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Ursa Astronomical Association
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Ursa Astronomical Association

Half-sky auroras - 16.3.2023 at 00.15 - 16.3.2023 at 01.40 Juva Observation number 113492

Visibility IV / V

Petri Martikainen, Ursa (Itä-Suomi)

Last night's northern lights in stereo. The idea is to look at a different image with each eye until the images slide on top of each other to form a three-dimensional image. A few stars are highlighted in each image to make it easier to "match" the images.

All winter, there have been plans to carry out this experiment, and it worked out surprisingly well for the first time. The northern lights also offered their best. The photo pairs were taken in the west direction with a focal length of 18 mm, the cameras were 5 km apart. The pictures of the pair of pictures were taken with 8-second exposures, the timing of the pictures has a throw of max. 1-3 seconds. Both cameras had identical wide-angle lenses purchased separately. If the images appear in the watch in the wrong size, adjustments will be made as necessary.

The pictures are in chronological order between 00:57 and 01:23. Picture 7 shows a larger version of the second picture.

More similar observations
Additional information
  • Aurora brightness
    • Bright auroras
  • Observed aurora forms
    • Arc info

      ARC The arcs are wider than the bands and do not fold as strongly. The arcs are normally neither very bright nor active.

      The arc is probably the most common form of aurora. When aurora show is a calm arc in the low northern sky it often doesn’t evolve to anything more during night. In more active shows the arc is often the first form to appear and the last to disappear.

      The lower edge of the arc is usually sharp but the upper edge can gradually blend into the background sky. As activity increases rays and folds normally develop, and the arcs turn gradually into bands.

      An aurora arc runs across the picture. Vertical shapes are rays. Photo by Atacan Ergin.

      Aurora Arc. Photo by Mauri Korpi.

      Aurora Arc. Photo by Anna-Liisa Sarajärvi.

      Aurora Arc. Photo by Matti Asumalahti.

    • Corona info

      CoronaA corona is a hand fan shaped structure, it usually forms south of the observer's zenith, most commonly consisting of rays or bands. The corona is usually the most beautiful part of the aurora show. It is bright and active, but on the other hand also short-lived.

      Aurora corona. Photo by Anna-Liisa Sarajärvi.

      Aurora corona. Photo by Merja Ruotsalainen.

      Corona formed from bands. Photo by Markku Ruonala.

      Aurora corona. Photo by Tapio Koski.

    • Band info

      Bands are usually narrower, more twisty at the bottom, brighter, and more active than arches. Bands usually develop from arches.

      Bands can form J and U shapes, sometimes even full spirals. The corona can also arise from bands. Bands are a fairly common form of aurora.

      Aurora band. Photo by Merja Ruotsalainen.

      Aurora band. Photo by Matias Takala.

      Aurora band. Photo by Lea Rahtu-Korpela.

      Aurora bands. Photo by Lauri Koivuluoma.

      Aurora band. Photo by Matias Takala.

    • Rays info

      The raysare parallel to the lines of force of the magnetic field, i.e. quite vertical, usually less than one degree thick light streaks. The rays can occur alone or in connection with other shapes, mainly with arcs and bands. Short rays are usually brightest at the bottom but dim quickly. The longest rays, even extending almost from the horizon to the zenith, are usually uniformly bright and quite calm, and unlike the shorter rays, most often occur in groups of a few rays or alone. Rays, like bands, are a very typical form of aurora.

      Artificial light pillars, which are a halo phenomenon visible in ice mist, can sometimes be very similar to the rays of aurora. Confusion is possible especially when the lamps that cause the artificial light pillars are far away and not visible behind buildings or the forest. The nature of the phenomenon is clear at least from the photographs.

      Rays. Picture of Tom Eklund.

      Rays. Photo by Mika Puurula.

      Two beams rise from the aurora veil. Photo by Anssi Mäntylä.

      Two radial bands. Show Jani Lauanne.

      Radial band and veil. Photo by Jussi Alanenpää.

      Two rays. Photo by Aki Taavitsainen.

      It may be possible to confuse such rays with artificial light columns. Compare the image below. Picture of Tom Eklund.

      There is no aurora in this image, but all the light poles - including the wide and diffuse bar seen at the top left - are artificial light pillars born of ice mist. Photo by Sami Jumppanen.

      Aurora and artificial light pillars. All the radial shapes in the picture above are probably artificial light pillars that coincide appropriately with the aurora band. In the image below, the aurora band has shifted and does not overlap with the pillars produced by the orange bulbs. There is no orange in auroras. Photo by Katariina Roiha

    • Pulsating patches info

      Pulsating patches or -aurora typically have more or less regular shape and size. They typically appear in the later part of an aurora display. They are almost always pulsating in variable periods.

  • Colors with unaided eye and other features
    • Green auroras info

      Green, seen with the naked eye, is one the most common colors of the aurora. The green color is derived from atomic oxygen.

      Green auroras. Lea Rahtu-Korpela.

      Green auroras. Photo by Juha Ojanperä.

    • Red coloration of the shapes lower edge info

      Red lower edge visible with the naked eye. The bands which are starting to level up their activity and are green colored have quite often a narrow red lower edge. This is the most common form of red color which is derived from molecular nitrogen.

      Aurora band with purple lower edge. Photo by Ilmo Kemppainen.

      The low hanging brightest aurora band is colored red at the lower edge. Photo by Tero Ohranen.

      Narrow purple reddish tones at the lower part of this aurora band. Photo by Merja Ruotsalainen.

      Purple band at the bottom. Photo by Panu Lahtinen.

    • Red coloration of the shapes top info

      Auroras which have red top part that can be seen with naked eye are most often observed in the bands and long rays. In this case the lower parts are usually green. If the upper parts are in sunlight, red may be stronger than green. This shade of red is due to the discharge of the excitation state of the atomic oxygen.

      Aurora that shift to reddish towards the top. Photo by Karri Pasanen. 

      Red top in a aurora band. Photo by Simo Aikioniemi.

      Red at the top of the aurora. Picture of Tom Eklund.

    • Pulsating auroras info

      Pulsating aurora. The brightness of the pulsating aurora usually varies rhythmically over a period that can be only a fraction of a second at its fastest, but can also be several minutes. Pulsing usually only occurs in(strong auroral conditions) higher quality shows , especially towards the end of them. However, the pulsation may be followed by yet another eruption. Sometimes the variation in brightness is at the same stage in the whole form, whereby the whole form "turns on and off" at the same time. Pulsation is also found in arches and bands, but above all in spots..

Technical information

Cameras Nikon D7000 and D7100, lenses Nikkor 18-55 mm.

Comments: 4 pcs
Tapio Lahtinen - 16.3.2023 at 23.11 Report this

Mielenkiintoinen kokeilu. Olispa ollut isompia kuvia...
Ja hassua kun tähdet näyttää olevan revontulien edessä.

Aki Karjalainen - 17.3.2023 at 00.17 Report this

Hienoja stereopareja! Minulle on aina ollut helppoa stereokuvien katselu sekä ristiinkatsomalla että katsetta hajauttamalla. Käsittääkseni näiden parien kuvat ovat siinä järjestyksessä, että ne on tarkoitettu katseltavaksi hajauttamistekniikalla, jolloin tähdet näkyvät revontulien takana niin kuin pitääkin. Silmät ristissä katsomalla stereovaikutelma kääntyy väärinpäin ja tähdet näyttävät olevan reposten edessä.

Jani Päiväniemi - 18.3.2023 at 12.50 Report this

Hienot kuvat! Kuvapari 6, jännä yön "silmä" katselee takaisin.

Petri Martikainen - 20.3.2023 at 13.54 Report this

Kiitos kommenteista! Kuvaparin kuvat ovat tuossa samassa järjestyksessä kuin livenäkin ja ainakin itselleni ne näkyvät oikein päin. En edes osaa katsoa niitä "ristiin". Koska kuvien täytyy olla lähekkäin, kovin isoja kuvia ei pysty katsomaan. Mutta seuraavalla kerralla otan pystykuvia niin kuviin tulee lisää korkeutta. Nälkä myös kasvoi syödessä ja haaveilen jo laajemmasta kuva-alasta, eli toisesta 8-millisestä objektiivista. Minusta tämä on kiehtovaa hommaa, vaikka kuvaparien käsittely olikin melko työlästä.

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