View allAll Photos Tagged 558nm
Why the sky looks so colorful? An extraordinary multicolor light filled the sky during the capture of this image in March 2022 in the Antofagasta region in Chile.
The night sky is not 100% dark even in places like the Atacama Desert where is almost zero light pollution, the effect of the ultraviolet rays on the nitrogen and oxygen molecules during the day is responsible for bringing light to the sky at night, this reaction is known as chemiluminescence where take place the atoms and molecules' excitement 80 km or higher in the thermosphere.
In the airglow spectrum, the brightest and most common emission is green 558nm light from the atomic oxygen radiation but in some cases, we can capture red light from OH radicals at 86-87km and yellow light from sodium atoms altogether.
Place: Magic Bus, San Pedro de Atacama
Location: Antofagasta Region, Chile.
Date 03/31/2022 between 19:38 and 19:51 UTC-4
Elevation: 2450 m / 8038 ft
Technique: Panorama 40 singles images (no tracking or stacking)
Exif data
ISO: 1600, F1.4, 10 sec
Camera: Sony A7III Full Spectrum using Visible + H-Alpha filter
Lens: Sony FE 24mm f1.4 GM
Et voici la voie lactée au dessus d'un des plus beaux villages de France : Belvès
Cela fait des années que j'attendais que cette photo soit enfin possible... 😋
Depuis que la municipalité à choisie d'éteindre une partie des lumières du village, j'avais repéré ce point de vue qui permettait de mettre en valeur la cité médiévale sous un beau ciel étoilé ✨
Lors de cette sortie, j'étais accompagné de mon amis Alex Popov qui affectionne aussi les photos nocturnes.
Il n'y a que les nuages que l'on avait pas invité... Ils se sont incrustés au dernier moment en milieu de nuit mais tout compte fait, cela apporte une ambiance un peu chaude à l'image panoramique.
Cette couleur orange dans les nuages est due aux éclairages des lampadaires non éteints situés de l'autre côté du village ainsi que ceux des villes/villages environnants.
On peut aussi remarquer sur l'image un phénomène naturel qui se produit parfois dans notre ciel mais qui n'est visible que par des bonnes conditions de transparence : l'AIRGLOW
En français, cette "lumière du ciel nocturne" ou "lueur de l'air" est à l'origine d'un phénomène complexe où le rayonnement ultraviolet du soleil casse certaines molécules présentes dans notre atmosphère pendant la journée. Cela peut parfois entrainer plus tard dans la nuit des réactions chimiques qui produisent de la lumière (chimiluminescence)
Le plus couramment, la lumière produite est de couleur verte (rayonnement à la longueur d'onde 558nm)
Sur l'image, on remarque par endroit cette couleur verte caractéristique qui apporte toujours une certaine originalité aux images.
On remarque aussi que le clocher de la place de la Halle est tout vert. Il est assorti aux couleurs du ciel.
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Image panoramique réalisée par assemblage de 70 photos en pose unique de 8 secondes. Pas de suivi ni d’empilage.
Prise de vue dans la nuit du 20 avril 2023 vers 3h30 du matin
The second day of this month I went to Mount Emei alone. Stayed only one night to cure for the itch that watching stars on this mountain.
The new moon set early, then I saw two tiny dots of light. One was the Wanfo Temple on the opposite peak, another is the canopus, usually invisible due to extinction by low atmosphere. Below them was a sea of clouds, interspersed city lights from Leshan and Chengdu.
The background sky is covered with airglow. The formation of airglow is not so simplex, both chemical and physical processes can be the reason.
A dominated process is the de-excitation of atomic oxygen. Solar radiation brings high energy photons to our atmosphere, they excite atomic oxygen from ground state to upper ones. When an excited atom jumps back to lower energy state, photon with characterized wavelength is emitted.
But why the airglow only appears in high altitude? Collisions between the excited atom and other particles in the air play a major role in the answer.
As quantum mechanics claims, all the transitions between states are matters of probability. Some of them are easy to happen while others are not, the reason of this difference is involved with the selection rule, which is a result of classic quantum mechanics.
If the probability of a transition is extremely small, we say it is forbidden. And It is exactly the case for jumpings corresponding to red(630nm) and green(558nm) emission lines of atomic oxygen (i.e. the excited atom won't decay immediately after jumping to high level). However, the excited atom neither will obediently stay in the upper energy level; instead, it will collide with other particles and lose energy, actually most of the excited atoms decay in this way.
But things are different in upper air, there are not so many particles around, leading to less collisions, leaving enough time to wait for the happening of the small probability events (the forbidden transitions). In this way, the green and red photons escape. More specifically, the OI forbbiden line.
If you observe the red spectrum line with a spectrophotometer, you will find that the red line is actually doublet (630nm and 636.4nm), it is caused by the interaction of orbit and spin angular momentum of the particle.
Something a little different: The Milky Way over Earth's limb, captured from over 400 kilometers above the Pacific Ocean by astronaut Kjell Lindgren. Processed for natural color by me.
This is a natural color image, meaning that star colors correspond to their spectral type and narrowband emissions match their wavelength. Alongside the Milky Way in this image is the presence of 3 different types of airglow:
Near the Earth's limb at around 90km up are airglow caused by 558nm atomic oxygen emissions (Chartreuse green) and 589.3nm sodium emissions *Yellow).
Higher up at around 150 to 350km the glow is caused by emissions from atomic oxygen at 630nm (Red) and also Hydroxl (OH) emissions.
Aquisition Info:
ISS044-E-45215
eol.jsc.nasa.gov/SearchPhotos/photo.pl?mission=ISS044&...
ISO-12800
1x1.3"
f/1.4
Gear Used:
Nikon D4
Nikkor 28mm f/1.4
Software:
Adobe DNG Converter
Adobe Camera Raw
PixInsight 1.8
Adobe Photoshop CS5.1
Credit: NASA/Kjell Lindgren/Hypatia Alexandria
30 sec exposure, Canon 550D, f2.8, 1600ISO
Note laser beam effect! Shutter opened half way through passage of meteor. Green trail on left is 558nm emission from ionised Oxygen. Here you see it without the incandescent meteor trail so it's incredibly clear.
"Airglow Australis"
You are never too old to set another goal or to dream a new dream. — CS Lewis, (novelist)
The airglow is the light of electronically and/or vibration-rotationally excited atoms and molecules 80 km or higher.
The brightest emission is green 558nm light from oxygen atoms in a layer 90-100 km high. The emission layer is clearly visible from earth orbit.
Image source:Paul Wilson Images NZ