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Ursa Astronomical Association

Half-sky auroras - 27.9.2019 at 22.15 - 27.9.2019 at 23.00 Eurajoki, Luvia Observation number 85939

Visibility IV / V

Mikko Grönroos, Ursa (Länsi-Suomi)

A refreshing and wonderful northern lights show here in Southern Finland for a long time! I didn’t know I was filming the STEVE arc until afterwards. It was very much separated from the usual northern lights. The air direction was also different: I calculated that near the horizon the direction would be about 290 degrees, that is, almost to the west. I saw the formation of STEVE from the beginning. The first rays appeared at about 22:15 and at its widest the belt extended to zenith at about 22:30. The rays of the belt moved in a wave from the zenith towards the horizon. Shortly thereafter, the belt began to retreat toward the horizon. Apparently from a perspective, STEVE seemed to brighten as he was farther away, allowing me to compose it into tree branches. I also got the green rays of the picket fence in my pictures. I stopped shooting at about 11pm when the surrounding mist began to condense on the front lens of the lens. At the time, STEVE was still visible, but dimmed somewhat.

More pictures and videos composed of them, as well as stuff about the shooting situation can be found in my Instagram account @kuviavalo.

More similar observations
Additional information
  • Aurora brightness
    • Bright auroras
  • Colors with unaided eye and other features
    • Flickering auroras info

      Flickering. This rare subclass refers to a situation where irregular variations in brightness occur in aurora, such as in fluttering flames.

    • 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.

    • 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.

    • White auroras info

      Paljain silmin valkoinen väri näkyy useimmiten himmeissä näytelmissä, kun silmä ei kykene erottamaan mitään varsinaista väriä. Harvoin kirkkaissa näytelmissä valkoinen väri voi myös syntyä sopivista vihreän, punaisen ja sinisen yhdistelmistä.

    • Violet auroras info

      Usually in Lapland or even in the south you can see purple auroras in stronger aurora shows. The most common color in auroras along with green and red.

  • Observed aurora forms
    • STEVE-arc info

      STEVE (Strong Thermal Emission Velocity Enhancement), Pink, radial aurora-like arc  . The STEVE arc is seen clearly separated from the main aurora arc of the northern sky. It forms a long and narrow west-east aligned, usually dim form. It does not belong to traditional auroras as a phenomenon, but may appear same time with them. Occasionally there may also be a green, "toothed" band called ”picket fence” at the bottom of Steve.  

      Riku Talvio, STEVE
      Photo by: Riku Talvio

    • Veil info

      Veil is the most bland and very common form of aurora. It usually covers its homogeneous dim glow over a wide area of the sky at once. Most often, the veil is seen in the calmer and quiet phase of the night after the aurora maximum as a background for other forms. The veil can also occur alone and in that case it will be quite difficult to reliably identify as an aurora, especially at a observation site which has a lot of light pollution.

      A similar glow of light can also be caused by airborne moisture, smoke, or a very thin layer of clouds that reflects the light that hits them. However, clouds can also be used to identify veil, especially if the middle or upper cloud appears dark against a lighter background, then it is very likely to be aurora veil if the brightness of the background sky is not due to the rising or falling Moon or Sun. When photographing, very long exposure times usually reveal the green colour of the veil auroras.

      Veil and rays. Photo by Esa Palmi.

      Red aurora veil. Photo by Marko Mikkilä.


      Veil. Photo by Milla Myllymaa.


      Aurora veil that changes color from green at the lower edge through purple to blue at the top. Photo by Jaakko Hatanpää.


      Dim green veil. Photo by Jarmo Leskinen.


      Radial aurora band surrounded by veil. Photo by Jussi Alanenpää.

    • 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

    • 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.

Comments: 5 pcs
Tero Sipinen - 4.10.2019 at 20.14 Report this

Todella hieno dokumentti tästä ilmiöstä! Eikä toki vain dokumenttina hieno, vaan upeat kuvat muutenkin. Olinkin jo ihmetellyt, että eikö kukaan saanut timelapsea STEVE:stä, mutta nyt sekin puute on paikattu. Osin "synteettinen" timelapse, mutta liikkuvaa kuvaa kuitenkin! Hienoa, että sait todistaa alusta alkaen tätä ilmiötä. Itse en ennen tätä 27.9. Näytelmää tiennyt, että itse STEVE:kin voi olla noin raidallinen, kuten tuo vihreä "säleaita" :o

Mikko Grönroos - 4.10.2019 at 21.34 Report this

Kiitos Tero kannustavasta kommentista, lämmittää kovasti! Jos olisin silloin tiennyt kuvaavani STEVE:ä, olisin ottanut enemmän myös timelapse-kuvia. Itse asiassa en edes ajatellut timelapsea silloin. Satuin vaan ottamaan muutaman peräkkäisen kuvan, hyvä että edes ne. En oikein ole varma, voiko STEVE:n säteiden aaltoilevaa liikettä kuvata lepattavaksi, kuten olin merkannut. En oikein muutakaan osannut laittaa.

Mikko Grönroos - 4.10.2019 at 21.41 Report this

Kuvien kellonajat ja päivämäärät näyttävän olevan todella pielessä. Kuvat ovat kuitenkin aikajärjestyksessä lukuunottamatta ensimmäistä kuvaa.

Juha Kinnunen - 7.10.2019 at 12.19 Report this

Hieno havaintokertomus ja kuvat, kiitos!

Mikko Grönroos - 7.10.2019 at 20.40 Report this

Kiitos Juha!

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