All-sky aurora - 17.3.2015 at 19.35 - 18.3.2015 at 01.26 Espoo Observation number 34667

• Aurora brightness
• • Bright auroras
• Colors with unaided eye and other features
• • Streaming auroras

    Streaming. In streaming aurora fast irregular variations in brightness occur along the horizontal dimension of homogeneous shapes.

  • Flickering auroras

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

  • Flaming auroras

    Flaming. This rare subclass of aurora does not mean so much a single shape, but a large area in the sky. In the flaming aurora, bright waves that are sweeping upward towards the magnetic zenith emerge in the sky. Very rarely waves can wipe downwards. Bands are usually reported during flaming, less often spots.

  • Pulsating auroras

    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..

  • Blue auroras

    Clearly blue auroras can be seen only during the best aurora displays close to the maximum phase or soon after it. Sometimes blue auroras can be seen shortly after the sunset at the top part of the auroral shapes, specially rays. It is created by the mission of the ionized nitrogen molecules created by the suns radiation.

    Strongly colored blue auroras. Photo by Jorma Mäntylä.

    Blue top parts of the aurora. Image by Tom Eklund. 

    Blue top parts of the aurora. Image by Jaakko Hatanpää.

    Partly blue corona. Photo by Tapio Koski.

    Faintly blue top parts of an aurora veil. Photo by Jaakko Hatanpää.

  • Fully red auroras

    Completely dark red aurora is a very rare and strikingly handsome revelation. This phenomenon is also due to the discharge of an excitation state of an atomic oxygen.

    Throughout red aurora. Photo by Tobias Billings.

  • Red coloration of the shapes top

    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.

  • Red coloration of the shapes lower edge

    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.

  • Green auroras

    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

    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.

• Observed aurora forms
• • ;Form not identifiable;Veil;Rays;Band;Corona;Arc

Canon 7D, Sigma 4.5 mm f / 2.8, 3 and 6 s, ISO 800, 3656 images

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