Η Αστρονομική Εικόνα της Ημέρας από τη NASA
Star Trails over One-Mile Radio Telescope
13/09/2025
The steerable 60 foot diameter dish antenna of the One-Mile Telescope at Mullard Radio Astronomy Observatory, Cambridge, UK, is pointing skyward in this evocative night-skyscape. To capture the dramatic scene, consecutive 30 second exposures were recorded over a period of 90 minutes. Combined, the exposures reveal a background of gracefully arcing star trails that reflect planet Earth's daily rotation on its axis. The North Celestial Pole, the extension of Earth's axis of rotation into space, points near Polaris, the North Star. That's the bright star that creates the short trail near the center of the concentric arcs. But the historic One-Mile Telescope array also relied on planet Earth's rotation to operate. Exploring the universe at radio wavelengths, it was the first radio telescope to use Earth-rotation aperture synthesis. That technique uses the rotation of the Earth to change the relative orientation of the telescope array and celestial radio sources to create radio maps of the sky at a resolution better than that of the human eye.
Copyright: Joao Yordanov Serralheiro
Προηγούμενες Αστρονομικές Εικόνες της Ημέρας από τη NASA
Comet Tsuchinshan-ATLAS Flys Away
19/10/2024
These six panels follow daily apparitions of comet C/2023 A3 Tsuchinshan-ATLAS as it moved away from our fair planet during the past week. The images were taken with the same camera and lens at the indicated dates and locations from California, planet Earth. At far right on October 12 the visitor from the distant Oort cloud was near its closest approach, some 70 million kilometers (about 4 light-minutes) away. Its bright coma and long dust tail were close on the sky to the setting Sun but still easy to spot against a bright western horizon. Over the following days, the outbound comet steadily climbs above the ecliptic and north into the darker western evening sky, but begins to fade from view. Crossing the Earth's orbital plane around October 14, Tsuchinshan-ATLAS exhibits a noticeable antitail extended toward the western horizon. Higher in the evening sky at sunset by October 17 (far left) the comet has faded and reached a distance of around 77 million kilometers from planet Earth. Hopefully you enjoyed some of Tsuchinshan-ATLAS's bid to become the best comet of 2024. This comet's initial orbital period estimates were a mere 80,000 years, but in fact it may never return to the inner Solar System. Growing Gallery: Comet Tsuchinshan-ATLAS in 2024
Copyright: Xingyang Cai
Most of Comet Tsuchinshan-ATLAS
18/10/2024
On October 14 it was hard to capture a full view of Comet C/2023 A3 Tsuchinshan-ATLAS. Taken after the comet's closest approach to our fair planet, this evening skyview almost does though. With two telephoto frames combined, the image stretches about 26 degrees across the sky from top to bottom, looking west from Gates Pass, Tucson, Arizona. Comet watchers that night could even identify globular star cluster M5 and the faint apparition of periodic comet 13P Olbers near the long the path of Tsuchinshan-ATLAS's whitish dust tail above the bright comet's coma. Due to perspective as the Earth is crossing the comet's orbital plane, Tsuchinshan-ATLAS also has a pronounced antitail. The antitail is composed of dust previously released and fanning out away from the Sun along the comet's orbit, visible as a needle-like extension below the bright coma toward the rugged western horizon. Growing Gallery: Comet Tsuchinshan-ATLAS in 2024
Copyright: Adam Block
The Clipper and the Comet
17/10/2024
NASA's Europa Clipper is now headed toward an ocean world beyond Earth. The large spacecraft is tucked into the payload fairing atop the Falcon Heavy rocket in this photo, taken at Kennedy Space Center the day before the mission's successful October 14 launch. Europa Clipper's interplanetary voyage will first take it to Mars, then back to Earth, and then on to Jupiter on gravity assist trajectories that will allow it to enter orbit around Jupiter in April 2030. Once orbiting Jupiter, the spacecraft will fly past Europa 49 times, exploring a Jovian moon with a global subsurface ocean that may have conditions to support life. Posing in the background next to the floodlit rocket is Comet Tsuchinsan-ATLAS, about a day after the comet's closest approach to Earth. A current darling of evening skies, the naked-eye comet is a vistor from the distant Oort cloud Growing Gallery: Comet Tsuchinshan-ATLAS in 2024
Copyright: Ben Cooper
Colorful Aurora over New Zealand
16/10/2024
Sometimes the night sky is full of surprises. Take the sky over Lindis Pass, South Island, New Zealand one-night last week. Instead of a typically calm night sky filled with constant stars, a busy and dynamic night sky appeared. Suddenly visible were pervasive red aurora, green picket-fence aurora, a red SAR arc, a STEVE, a meteor, and the Moon. These outshone the center of our Milky Way Galaxy and both of its two satellite galaxies: the LMC and SMC. All of these were captured together on 28 exposures in five minutes, from which this panorama was composed. Auroras lit up many skies last week, as a Coronal Mass Ejection from the Sun unleashed a burst of particles toward our Earth that created colorful skies over latitudes usually too far from the Earth's poles to see them. More generally, night skies this month have other surprises, showing not only auroras -- but comets. Jigsaw Challenge: Astronomy Puzzle of the Day
Copyright: Tristian McDonald
Comet Tsuchinshan-ATLAS Over the Lincoln Memorial
14/10/2024
Go outside at sunset tonight and see a comet! C/2023 A3 (Tsuchinshan–ATLAS) has become visible in the early evening sky in northern locations to the unaided eye. To see the comet, look west through a sky with a low horizon. If the sky is clear and dark enough, you will not even need binoculars -- the faint tail of the comet should be visible just above the horizon for about an hour. Pictured, Comet Tsuchinshan-ATLAS was captured two nights ago over the Lincoln Memorial monument in Washington, DC, USA. With each passing day at sunset, the comet and its changing tail should be higher and higher in the sky, although exactly how bright and how long its tails will be can only be guessed. Growing Gallery: Comet Tsuchinsan-ATLAS in 2024
Copyright: Brennan Gilmore
Northern Lights, West Virginia
12/10/2024
A gravel country lane gently winds through this colorful rural night skyscape. Captured from Monroe County in southern West Virginia on the evening of October 10, the starry sky above is a familiar sight. Shimmering curtains of aurora borealis or northern lights definitely do not make regular appearances here, though. Surprisingly vivid auroral displays were present on that night at very low latitudes around the globe, far from their usual northern and southern high latitude realms. The extensive auroral activity was evidence of a severe geomagnetic storm triggered by the impact of a coronal mass ejection (CME), an immense magnetized cloud of energetic plasma. The CME was launched toward Earth from the active Sun following a powerful X-class solar flare. Growing Gallery: Global aurora during October 10/11, 2024
Copyright: Jonathan Eggleston
Ring of Fire over Easter Island
11/10/2024
The second solar eclipse of 2024 began in the Pacific. On October 2nd the Moon's shadow swept from west to east, with an annular eclipse visible along a narrow antumbral shadow path tracking mostly over ocean, making its only major landfall near the southern tip of South America, and then ending in the southern Atlantic. The dramatic total annular eclipse phase is known to some as a ring of fire. Also tracking across islands in the southern Pacific, the Moon's antumbral shadow grazed Easter Island allowing denizens to follow all phases of the annular eclipse. Framed by palm tree leaves this clear island view is a stack of two images, one taken with and one taken without a solar filter near the moment of the maximum annular phase. The New Moon's silhouette appears just off center, though still engulfed by the bright disk of the active Sun.
Copyright: Yuri Beletsky
Five Bright Comets from SOHO
10/10/2024
Five bright comets are compared in these panels, recorded by a coronograph on board the long-lived, sun-staring SOHO spacecraft. Arranged chronologically all are recognizable by their tails streaming away from the Sun at the center of each field of view, where a direct view of the overwhelmingly bright Sun is blocked by the coronagraph's occulting disk. Each comet was memorable for earthbound skygazers, starting at top left with Comet McNaught, the 21st century's brightest comet (so far). C/2023 A3 Tsuchinshan-Atlas, approaching its perihelion with the active Sun at bottom center, has most recently grabbed the attention of comet watchers around the globe. By the end of October 2024, the blank 6th panel may be filled with bright sungrazer comet C/2024 S1 Atlas. ... or not.
Copyright: NASA
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.