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Ursa Astronomical Association
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Ursa Astronomical Association

Quiet aurora arc - 13.11.2012 at 21.16 - 13.11.2012 at 21.37 Tampere Observation number 8946

Visibility II / V

Jari Luomanen, Ursa (Länsi-Suomi)

Now for a little while it was quite nice to see you, very dim only. Had to be very well lit. Red wasn’t visible to the naked eye, my eyes didn’t have time to get used to the dark when I played with the camera screens and flashlight all the time when there was enough clear sky. It could have been "guessed" to be there (and in that red torch on the east edge it was obvious), but it would have taken a little more time to see properly. It was unnecessarily hectic as the clouds rushed from the north on top.

More similar observations
Additional information
  • Aurora brightness
    • Dim auroras
  • Colors with unaided eye and other features
    • 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.

  • Observed aurora forms
    • 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

    • 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.

Comments: 3 pcs
Olli Sälevä - 14.11.2012 at 17.11 Report this

Punaista valoa taskulamppuun, niin säilyy näkökyky paremmin pimeässä. :-)

Jari Luomanen - 14.11.2012 at 17.14 Report this

Voisi olla kyllä. Otsalampussani on joku alle lumenin sen pienin asetus, mutta kameroiden näytöt tuppaavat olemaan kirkkaita ja alun tohinassa niiden kanssa tulee puljattua paljon. Tuossa kun varsinaista peliaikaa oli vain vartin verran. Suoraan kirkkaista valoista rantaan ja siitä sitten kamerat töihin. :)

Mikko Peussa - 14.11.2012 at 23.50 Report this

Onhan se aikamoista touhua häärätä pimeässä otsalamppu päässä ja kun vielä itse joudun siinä välissä laittamaan lukulasejakin silmille. Sitten vielä pilvet pukkaa päälle, niin kiirettä pitää. Mahtavia kuvia on nämäkin kaikesta huolimatta. Tämä purppura punerrus on hieno ja kun siitäkin on keskusteltu niin testailin ja katselin paljon vanhoja kuviani ihan 80-luvun dioista saakka. Pidemmällä valotuksella tosiaan purppura tulee paremmin esille, joten valotusajalla on myös merkitystä, vaikka toisinkin on väitetty. Alivalotuksen puolelle kun mennään niin punerrus häviää selvästi ennen vihreää. Tätä loistavaa ykköskuvaasi testailemalla sen myös huomaa hyvin. Joten kun reposissa esiintyy punerrusta niin pidempi valotusaika tuo sen selkeästi paremmin esille.

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