Η Αστρονομική Εικόνα της Ημέρας από τη NASA
Nova V462 Lupi Now Visible
03/07/2025
If you know where to look, you can see a thermonuclear explosion from a white dwarf star. Possibly two. Such explosions are known as novas and the detonations are currently faintly visible with the unaided eye in Earth's southern hemisphere -- but are more easily seen with binoculars. Pictured, Nova Lupi 2025 (V462 Lupi) was captured toward the southern constellation of the Wolf (Lupus) last week near the central plane of our Milky Way galaxy. Nova Lupi 2025 was originally discovered on June 12 and peaked in brightness about a week later. Similarly, Nova Velorum 2025, toward the southern constellation of the Ship Sails (Vela), was discovered on June 25 and peaked a few days later. A nova somewhere in our Galaxy becomes briefly visible to the unaided eye only every year or two, so it is quite unusual to have two novas visible simultaneously. Meanwhile, humanity awaits even a different nova: T Coronae Borealis, which should become visible in northern skies and is expected to become even brighter.
Copyright: Matipon Tangmatitham (NARIT)
Προηγούμενες Αστρονομικές Εικόνες της Ημέρας από τη NASA
Spiral Galaxy NGC 6744
01/11/2024
Big, beautiful spiral galaxy NGC 6744 is nearly 175,000 light-years across, larger than our own Milky Way. It lies some 30 million light-years distant in the southern constellation Pavo but appears as only a faint smudge in the eyepiece of a small telescope. We see the disk of the nearby island universe tilted towards our line of sight in this remarkably deep and detailed galaxy portrait, a telescopic image that spans an area about the angular size of a full moon. In it, the giant galaxy's elongated yellowish core is dominated by the light from old, cool stars. Beyond the core, grand spiral arms are filled with young blue star clusters and speckled with pinkish star forming regions. An extended arm sweeps past smaller satellite galaxy NGC 6744A at the upper left. NGC 6744's galactic companion is reminiscent of the Milky Way's satellite galaxy the Large Magellanic Cloud.
Copyright: John Hayes
Rigel and the Witch Head Nebula
31/10/2024
By starlight, this eerie visage shines in the dark with a crooked profile evoking its popular name, the Witch Head Nebula. In fact, this entrancing telescopic portrait gives the impression that a witch has fixed her gaze on Orion's bright supergiant star Rigel. More formally known as IC 2118, the Witch Head Nebula spans about 50 light-years and is composed of interstellar dust grains reflecting Rigel's starlight. The color of the Witch Head Nebula is caused not only by Rigel's intense blue light, but because the dust grains scatter blue light more efficiently than red. The same physical process causes Earth's daytime sky to appear blue, although the scatterers in Earth's atmosphere are molecules of nitrogen and oxygen. Rigel and this dusty cosmic crone are about 800 light-years away. You may still see a few witches in your neighborhood tonight though, so have a safe and Happy Halloween!
Copyright: Simone Curzi
NGC 7635: The Bubble Nebula
30/10/2024
What created this huge space bubble? Blown by the wind from a star, this tantalizing, head-like apparition is cataloged as NGC 7635, but known simply as the Bubble Nebula. The featured striking view utilizes a long exposure to reveal the intricate details of this cosmic bubble and its environment. Although it looks delicate, the 10 light-year diameter bubble offers evidence of violent processes at work. Seen here above and right of the Bubble's center, a bright hot star is embedded in the nebula's reflecting dust. A fierce stellar wind and intense radiation from the star, which likely has a mass 10 to 20 times that of the Sun, has blasted out the structure of glowing gas against denser material in a surrounding molecular cloud. The intriguing Bubble Nebula lies a mere 11,000 light-years away toward the boastful constellation Cassiopeia. Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)
Copyright: Chad Leader
NGC 602: Stars Versus Pillars from Webb
29/10/2024
The stars are destroying the pillars. More specifically, some of the newly formed stars in the image center are emitting light so energetic that is evaporating the gas and dust in the surrounding pillars. Simultaneously, the pillars themselves are still trying to form new stars. The whole setting is the star cluster NGC 602, and this new vista was taken by the Webb Space Telescope in multiple infrared colors. In comparison, a roll-over image shows the same star cluster in visible light, taken previously by the Hubble Space Telescope. NGC 602 is located near the perimeter of the Small Magellanic Cloud (SMC), a small satellite galaxy of our Milky Way galaxy. At the estimated distance of the SMC, the featured picture spans about 200 light-years. A tantalizing assortment of background galaxies are also visible -- mostly around the edges -- that are at least hundreds of millions of light-years beyond.
Copyright: NASA
STEVE: A Glowing River over France
28/10/2024
Sometimes a river of hot gas flows over your head. In this case the river created a Strong Thermal Emission Velocity Enhancement (STEVE) that glowed bright red, white, and pink. Details of how STEVEs work remain a topic of research, but recent evidence holds that their glow results from a fast-moving river of hot ions flowing over a hundred kilometers up in the Earth's atmosphere: the ionosphere. The more expansive dull red glow might be related to the flowing STEVE, but alternatively might be a Stable Auroral Red (SAR) arc, a more general heat-related glow. The featured picture, taken earlier this month in Côte d'Opale, France, is a wide-angle digital composite made as the STEVE arc formed nearly overhead. Although the apparition lasted only a few minutes, this was long enough for the quick-thinking astrophotographer to get in the picture -- can you find him?
Copyright: Louis LEROUX-GÉRÉ
LDN 43: The Cosmic Bat Nebula
27/10/2024
What is the most spook-tacular nebula in the galaxy? One contender is LDN 43, which bears an astonishing resemblance to a vast cosmic bat flying amongst the stars on a dark Halloween night. Located about 1400 light years away in the constellation Ophiuchus, this molecular cloud is dense enough to block light not only from background stars, but from wisps of gas lit up by the nearby reflection nebula LBN 7. Far from being a harbinger of death, this 12-light year-long filament of gas and dust is actually a stellar nursery. Glowing with eerie light, the bat is lit up from inside by dense gaseous knots that have just formed young stars. Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)
Copyright: Mark Hanson and Mike Selby; Text: Michelle Thaller (NASA's GSFC)
Phantoms in Cassiopeia
26/10/2024
These brightly outlined flowing shapes look ghostly on a cosmic scale. A telescopic view toward the constellation Cassiopeia, the colorful 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. They are slowly disappearing though, 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 and lies just above the 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 hot star's ultraviolet radiation recombine with electrons. Farther from the star, IC 59 shows less H-alpha emission but more of the characteristic blue tint of dust reflected star light. The field of view spans over 1 degree or 10 light-years at the estimated distance of the interstellar apparitions.
Copyright: Christophe Vergnes
Globular Star Cluster NGC 6752
25/10/2024
Some 13,000 light-years away toward the southern constellation Pavo, the globular star cluster NGC 6752 roams the halo of our Milky Way galaxy. Over 10 billion years old, NGC 6752 follows clusters Omega Centauri, 47 Tucanae, and Messier 22 as the fourth brightest globular in planet Earth's night sky. It holds over 100 thousand stars in a sphere about 100 light-years in diameter. Telescopic explorations of NGC 6752 have found that a remarkable fraction of the stars near the cluster's core, are multiple star systems. They also reveal the presence of blue straggle stars, stars which appear to be too young and massive to exist in a cluster whose stars are all expected to be at least twice as old as the Sun. The blue stragglers are thought to be formed by star mergers and collisions in the dense stellar environment at the cluster's core. This sharp color composite also features the cluster's ancient red giant stars in yellowish hues. (Note: The bright, spiky blue star about 8 o'clock from the cluster center is a foreground star along the line-of-sight to NGC 6752)
Copyright: Massimo Di Fusco
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.