Η Αστρονομική Εικόνα της Ημέρας από τη NASA
Gemini Meteors over Snow Capped Mountains
15/12/2025
Where are all of these meteors coming from? In terms of direction on the sky, the pointed answer is the constellation of Gemini. That is why the major meteor shower in December is known as the Geminids -- because shower meteors all appear to come from a radiant toward Gemini. Three dimensionally, however, sand-sized debris expelled from the unusual asteroid 3200 Phaethon follows a well-defined orbit about our Sun, and the part of the orbit that approaches Earth is superposed in front of the constellation of Gemini. Therefore, when Earth crosses this orbit, the radiant point of falling debris appears in Gemini. Featured here is a composite of many images taken over the past few days through dark skies from Slovakia and capturing the snow-covered peaks of the Belianske Tatra mountains Numerous bright meteor streaks from the Geminids meteor shower are visible. Orion is visible above the horizon, while the bright star nearest the radiant is Castor. APOD Review: RJN's Night Sky Network Lecture
Copyright: Tomáš Slovinský
Προηγούμενες Αστρονομικές Εικόνες της Ημέρας από τη NASA
NGC 6072: A Complex Planetary Nebula from Webb
05/08/2025
Why is this nebula so complex? The Webb Space Telescope has imaged a nebula in great detail that is thought to have emerged from a Sun-like star. NGC 6072 has been resolved into one of the more unusual and complex examples of planetary nebula. The featured image is in infrared light with the red color highlighting cool hydrogen gas. Study of previous images of NGC 6072 indicated several likely outflows and two disks inside the jumbled gas, while the new Webb image resolves new features likely including one disk's edge protruding on the central left. A leading origin hypothesis holds that the nebula's complexity is caused or enhanced by multiple outbursts from a star in a multi-star system near the center.
Copyright: NASA
Blue Arcs Toward Andromeda
04/08/2025
What are these gigantic blue arcs near the Andromeda Galaxy (M31)? Discovered in 2022 by amateur astronomers, the faint arcs -- dubbed SDSO 1 -- span nearly the same angular size as M31 itself. At first, their origin was a mystery: are they actually near the Andromeda Galaxy, or alternatively near to our Sun? Now, over 550 hours of combined exposure and a collaboration between amateur and professional astronomers has revealed strong evidence for their true nature: SDSO 1 is not intergalactic, but a new class of planetary nebula within our galaxy. Dubbed a Ghost Planetary Nebula (GPN), SDSO 1 is the first recognized member of a new subclass of faded planetary nebulas, along with seven others also recently identified. Shown in blue are extremely faint oxygen emission from the shock waves, while the surrounding red is a hydrogen-emitting trail that indicates the GPN's age.
Copyright: Ogle et al.
Milky Way and Exploding Meteor
03/08/2025
In about a week the Perseid Meteor Shower will reach its maximum. Grains of icy rock will streak across the sky as they evaporate during entry into Earth's atmosphere. These grains were shed from Comet Swift-Tuttle. The Perseids result from the annual crossing of the Earth through Comet Swift-Tuttle's orbit, and are typically the most active meteor shower of the year. Although it is hard to predict the level of activity in any meteor shower, in a clear dark sky an observer might see a meteor a minute. This year's Perseids peak just a few days after full moon, and so some faint meteors will be lost to the lunar skyglow. Meteor showers in general are best seen from a relaxing position, away from lights. Featured here is a meteor caught exploding during the 2015 Perseids above Austria next to the central band of our Milky Way Galaxy.
Copyright: Andre van der Hoeven
Fireflies, Meteors, and Milky Way
02/08/2025
Taken on July 29 and July 30, a registered and stacked series of exposures creates this dreamlike view of a northern summer night. Multiple firefly flashes streak across the foreground as the luminous Milky Way arcs above the horizon in the Sierra de Órganos national park of central Mexico, The collection of bright streaks aligned across the sky toward the upper left in the timelapse image are Delta Aquariid meteors. Currently active, the annual Delta Aquarid meteor shower shares August nights though, overlapping with the better-known Perseid meteor shower. This year that makes post-midnight, mostly moonless skies in early August very popular with late night skygazers. How can you tell a Delta Aquariid from a Perseid meteor? The streaks of Perseid meteors can be traced back to an apparent radiant in the constellation Perseus. Delta Aquariids appear to emerge from the more southerly constellation Aquarius, beyond the top left of this frame. Of course, the bioluminescent flashes of fireflies are common too on these northern summer nights. But how can you tell a firefly from a meteor? Just try to catch one.
Copyright: Daniel Korona
Small Dark Nebula
01/08/2025
A small, dark, nebula looks isolated near the center of this telescopic close-up. The wedge-shaped cosmic cloudlet lies within a relatively crowded region of space though. About 7,000 light-years distant and filled with glowing gas and an embedded cluster of young stars, the region is known as M16 or the Eagle Nebula. Hubble's iconic images of the Eagle Nebula include the famous star-forming Pillars of Creation, towering structures of interstellar gas and dust 4 to 5 light-years long. But this small dark nebula, known to some as a Bok globule, is a fraction of a light-year across. The Bok globule stands out in silhouette against the expansive background of M16's diffuse glow. Found scattered within emission nebulae and star clusters, Bok globules are small interstellar clouds of cold molecular gas and obscuring dust that also form stars within their dense, collapsing cores.
Copyright: Peter Bresseler
Supernova 2025rbs in NGC 7331
31/07/2025
A long time ago in a galaxy 50 million light-years away, a star exploded. Light from that supernova was first detected by telescopes on planet Earth on July 14th though, and the extragalactic transient is now known to astronomers as supernova 2025rbs. Presently the brightest supernova in planet Earth's sky, 2025rbs is a Type Ia supernova, likely caused by the thermonuclear detonation of a white dwarf star that accreted material from a companion in a binary star system. Type Ia supernovae are used as standard candles to establish the distance scale of the universe. The host galaxy of 2025rbs is NGC 7331. Itself a bright spiral galaxy in the northern constellation Pegasus, NGC 7331 is often touted as an analog to our own Milky Way.
Copyright: NASA
Coronal Loops on the Sun
30/07/2025
Our Sun frequently erupts in loops. Hot solar plasma jumps off the Sun's surface into prominences, with the most common type of prominence being a simple loop. The loop shape originates from the Sun's magnetic field, which is traced by spiraling electrons and protons. Many loops into the Sun's lower corona are large enough to envelop the Earth and are stable enough to last days. They commonly occur near active regions that also include dark sunspots. The featured panel shows four loops, each of which was captured near the Sun's edge during 2024 and 2025. The images were taken by a personal telescope in Mantova, Italy and in a very specific color of light emitted primarily by hydrogen. Some solar prominences suddenly break open and eject particles into the Solar System, setting up a space weather sequence that can affect the skies and wires of Earth. Jigsaw Universe: Astronomy Puzzle of the Day
Copyright: Andrea Vanoni
A Helix Nebula Deep Field
29/07/2025
Is the Helix Nebula looking at you? No, not in any biological sense, but it does look quite like an eye. The Helix Nebula is so named because it also appears that you are looking down the axis of a helix. In actuality, it is now understood to have a surprisingly complex geometry, including radial filaments and extended outer loops. The Helix Nebula (aka NGC 7293) is one of brightest and closest examples of a planetary nebula, a gas cloud created at the end of the life of a Sun-like star. The remnant central stellar core, destined to become a white dwarf star, glows in light so energetic it causes the previously expelled gas to fluoresce. The featured picture, taken in red, green, and blue but highlighted by light emitted primarily by hydrogen was created from 12 hours of exposure through a personal telescope located in Greece. A close-up of the inner edge of the Helix Nebula shows complex gas knots the origin of which are still being researched. Portal Universe: Random APOD Generator
Copyright: George Chatzifrantzis
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.