ASTRONOMY - Solar Eclipse from a Ship

 2023 April 29

Solar Eclipse from a Ship
Image Credit: Fred Espenak

Explanation: Along a narrow path that mostly avoided landfall, the shadow of the New Moon raced across planet Earth's southern hemisphere on April 20 to create a rare annular-total or hybrid solar eclipse. From the Indian Ocean off the coast of western Australia, ship-borne eclipse chasers were able to witness 62 seconds of totality though while anchored near the centerline of the total eclipse track. This ship-borne image of the eclipse captures the active Sun's magnificent outer atmosphere or solar corona streaming into space. A composite of 11 exposures ranging from 1/2000 to 1/2 second, it records an extended range of brightness to follow details of the corona not quite visible to the eye during the total eclipse phase. Of course eclipses tend to come in pairs. On May 5, the next Full Moon will just miss the dark inner part of Earth's shadow in a penumbral lunar eclipse.

ASTRONONOMY - Runaway Star Alpha Camelopardalis

 2023 April 28

Runaway Star Alpha Camelopardalis
Image Credit: André Vilhena

Explanation: Like a ship plowing through cosmic seas, runaway star Alpha Camelopardalis has produced this graceful arcing bow wave or bow shock. The massive supergiant star moves at over 60 kilometers per second through space, compressing the interstellar material in its path. At the center of this nearly 6 degree wide view, Alpha Cam is about 25-30 times as massive as the Sun, 5 times hotter (30,000 kelvins), and over 500,000 times brighter. About 4,000 light-years away in the long-necked constellation Camelopardalis, the star also produces a strong stellar wind. Alpha Cam's bow shock stands off about 10 light-years from the star itself. What set this star in motion? Astronomers have long thought that Alpha Cam was flung out of a nearby cluster of young hot stars due to gravitational interactions with other cluster members or perhaps by the supernova explosion of a massive companion star.

ASTRONOMY -The Tarantula Nebula from SuperBIT

 2023 April 27

The Tarantula Nebula from SuperBIT
Image Credit: SuperBIT, NASA

Explanation: The Tarantula Nebula, also known as 30 Doradus, is more than a thousand light-years in diameter, a giant star forming region within nearby satellite galaxy the Large Magellanic Cloud. About 160 thousand light-years away, it's the largest, most violent star forming region known in the whole Local Group of galaxies. The cosmic arachnid is near the center of this spectacular image taken during the flight of SuperBIT (Super Pressure Balloon Imaging Telescope), NASA's balloon-borne 0.5 meter telescope now floating near the edge of space. Within the well-studied Tarantula (NGC 2070), intense radiation, stellar winds and supernova shocks from the central young cluster of massive stars, cataloged as R136, energize the nebular glow and shape the spidery filaments. Around the Tarantula are other star forming regions with young star clusters, filaments, and blown-out bubble-shaped clouds. SuperBIT's wide field of view spans over 2 degrees or 4 full moons in the southern constellation Dorado.

ART FRACTAL - Détail de l'ensemble de Mandelbrot

Cette fractale représente un détail de l'ensemble de Mandelbrot. Deux figures en forme de S quasi identiques, l'une dans les tons bleu-jaune et l'autre dans les nuances rose-bleu, semblent se tenir par la main. Comme pour toute fractale, si on regarde de près un détail, on obtient la même structure que l'ensemble. 

© Futura

AERONAUTIQUE - Avions de légende - Le Messerschmitt Bf 109, un avion de chasse de référence

Conçu dans les années 1930 par l'ingénieur allemand Willy Messerschmitt, le Bf 109 s'illustra d'abord durant la guerre d'Espagne. Sa sophistication favorisa la création de techniques de combat inédites qui lui assurèrent une domination des airs durant toute la première moitié de la seconde guerre mondiale. L'appareil, qui fut produit à 33.000 exemplaires, utilisa successivement des moteurs Junkers Jumo et Mercedes-Benz.

© Tony Cyphert, CC by-nc 2.0

ASTRONOMY - The Moon through the Arc de Triomphe

 2023 April 26

The Moon through the Arc de Triomphe
Image Credit & Copyright: Stefano Zanarello

Explanation: Was this a lucky shot? Although many amazing photographs are taken by someone who just happened to be in the right place at the right time, this image took skill and careful planning. First was the angular scale: if you shoot too close to the famous Arc de Triomphe in Paris, France, the full moon will appear too small.  Conversely, if you shoot from too far away, the moon will appear  too large and not fit inside the Arc. Second is timing: the Moon only appears centered inside the Arc for small periods of time -- from this distance less than a minute. Other planned features include lighting, relative brightness, height, capturing a good foreground, and digital processing. And yes, there is some luck involved -- for example, the sky must be clear. This time, the planning was successful, bringing two of humanity's most famous icons photographically together for all to enjoy.

ASTRONOMY - Northern Lights over Southern Europe

 2023 April 25

Northern Lights over Southern Europe
Image Credit & Copyright: Lorenzo Cordero

Explanation: Did you see an aurora over the past two nights? Many people who don't live in Earth's far north did. Reports of aurora came in not only from northern locales in the USA as Alaska, but as far south as Texas and Arizona. A huge auroral oval extended over Europe and Asia, too. Pictured, an impressively red aurora was captured last night near the town of Cáceres in central Spain. Auroras were also reported in parts of southern Spain. The auroras resulted from a strong Coronal Mass Event (CME) that occurred on the Sun a few days ago. Particles from the CME crossed the inner Solar System before colliding with the Earth's magnetosphere. From there, electrons and protons spiraled down the Earth's northern magnetic field lines and collided with oxygen and nitrogen in Earth's atmosphere, causing picturesque auroral glows. Our unusually active Sun may provide future opportunities to see the northern lights in southern skies.

ASTRONOMY - NGC 1333: Stellar Nursery in Perseus

 2023 April 22

NGC 1333: Stellar Nursery in Perseus
Image Credit: Science - NASA, ESA, STScI, Processing - Varun Bajaj (STScI),
Joseph DePasquale (STScI), Jennifer Mack (STScI)

Explanation: In visible light NGC 1333 is seen as a reflection nebula, dominated by bluish hues characteristic of starlight reflected by interstellar dust. A mere 1,000 light-years distant toward the heroic constellation Perseus, it lies at the edge of a large, star-forming molecular cloud. This Hubble Space Telescope close-up frames a region just over 1 light-year wide at the estimated distance of NGC 1333. It shows details of the dusty region along with telltale hints of contrasty red emission from Herbig-Haro objects, jets and shocked glowing gas emanating from recently formed stars. In fact, NGC 1333 contains hundreds of stars less than a million years old, most still hidden from optical telescopes by the pervasive stardust. The chaotic environment may be similar to one in which our own Sun formed over 4.5 billion years ago. Hubble's stunning image of the stellar nursery was released to celebrate the 33rd anniversary of the space telescope's launch.

ASTRONOMY - A Waterspout in Florida

 2023 April 23

A Waterspout in Florida
Image Credit & Copyright: Joey Mole

Explanation: What's happening over the water? Pictured here is one of the better images yet recorded of a waterspout, a type of tornado that occurs over water. Waterspouts are spinning columns of rising moist air that typically form over warm water. Waterspouts can be as dangerous as tornadoes and can feature wind speeds over 200 kilometers per hour. Some waterspouts form away from thunderstorms and even during relatively fair weather. Waterspouts may be relatively transparent and initially visible only by an unusual pattern they create on the water. The featured image was taken in 2013 July near Tampa Bay, Florida. The Atlantic Ocean off the coast of Florida is arguably the most active area in the world for waterspouts, with hundreds forming each year.

AERONAUTIQUE - Avions de légende - Le Supermarine Spitfire et son moteur Rolls-Royce

Avec le Messerschmitt Bf 109, le Supermarine Spitfire est l'autre avion de chasse légendaire à s'être illustré durant la seconde guerre mondiale. C'est notamment grâce à lui que la Royal Air Force britannique a pu remporter la célèbre bataille d'Angleterre.

Ce monoplan à ailes elliptiques se caractérise par son profil très aérodynamique qui lui permettait d'atteindre les 650 km/h grâce à son moteur Rolls-Royce. Le Supermarine Spitfire fut produit à plus de 20.300 exemplaires, avec des déclinaisonsutilisées par plusieurs pays, notamment l'Égypte, la France, Israël ou encore la Turquie.

© Jez, CC by-nc 2.0

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