surprised astrophotographer soon realized that the sky was so dark that an entire arc of faint zodiacal light was also noticeable -- sunlight scattered by inner Solar System dust. And it artfully connected the two Milky Way arches! The next morning a helicopter picked the astrophotographer back up, and after 40 hours of processing and combining that night's images, the featured triple-arch 360-degree panorama resulted. Jigsaw Vistas: Astronomy Puzzle of the Day2026-04-21
More Details © Basudeb Chakrabarti &
Samit Saha
Comet R3 PanSTARRS over a Himalayan ValleyThe best way to see comet R3 PanSTARRS’s long tail is with a camera. This week, the recently brightened comet appears in northern skies to the east just before dawn, but is only barely visible to the unaided eye. The many-degree ion tail captured on long duration camera exposures is not unusual for a comet - it is primarily due to the Earth's nearly sideways view of the tail as it points away from the Sun. In the featured image taken last week, Comet C/2025 R3 (PanSTARRS) showed off its flowing tail through a valley between two peaks in the Himalayan mountains of India. The comet passed its closest to the Sun yesterday. As it nears its closest approach to Earth next week, a bushy dust tail may become visible. The comet is slowly moving out of northern skies and by the end of the month will be visible after sunset in southern skies as it fades and leaves our Solar System. Growing Gallery: Comet R3 PanSTARRS in 20262026-04-20
More Details © Miguel Claro
(TWAN,
Dark Sky Alqueva)
Eye on the Milky WayHave you ever had stars in your eyes? It appears that the eye on the left does, and moreover, it appears to be gazing at even more stars. The featured 27-frame mosaic was taken in 2019 from Ojas de Salar in the Atacama Desert of Chile. The eye is actually a small lagoon captured reflecting the dark night sky as the Milky Way Galaxy arched overhead. The seemingly smooth band of the Milky Way is really composed of billions of stars, but decorated with filaments of light-absorbing dust and red-glowing nebulas. Additionally, both Jupiter (slightly left the galactic arch) and Saturn (slightly to the right) are visible. The lights of small towns dot the unusual vertical horizon. The rocky terrain around the lagoon appears to some more like the surface of Mars than our Earth. Sky Surprise: What picture did APOD feature on your birthday? (after 1995)2026-04-19
More Details © Luc Perrot
PanSTARRS and PlanetsNear the eastern horizon before sunrise, Comet C/2025 R3 PanSTARRS is getting brighter. Readily visible in binoculars and small telescopes, the comet may be just on the verge of naked-eye visibility from dark sky sites. Though it was not quite apparent to the eye, PanSTARRS is still easy to spot in this camera image taken on April 16. In the view from a volcanic peak overlooking France's Reunion Island, planet Earth, the comet shares eastern predawn skies with naked-eye planets Mars and Mercury and fainter Neptune. Saturn is hiding behind the low cloudbank that doesn't quite hide an old crescent Moon. This is a good weekend for northern hemisphere comet watchers to try to catch PanSTARRS an hour or so before sunrise, as the comet grows brighter approaching its perihelion on April 19. On April 26 the comet makes its closest approach to our fair planet but by then will be difficult to see in the solar glare. Good views of this comet PanSTARRS in late April and early May will be from the southern hemisphere.2026-04-18
More Details © Arnaud Malleval
M82: Starburst Galaxy with a SuperwindMessier 82 is a starburst galaxy with a superwind. In fact, through supernova explosions and powerful winds from massive stars, the burst of star formation in M82 is driving a prodigious outflow. Evidence for the superwind from the galaxy's central regions is clear in the sharp telescopic portrait. The composite image includes 33 hours of narrowband data, highlighting emission from long outflow filaments of atomic hydrogen gas in reddish hues. Some of the gas in the superwind, enriched in heavy elements forged in the massive stars, will eventually escape into intergalactic space. Triggered by a close encounter with nearby large galaxy M81, the furious burst of star formation in M82 should last about 100 million years or so. Also known as the Cigar Galaxy for its elongated visual appearance, M82 is about 30,000 light-years across. It lies 12 million light-years away near the northern boundary of Ursa Major.2026-04-17
More Details © Kiko Fairbairn
South Celestial TreeIf you live in the northern hemisphere, you may have learned how to locate the North Star, Polaris, in the night sky. It can be used to find north, and it approximately marks the northern celestial pole. If you live in the southern hemisphere, there is no bright star marking the southern celestial pole, but the Southern Cross can be used to find south. The featured image was taken in Padre Bernardo (GO), Brazil. It shows the apparent motion of the stars around the apparently empty southern celestial pole over 2 hours, on August 20, 2018. Each star takes about 24 hours to make a complete turn around the pole in the sky. Padre Bernardo is located in the Cerrado region, a tropical savanna that occupies most of central Brazil and supports rich biodiversity. The barren branch that apparently supports this sky wheel of rotating stars is a common sight there in the dry season during the southern winter.2026-04-16
More Details © Sébastien Borie
Text:
Keighley Rockcliffe
(NASA
GSFC,
UMBC CSST,
CRESST II)
The ISS Transits the MoonNope, that is not an alien spaceship landing on the Moon! This is an image of the International Space Station (ISS) as it begins to transit in front of the Moon. The ISS is in low-Earth orbit (LEO) where it wizzes around the Earth every 90 minutes. Orbiting the Earth 16 times per day for 25 years, the ISS has photobombed many familiar celestial objects including Venus, Mars, Saturn, and the Sun. Thousands of experiments led by researchers from over one hundred countries have been conducted on the ISS. Growing protein crystals in low gravity was one of the first experiments onboard the ISS and continues to contribute to new medical treatments. ISS astronauts study plant growth, water recycling, human health, and more to support the Artemis missions which will take humans farther than they’ve ever gone before. Next time you are out and about at night, try to spot the ISS zooming across the sky!2026-04-15
More Details © Haythem Hamdi
The Long Wispy Tail of Comet R3 (PanSTARRS)Why does Comet R3 (PanSTARRS) have a wispy tail? The newest bright member of the inner Solar System, Comet C/2025 R3 (PanSTARRS) is already extending an impressive stream of glowing gas. This tail starts from an unseen central nucleus of dirty ice that is likely a few kilometers across. The nucleus is warmed by the Sun and emits a cloud of neutral gas into a coma that glows light green. Nuclear gas ionized by energetic sunlight is pushed away from the Sun by the solar wind into an ion tail that glows light blue. The wispy nature of the ion tail is caused by the constantly changing structure of the solar wind. Pictured from Rhode Island, USA two days ago, Comet R3 (PanSTARRS) shows off a many-degree ion tail. Comet R3 (PanSTARRS) is best seen before dawn from northern skies for another 10 days, after which it will be best visible from southern skies. Growing Gallery: Comet R3 in 20262026-04-14
More Details 
NGC 602 and BeyondThe clouds may look like an oyster, and the stars like pearls, but look beyond. 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 featured picture spans about 200 light-years, but a tantalizing assortment of background galaxies are also visible in this sharp multi-colored view. The background galaxies are hundreds of millions of light-years or more beyond NGC 602. Sky Surprise: What picture did APOD feature on your birthday? (after 1995)2026-04-13
More Details © José Rodrigues
Comet R3 (PanSTARRS) BrightensComet R3 is brightening rapidly -- will it survive? C/2025 R3 (PanSTARRS) has been slowly brightening and extending an ion tail since its discovery last year. This shedding mountain of dirty ice puts on its best sky show this month, though, because it passes its closest to both the Sun (April 19) and the Earth (April 25). The featured image, showing R3 already sporting a tail extending over 10 degrees, was taken two nights ago from Sion, Switzerland with the big mountain Bietschhorn on the left. Comet R3 will be visible during mid-April before sunrise. Although the future brightness of any comet is hard to predict, the brightness of R3 makes it already a good camera comet and it may become visible to the unaided eye in the next week. Comet R3's physical future is also unknown because, like Comet A1 (MAPS) earlier this month, it may disintegrate when it passes its closest to the Sun. Or it may live to leave the Solar System. Growing Gallery: Comet R3 in 20262026-04-12
More Details 
Artemis II: Flight Day 6On flight day 6 (April 6) the Artemis II mission achieved a historic lunar flyby. Rounding the lunar far side, the deep space maneuver marked humanity's first venture to the Moon since Apollo 17 in 1972. The Orion spacecraft Integrity reached a maximum distance of nearly 407,000 kilometers, and the Artemis II crew, Reid Wiseman, Victor Glover, and Christina Koch, and Jeremy Hansen, set the record for the farthest distance from Earth traveled by any human since the Apollo 13 crew in 1970. From behind the Moon on flight day 6, a solar array wing camera recorded this space age selfie, framing the spacecraft and lunar far side. Planet Earth, home to the Artemis II crew, is the small, bright crescent beyond the lunar limb. The crew safely returned home on Artemis II mission flight day 10. Artemis II: Splashdown2026-04-11
More Details © Mike Selby
Exploring the AntennaeSome 60 million light-years away in the southerly constellation Corvus, two large galaxies are colliding. Stars in the two galaxies, cataloged as NGC 4038 and NGC 4039, very rarely collide in the course of the ponderous cataclysm that lasts for hundreds of millions of years. But the galaxies' large clouds of molecular gas and dust often do, triggering furious episodes of star formation near the center of the cosmic wreckage. Spanning over 50 thousand light-years, this stunning telescopic frame also reveals new star clusters and matter flung far from the scene of the accident by gravitational tidal forces. The remarkably sharp ground-based image follows the faint tidal tails and distant background galaxies in the field of view. The suggestive overall visual appearance of the extended arcing structures gives the galaxy pair, also known as Arp 244, its popular name - The Antennae. Artemis II: Splashdown2026-04-10
More Details Destruction of Comet C/2026 A1 (MAPS)As the crew of Artemis II travelled towards the Moon this week, Comet C/2026 A1 (MAPS) was expected to have its closest approach to the Sun on Monday. At this point, comet and Sun would be closer than half the distance separating the Earth and Moon. The comet did not survive; the featured video was made with 40 hours of data and shows the comet plunging toward the Sun, like a moth to a flame. Observing the comet so close to our bright star requires a coronagraph, an instrument that blocks the Sun and is used for studies of its corona. This composite video combines, starting from the outside, views from: the wider angle coronagraph (blue) and the narrower angle coronagraph (red), both on NASA's Solar and Heliospheric Observatory, and NASA's Solar Dynamics Observatory (black). We can see the comet approaching the sun, stretching, disappearing behind the coronagraph's occulting disk and reappearing as a cloud of debris that dissipates.2026-04-09
More Details 
EarthsetAnd to all of you down there on Earth and around Earth, we love you, from the Moon. We will see you on the other side, said Artemis II pilot Victor Glover on
April 6th at 6:44pm ET
as 8.3 billion minus four people and one Earth
set
below the Moon's horizon. The Orion spacecraft, Integrity, then traveled behind the Moon as part of its seven-hour lunar flyby.
The crew characterized
never-before-seen regions of
the far side of the Moon,
which is
puzzlingly less volcanically active
than the near side. New observations of
crater peaks, floors, terraces, and rings
preserved on the lunar surface will
help piece together the impact history of the Solar System.
Among many other surface characterizations, the crew observed one of the Moon's best-preserved basins,
the Orientale basin,
and identified
two new craters.
As
Earth rose
above the Moon’s horizon and Integrity began its return home, Artemis II mission specialist Christina Koch powerfully summarized humanity’s grander mission: ...we will always choose Earth. We will always choose each other.2026-04-08
More Details © Rabeea Alkuwari
IC 4592: The Blue Horsehead Reflection NebulaDo 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 reflection nebula IC 4592. Reflection nebulas are made up of very fine dust that normally appears dark but can look quite blue when reflecting the visible 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 just below the image center. The featured picture was taken from Sawda Natheel in Qatar. Jigsaw Nebula: Astronomy Puzzle of the Day2026-04-07
More Details The Path of Artemis IIWhy doesn't Artemis II land on the Moon? The main reason is that Artemis II is primarily a test mission designed to make a future Artemis missions -- which will land humans on the Moon -- better prepared. Similarly, NASA's Apollo 8 and Apollo 10 went right near the Moon as tests before Apollo 11 -- which landed. As the trajectory in the featured animated video shows, Artemis II will loop around both the Earth and the Moon before returning to the Earth about 10 days after launch. The Artemis II mission will take humans outside the Earth's magnetosphere for the first time since the Apollo missions 50 years ago. In the video, particles from the solar wind are shown as streaks, while the Earth's reacting magnetosphere is shown in flickering green. The Earth's magnetosphere is important in deflecting powerful particles arriving from the Sun as well as creating picturesque auroras visible from the Earth's surface. Explore the Universe: Random APOD Generator2026-04-06
More Details © AAO ITSO Office,
Gemini Obs./AURA &
T. A. Rector
(U. Alaska Anchorage)
NGC 3310: A Starburst Spiral GalaxyThe party is still going on in spiral galaxy NGC 3310. Roughly 100 million years ago, NGC 3310 likely collided with a smaller galaxy causing the large spiral galaxy to light up with a tremendous burst of star formation. The changing gravity during the collision created density waves that compressed existing clouds of gas and triggered the star-forming party. The featured image from the Gemini North Telescope shows the galaxy in great detail, color-coded so that pink highlights gas while white and blue highlight stars. Some of the star clusters in the galaxy are quite young, indicating that starburst galaxies may remain in star-burst mode for quite some time. NGC 3310 spans about 50,000 light years, lies about 50 million light years away, and is visible with a small telescope towards the constellation of Great Bear Ursa Major.2026-04-05
More Details 
Hello WorldFrom pole to pole our fair planet is captured in this snapshot from space, an evocative image from a window of the Orion spacecraft Integrity. From the spacecraft's perspective the Sun is moving behind Earth's bright limb along the lower right. Africa and the Iberian peninsula are in view on the pale blue planet's surface, while aurorae crown Earth's south and north poles at top right and bottom left. Commander Reid Wiseman took the historic picture on Artemis II mission flight day 2 (April 2), after the completion of the planned translunar injection burn. That burn boosted the spacecraft out of Earth orbit, sending Integrity and crew on a trajectory that will take them around the Moon and back again. That's a journey humans last made over 50 years ago. (Editor's note: Venus is photobombing Wiseman's historic pic. Currently appearing in our western skies after sunset, the inner planet is in the frame below and right of Earth's bright limb, immersed in a faint band of zodiacal light.)2026-04-04
More Details © Carl Knox
Caught in the Web: Visualization of a Black Hole Merger in the Tarantula NebulaHow can we see what is invisible? Black holes are not easy to see in the dark cosmic night, but astronomers can find them by analyzing their gravitational effects on matter, light and spacetime. The featured image shows an illustration that combines a simulation of a black hole binary system in its final "death-dance" with an astrophotography image of the Tarantula Nebula in the background. Even though black holes don't emit light, they distort the path of light rays, acting like a gravitational lens. As a result, the nebula appears extremely distorted, forming Einstein rings and multiple images. Tarantula Nebula lies in the Large Magellanic Cloud, a dwarf galaxy that is one of the satellite galaxies of the Milky Way, 160,000 light-years away. That is more than 1,000 times closer than any of the binary black hole mergers detected so far. We'll probably never detect a merger so close to home!2026-04-03
More Details © NASA/Bill Ingalls;
Text: Ogetay Kayali
(MTU)
Liftoff! Returning to the MoonWe are one small step closer to returning to the Moon. A new chapter in human exploration began yesterday when NASA's Artemis II launched aboard the Space Launch System (SLS) from Kennedy Space Center. Carrying four astronauts, the Orion spacecraft's planned lunar flyby will be the first in over half a century. This historic test flight, echoing the legacy of Apollo while pushing beyond it, will carry its crew farther from Earth than any humans since 1972, looping around the Moon before returning home. During the approximately ten-day journey, Orion's systems--from life support to navigation--will be tested in deep space, while astronauts observe the lunar surface, including shadowed regions of the far side rarely seen with such perspective. After looping around the Moon, the astronauts will return to Earth, ending their journey with a Pacific Ocean splashdown.2026-04-02
More Details