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Ursa Astronomical Association
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Ursa Astronomical Association

Half-sky auroras - 24.10.2017 at 19.53 - 24.10.2017 at 22.00 Laitila Observation number 67837

Visibility IV / V

I stumbled in peace from home to the home, happily unaware of what would happen in the sky in a moment.

I stopped for some reason at the Northern Lights shooting site, the idea was to follow the evening cloud situation.

When I got out of the car, my chin fell to my knees.

No clouds and three green belts ran across the sky over the car !! So what the hell?

Above the head is the pulse of a dilute lazy corona.

Anyone guess the next move?

Rally here for the day!

Focus instantly turned from a dreamy cart into a wrc rally racer. The driver woke up and the captain's normally-slow weight weighed without fogging.

When I got home, I grabbed the camera (which luckily was ready!) And in a hurry I glowed at my husband, “dazed, there’s pretty barren northern lights”… and out the door with those words.

Fast sky to the field. Corona had fluttered, but the belts and spots were full all over the south. To the north was a dim oval. The emphasis is really on the word matte. Instead, there were deer hustle and bustle in the south!

Camera to sing and admire the events next to it. A green arch sprays over your head, it's like Utsjoki at its best. The Milky Way was accompanied by a red arch. Unfortunately, I couldn’t influence the third companion, it was Comrade Cloud Ferry.

In addition to the green belts, the only thing the eye perceived was once again a single red arch climbing high. So I focused on describing the power to the south and above the head, nothing happened in the north. The clouds of evil but began to block the observation of the arc, the edge of the cloud board slowly but surely flew towards Laitila.

No rays were worse than counting those red stuff. Quite the norm for northern lights these were not. At the low was a clearly green arch, with a blank in between and then the red, dancing in the south, you come with green spots.

I would go home to warm up and throw another jog in the evening. The arch was and still is, but below and the red revos and the red arch had disappeared. It was an amazingly breathtaking evening. Directly from the opening to describe…

The last images I have processed correspond as closely as possible to yesterday’s colors and conditions. In image processing, I slammed the light pollution as low as I could. The red arc was sometimes visible to the eye as a light / reddish streak, which occasionally faded and sometimes strengthened again.

My regret that Mörkö was haunted by the pictures… now I didn't have time to compose: D

EDIT: Sar arch checked. #sarg

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.

    • 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.

    • Stable Auroral Red (SAR) arc info

      The Stable Auroral Red arcs (SAR arcs)  are usually clearly distanced to the south from the aurora oval and is a very opaque and normally red ribbon. In most cases SAR arcs are only visible in the photo or on the liveview screen of the SLR camera. Using a camera with very high sensitivity is the best method for capturing these faint arcs. The arch usually settles between east and west.

      A stable red arc of aurora is a rare phenomenon. In some rare occasions, several SAR arcs may be simultaneously visible.

      The first SAR arcs of the Skywarden were observed on nights between November 3-4. and 4-5. days in 2015 in the latitudes of central Finland.   

      SAR arc photographed by Lasse Nurminen 2018. Observation of the Skywarden 79113.

    • Red Arc with Green Diffuse Aurora (RAGDA) info

      Red Arc with Green Diffuse Aurora (RAGDA), is a two-component form of northern lights that occurs south of the oval.

      Both parts of the aurora are formed when positive particles from the magnetosphere hit the Earth's upper atmosphere. The phenomenon occurs before magnetic midnight during large aurora substorms and is best distinguished when it deteches southward from the bright rays of the substorm aurora.

      The phenomenon consists of a faint red arc, which looks a lot like a Stable Auroral Red (SAR)-arc. The common factor for these two red arcs is the reaction of the ring current with the substorm.

      Antero Ohranen, RAGDA
      A Red Arc with Green Diffuse Aurora
      Photo: Antero Ohranen


      Below the red arc are green diffuse patches or sausage-like shapes. RAGDA's green aurora is essentially featureless and without any rays. It may appear slightly more bluish in camera images compared to the green aurora of the oval.

      Lasse Nurminen, RAGDA
      RAGDA's green has slightly more bluish shade than the rest of the oval.
      Photo: Lasse Nurminen


      Sometimes the red arc and the green patches are clearly separated from the aurora oval and sometimes almost in contact with the southward edge of the oval.

      During an active substorm, the green northern lights can sometimes be seen with red tops. These usually have rays that RAGDA's green aurora lacks.

      An emissionless gap without any aurora light can be observed between the red arc and green diffuse aurora. The two features don't seem to be connected. Of the two aligned structures, the red one is located ~ 100 kilometers higher than the green aurora.

      Markku Ruonala, RAGDA
      There seems to be an empty area without any aurora light between the red and green aurora.
      Photo: Markku Ruonala


      The event is dynamic. It sometimes starts with green blobs, then a red arc appears. These two can also appear in the sky at the same time. The shapes move often from east to west. Then the Red Arc with Green Diffuse Aurora fades away and only the red arc remains visible in the sky. The red arc is recognized as the SAR arc.

      Observing this phenomenon is easier when the night sky is clear and dark before magnetic midnight. When looking for the red arc with green diffuse aurora, the best results can be achieved by pointing the camera towards south or southwest of the brightest part of the oval.

      A wide-angle lens is recommended for photographing the shape of the red arc going over the sky, but a regular lens can also be used. The red arc is quite dim, so the exposure times needed are typically longer than the ones for northern lights.

      Pirjo Koski, RAGDA
      Two RAGDA-arcs
      Photo: Pirjo Koski


      If the red arc cannot be distinguished in the images, the phenomenon identification 'Diffuse green auroras' should be used for isolated hazy green blobs/arc.

      Matias Takala, RAGDA
      Dunes in RAGDA's green aurora
      Photo: Matias Takala


  • 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.

    • Fully red auroras info

      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.

Technical information

Canon EOS 6D, Tokina 16-28mm ISO 3200-6400, f2.8, 3-15s

Comments: 5 pcs
Jorma Koski - 25.10.2017 at 16.00 Report this

Hienot kuvat taas ja varsinkin SAR!

Anne Eränotko - 25.10.2017 at 16.21 Report this

Että saa tällaista luonnon mahtavuutta ja häikäisevyyttä nähdä ja ihailla! Pirjo Kosken loistokkaat kuvat lumoavat jälleen. Oma tenhonsa on myös hänen liitekirjoituksissaan.

Pirjo Koski - 25.10.2017 at 17.11 Report this

Kiitos Jorma ja Anne :)

Marko Pekkola - 26.10.2017 at 11.04 Report this

"ja sitten punaiset, etelässä tanssineet tulet vihreine läiskineen." 

Pirjo, ymmärränkö oikein, että nuo punaiset nauhat/kaaret/alueet liikkuivat selvästi havainnon aikana, mahdollisesti jopa syttyivät näkyviin ja sitten katosivat? 

Pirjo Koski - 26.10.2017 at 11.40 Report this

Marko, tuo oli minulta hivenen harhaanjohtava lause, pahoitteluni siitä. Eli nuo vihreät revontuliläiskät kirkastuivat ja lopulta haalistuivat pois, jättäen punaiset tulet jäljelle. Punaisten tulien keskeltä nousi punainen kaari/nauha joka pomppasi esiin, välillä se ikäänkuin haalistui, välillä kirkastui, mutta pysyi koko ajan paikallaan. Pilvet haittasivat koko nauhan/ kaaren havainnointia, mutta se oli kokonainen, hurjan korkea nauha, -samanlainen kuin silloin pari viikkoa sitten havaittu nauha / kaari, miksi sitä nyt pitää luonnehtia. Muut revontulisäteet "harso" häälyivät taustalla kuten kuuluukin, haalistuen lopulta olemattomiin. Punainen kaari vaan oli ja pysyi. Lähtiessäni kotia kohti se vesseli oli vielä paikoillaan, mutta todella vaaleana nauhana, kunnollisia kuvia siitä ei enää saanut. Jos pitää vielä yrittää kuvailla kaarta/ nauhaa, se vaikutti olevan "irti" kaikesta muusta näytelmästä. Paremmin en nyt pysty sitä kuvailemaan.

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