Η Αστρονομική Εικόνα της Ημέρας από τη NASA
RCW 86: Historical Supernova Remnant
24/07/2026
In 185 AD, Chinese astronomers recorded the appearance of a new star in the Nanmen asterism. That part of the sky is identified with part of the southern constellation Centaurus on modern star charts. In fact, the new star was reported to be visible to the naked-eye for months before it faded from view, and is now thought to be the earliest recorded supernova. In this 21st century telescopic image, the wispy outlines of a faint emission nebula recognized as the remnant of that historical stellar explosion can be traced against a starry background. The ragged but roughly circular extent of the nebula, cataloged as RCW 86, represents interstellar gas ionized by the supernova's still expanding shock wave. Space-based images indicate an abundance of the element iron in RCW 86 and the absence of a neutron star or pulsar within the remnant, suggesting that the original supernova was Type Ia. Unlike the core collapse supernova explosion of a massive star, a Type Ia supernova is a thermonuclear detonation on a white dwarf star that has accreted material from its companion in a binary star system. Near the plane of our Milky Way galaxy and larger than the full moon on the sky this supernova remnant is too faint to be seen by eye though. RCW 86 is some 8,000 light-years distant and around 100 light-years across.
Copyright: Chinese astronomers
Προηγούμενες Αστρονομικές Εικόνες της Ημέρας από τη NASA
Mars Marathon by Perseverance
27/06/2026
In this recent HiRISE view from the Mars Reconnaissance Orbiter, the little green dot indicated on the surface of the big Red Planet is the Perseverance Mars rover. Recorded on June 13, the car-sized, six-wheeled robot was imaged a day before completing a Martian marathon, traveling a total distance of 26.218 miles (42.195 kilometers) since it began exploring the surface of Mars. That equivalent marathon distance was achieved by Perseverance on its mission sol (Martian day) 1,890, after about 5 Earth years and 4 Earth months of driving. Perseverance is continuing to hunt for biosignatures. In the HiRISE image, the Mars rover's tracks can be seen leading to its location in an area west of its landing site in Jezero crater near an ancient river delta.
Copyright: NASA
Milky Way Urban Style
26/06/2026
In a cosmic vista you can never see, the Milky Way arcs through the night above Seoul, South Korea. Remarkably, this urban night skyscape reveals our galaxy's faintly luminous central region and dark obscuring dust clouds in spite of the brilliant city lights. To overcome the extreme light pollution of the metropolitan area and record faint cosmic details, an infrared filter was used to capture the night scene in a single exposure. While the filter transmits predominately infrared light, it still passes some visible light to give the scene a natural appearance. The view is from Seoul's Ttukseom Hangang Park, with the Han River and a well lit railway bridge across the foreground. The 123 story Lotte World Tower looms in the distance, the tallest building in South Korea.
Copyright: Shingoo Lee
Anticrepuscular Rays over Sicily
25/06/2026
The Sun has just set... in the opposite side of the sky. Pictured here are anticrepuscular rays apparently converging in the east in this image of the limestone plateau in the heart of the Hyblaean Mountains of southeastern Sicily, in Italy. How were these anticrepuscular rays formed, if the Sun wasn't there? After the Sun set (in the west, as usual) its light still illuminated a cloud higher up in the sky. Partially blocked by the cloud, the sunlight produced patterns of light and shadow, crossing the sky in parallel lines. Perspective makes it look like they converge in the east, in the same way that train tracks appear to meet in the distance. This effect can also happen at sunrise, only the directions are exchanged. In rare cases, both crepuscular and anticrepuscular rays can be seen at the same time.
Copyright: Marcella Giulia Pace Text: Cecilia Chirenti (NASA GSFC, UMCP, CRESST II)
M27: The Dumbbell Nebula
22/06/2026
Is this what will become of our Sun? Quite possibly. The first hint of our Sun's future was discovered inadvertently in 1764. At that time, Charles Messier was compiling a list of diffuse objects not to be confused with comets. The 27th object on Messier's list, now known as M27 or the Dumbbell Nebula, is a planetary nebula, one of the brightest planetary nebulas on the sky and visible with binoculars toward the constellation of the Fox (Vulpecula). It takes light about 1000 years to reach us from M27, featured here in colors enhanced by red for hydrogen and blue for oxygen. We now know that in about 6 billion years, our Sun will shed its outer gases into a planetary nebula like M27, while its remaining center will become an X-ray hot white dwarf star. Understanding the physics and significance of M27 was well beyond 18th century science, though. Even today, many things remain mysterious about planetary nebulas, including how their intricate shapes are created.
Copyright: Francesco Antonucci
Starry Night II
19/06/2026
Does this scene look familiar? It is a modern recreation of the famous painting Starry Night by Vincent van Gogh. Both the image and the painting depict a tall tree on the left, a crescent moon on the upper right, the planet Venus just to the right of the tree, a foreground horizon rising from left to right, and clouds above the horizon. Differences include that the photograph was taken in mid-April earlier this year in Cascavel, Brazil, while the painting was composed in Saint-Rémy-de-Provence, France, in 1889. The original Starry Night is considered by many to be one of the three most famous paintings in the world today and a statement about the wonders of the night sky. Today is (roughly) the anniversary of the morning that van Gogh saw the sky that he later painted in his version of Starry Night. Night Sky Jigsaw: Astronomy Puzzle of the Day
Copyright: Rodrigo Guerra, Original Painting: Vincent van Gogh
Longmore 8: The Hamster Wheel Nebula
17/06/2026
How did a hamster wheel get into space? The Hamster Wheel Nebula (Longmore 8) was discovered by Andrew Longmore in 1976 as a part of a larger survey of the southern sky. This survey employed several improvements in photographic technology, including the use of highly sensitive film, to capture deeper and fainter objects on plates that were examined by eye and catalogued. The featured image, taken at Observatorio El Sauce in Chile, depicts an intricate wheel structure of glowing hydrogen that was thrown out into space by a dying star and ionized by the leftover white dwarf. This structure was barely visible on the original plate, emphasizing the power of modern telescopes and cameras. Two opposing clumps of red hydrogen gas encased in the blue veil of ionized oxygen hint at the presence of a companion to the bright white dwarf at the wheel’s center!
Copyright: Mazlin, Parker, Forman, Magill, Hanson Text: Keighley Rockcliffe (NASA GSFC, UMBC CSST, CRESST II)
Moons, Rings, Shadows, Clouds: Saturn (Cassini)
16/06/2026
While cruising around Saturn, be on the lookout for picturesque arrangements of moons, rings, and shadows. One such striking sight occurred in 2005 and was captured by the then Saturn-orbiting Cassini spacecraft. In the featured image, moons Mimas (left) and Tethys (right) are visible on either side of Saturn's thin rings, which are seen nearly edge-on. Across the top of Saturn are dark shadows of the wide rings, exhibiting their impressive complexity. The violet-light image brings up the texture of the backdrop: Saturn's clouds. Cassini orbited Saturn from 2004 until mid-2017, when the robotic spacecraft was directed to dive into Saturn to keep it from contaminating any moons. Explore the Universe: Random APOD Generator
Copyright: NASA
Triple Shockwave from Sun Crossing Rocket
15/06/2026
What's happening to this Sun-crossing rocket? The SpaceX Falcon 9 rocket, visible on the upper left, launched only about one minute before this amazing image was captured. As it rose to low Earth orbit from Cape Canaveral, Florida, USA, in late May, the rocket became supersonic before it crossed the disk of the distant Sun -- from the perspective of the well-placed photographer. The spacecraft's high speed caused bow-shaped compressed-air shockwaves to form across leading surfaces, with at least three visible even outside the Sun's disk because they refract sunlight. The trailing exhaust caused turbulence visible on the lower right. None of this was damaging to the robotic Starlink 10-53 mission, which delivered 29 communications satellites to low Earth orbit as planned. And if that isn't amazing enough - the Sun had spots! Sky Surprise: What picture did APOD feature on your birthday? (after 1995)
Copyright: John Winkopp (WAI Media)
Η Αστρονομική Εικόνα της Ημέρας από τη NASA (NASA Astronomy Picture of the Day) είναι μια δωρεάν υπηρεσία που παρέχει καθημερινά μια εντυπωσιακή εικόνα από το σύμπαν, την λήψη της οποίας έχει πραγματοποιήσει κάποιος από τους αστρονόμους της NASA ή από κάποιον από τους δορυφόρους ή τα τηλεσκόπια που η NASA λειτουργεί. Οι εικόνες που εμφανίζονται καλύπτουν μια ευρεία γκάμα από θέματα, συμπεριλαμβανομένων των αστερισμών, των γαλαξιών, των πλανητικών συστημάτων, των κομητών, των αστρικών σωμάτων και των παρατηρητηρίων. Κάθε εικόνα συνοδεύεται από μια σύντομη εξήγηση και πληροφορίες σχετικά με το τι παρατηρείται στην εικόνα.