Η Αστρονομική Εικόνα της Ημέρας από τη NASA
W5: The Soul Nebula
17/12/2025
Stars are forming in the Soul of the Queen of Aethopia. More specifically, a large star forming region called the Soul Nebula can be found in the direction of the constellation Cassiopeia, whom Greek mythology credits as the vain wife of a King who long ago ruled lands surrounding the upper Nile river. Also known as Westerhout 5 (W5), the Soul Nebula houses several open clusters of stars, ridges and pillars darkened by cosmic dust, and huge evacuated bubbles formed by the winds of young massive stars. Located about 6,500 light years away, the Soul Nebula spans about 100 light years and is usually imaged next to its celestial neighbor the Heart Nebula (IC 1805). The featured image, taken from near Nashville, Tennessee, USA, is a composite of 234 hours of exposures made in different colors: red as emitted by hydrogen gas, yellow as emitted by sulfur, and blue as emitted by oxygen. Explore the Universe: Random APOD Generator
Copyright: Jeffrey Horne
Προηγούμενες Αστρονομικές Εικόνες της Ημέρας από τη NASA
Messier 109
27/06/2025
Big beautiful barred spiral galaxy Messier 109 is the 109th entry in Charles Messier's famous catalog of bright Nebulae and Star Clusters. You can find it just below the Big Dipper's bowl in the northern constellation Ursa Major. In fact, bright dipper star Phecda, Gamma Ursa Majoris, produces the glare at the upper right corner of this telescopic frame. M109's prominent central bar gives the galaxy the appearance of the Greek letter "theta", θ, a common mathematical symbol representing an angle. M109 spans a very small angle in planet Earth's sky though, about 7 arcminutes or 0.12 degrees. But that small angle corresponds to an enormous 120,000 light-year diameter at the galaxy's estimated 60 million light-year distance. The brightest member of the now recognized Ursa Major galaxy cluster, M109 (aka NGC 3992) is joined by spiky foreground stars. Three small, fuzzy bluish galaxies also on the scene, identified (top to bottom) as UGC 6969, UGC 6940 and UGC 6923, are possibly satellite galaxies of the larger barred spiral galaxy Messier 109.
Copyright: Robert Eder
The Seagull Nebula
26/06/2025
An interstellar expanse of glowing gas and obscuring dust presents a bird-like visage to astronomers from planet Earth, suggesting its popular moniker, the Seagull Nebula. This broadband portrait of the cosmic bird covers a 3.5-degree wide swath across the plane of the Milky Way, in the direction of Sirius, alpha star of the constellation of the Big Dog (Canis Major). The bright head of the Seagull Nebula is cataloged as IC 2177, a compact, dusty emission and reflection nebula with embedded massive star HD 53367. The larger emission region, encompassing objects with other catalog designations, is Likely part of an extensive shell structure swept up by successive supernova explosions. The notable bluish arc below and right of center is a bow shock from runaway star FN Canis Majoris. Dominated by the reddish glow of atomic hydrogen, this complex of interstellar gas and dust clouds with other stars of the Canis Majoris OB1 association spans over 200 light-years at the Seagull Nebula's estimated 3,800 light-year distance.
Copyright: Timothy Martin
Rubin's First Look: A Sagittarius Skyscape
25/06/2025
This interstellar skyscape spans over 4 degrees across crowded starfields toward the constellation Sagittarius and the central Milky Way. A First Look image captured at the new NSF–DOE Vera C. Rubin Observatory, the bright nebulae and star clusters featured include famous stops on telescopic tours of the cosmos: Messier 8 and Messier 20. An expansive star-forming region over a hundred light-years across, Messier 8 is also known as the Lagoon Nebula. About 4,000 light-years away the Lagoon Nebula harbors a remarkable cluster of young, massive stars. Their intense radiation and stellar winds energize and agitate this cosmic lagoon's turbulent depths. Messier 20's popular moniker is the Trifid. Divided into three parts by dark interstellar dust lanes, the Trifid Nebula's glowing hydrogen gas creates its dominant red color. But contrasting blue hues in the colorful Trifid are due to dust reflected starlight. The Rubin Observatory visited the Trifid-Lagoon field to acquire all the image data during parts of four nights (May 1-4). At full resolution, Rubin's magnificent Sagittarius skyscape is 84,000 pixels wide and 51,500 pixels tall.
Copyright: NASA
In the Center of Spiral Galaxy M61
24/06/2025
Is there a spiral galaxy in the center of this spiral galaxy? Sort of. Image data from the Hubble Space Telescope, the European Southern Observatory, and smaller telescopes on planet Earth are combined in this detailed portrait of face-on spiral galaxy Messier 61 (M61) and its bright center. A mere 55 million light-years away in the Virgo Cluster of Galaxies, M61 is also known as NGC 4303. It's considered to be an example of a barred spiral galaxy similar to our own Milky Way. Like other spiral galaxies, M61 also features sweeping spiral arms, cosmic dust lanes, pinkish star forming regions, and young blue star clusters. Its core houses an active supermassive black hole surrounded by a bright nuclear spiral -- infalling star-forming gas that itself looks like a separate spiral galaxy. APOD Turns 30!: Free public lecture in Cork, Ireland TONIGHT (Tuesday) at 7 pm
Copyright: NASA
W5: Pillars of Star Formation
23/06/2025
How do stars form? Images of the star forming region W5 like those in the infrared by NASA's Wide Field Infrared Survey Explorer (WISE, later NEOWISE) satellite provide clear clues with indications that massive stars near the center of empty cavities are older than stars near the edges. A likely reason for this is that the older stars in the center are actually triggering the formation of the younger edge stars. The triggered star formation occurs when hot outflowing gas compresses cooler gas into knots dense enough to gravitationally contract into stars. In the featured scientifically colored infrared image, spectacular pillars left slowly evaporating from the hot outflowing gas provide further visual clues. W5 is also known as Westerhout 5 (W5) and IC 1848. Together with IC 1805, the nebulas form a complex region of star formation popularly dubbed the Heart and Soul Nebulas. The featured image highlights a part of W5 spanning about 2,000 light years that is rich in star forming pillars. W5 lies about 6,500 light years away toward the constellation of Cassiopeia. APOD Turns 30!: Free public lecture in Cork, Ireland tomorrow (Tuesday) at 7 pm
Copyright: : Francesco Antonucci
A Berry Bowl of Martian Spherules
22/06/2025
How were these unusual Martian spherules created? Thousands of unusual gray spherules made of iron and rock and dubbed blueberries were found embedded in and surrounding rocks near the landing site of the robot Opportunity rover on Mars in 2004. To help investigate their origin, Opportunity found a surface dubbed the Berry Bowl with an indentation that was rich in the Martian orbs. The Berry Bowl is pictured here, imaged during rover's 48th Martian day. The average size of a Martian blueberry rock is only about 4 millimeters across. By analyzing a circular patch in the rock surface to the left of the densest patch of spherules, Opportunity obtained data showing that the underlying rock has a much different composition than the hematite rich blueberries. This information contributes to the growing consensus that these small, strange, gray orbs were slowly deposited from a bath of dirty water. APOD Turns 30!: Free Public Lecture in Cork, Ireland on Tuesday, June 24 at 7 pm
Copyright: NASA
Two Worlds, Two Analemmas
21/06/2025
Sure, that figure-8 shaped curve you get when you mark the position of the Sun in Earth's sky at the same time each day over one year is called an analemma. On the left, Earth's figure-8 analemma was traced by combining wide-angle digital images recorded during the year from December 2011 through December 2012. But the shape of an analemma depends on the eccentricity of a planet's orbit and the tilt of its axis of rotation, so analemma curves can look different for different worlds. Take Mars for example. The Red Planet's axial tilt is similar to Earth's, but its orbit around the same sun is more eccentric (less circular) than Earth's orbit. As seen from the Martian surface, the analemma traced in the right hand panel is shaped more like a tear drop. The Mars rover Opportunity captured the images used over the Martian year corresponding to Earth dates July 2006 to June 2008. Of course, each world's solstice dates still lie at the top and bottom of their different analemma curves. The last Mars northern summer solstice was May 29, 2025. Our fair planet's 2025 northern summer solstice is at June 21, 2:42 UTC.
Copyright: Tunc Tezel
Major Lunar Standstill 2024-2025
20/06/2025
dmonton, Alberta, Canada, planet Earth lies on the horizon. in this stack of panoramic composite images. In a monthly time series arranged vertically top to bottom the ambitious photographic project follows the annual north-south swing of sunrise points, from June solstice to December solstice and back again. It also follows the corresponding, but definitely harder to track, Full Moon rise. Of course, the north-south swing of moonrise runs opposite sunrise along the horizon. But these rising Full Moons also span a wider range on the horizon than the sunrises. That's because the well-planned project (as shown in this video) covers the period June 2024 to June 2025, centered on a major lunar standstill. Major lunar standstills represent extremes in the north-south range of moonrise driven by the 18.6 year precession period of the lunar orbit.
Copyright: Luca Vanzella
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.