Contact information

Skywarden,
Ursa Astronomical Association
Kopernikuksentie 1
00130 Helsinki
taivaanvahti(at)ursa.fi

Ursa Astronomical Association

Active aurora band - 18.8.2017 at 01.15 - 18.8.2017 at 01.45 Yli-Ii Observation number 66336

Visibility III / V


The opening of the Northern Lights season was about the same time as in previous years. The intensity was very different. The corona opening in the sun brought very bright northern lights even though we had to wait quite a long time at night. About a quarter over one began to perceive a very faint arch but suddenly it became clear. As the arch rose the northern lights radiated in the arc and the lights danced in the sky quickly. The play lasted just over 20 minutes and after that the sky was empty again.



More similar observations
Additional information
  • Aurora brightness
    • Bright auroras
  • 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

    • 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.

    • 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.

Comments: 4 pcs
Tero Sipinen - 20.8.2017 at 23.16 Report this

Tavattoman hieno tuo ykköskuva!

Raija Ollikainen - 21.8.2017 at 10.36 Report this

Oje... ihanat kuvat! Sinä löydät aina kuviisi ainakin jonkin pienen lammikon täältä Oulun seudulta, joka ei totisesti ole mitään järvialuetta. Ja sitten onnistut kuvaamaan yön ainoan komean revontulihetken - kiitos lisää, weiter so! :)

Olli Sälevä - 21.8.2017 at 16.42 Report this

Ykköskuva on hieno.

Erkki Antikainen - 22.8.2017 at 13.26 Report this

Kylla kannatti odotella! Hienot kuvat! Varsinkin ensimmäinen.

Send a comment

Comments are checked and moderated before publication If you want to contact the observer directly about possibilities to use these images, use the Media -form.

*

*

*
characters left

By sending in this comment I confirm, that I've read and understood the the observation system's privacy policy.