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

Ursa Astronomical Association

Active aurora band - 10.9.2018 at 22.00 - 11.9.2018 at 01.00 Kontiolahti Observation number 77529

Visibility III / V


The traditional opening of the holiday season in Häikänniemi.

During the early fall, I changed my camera equipment from a full frame (Nikon D750) to a mirrorless body camera Fujifilm X-T2 and I've been impatiently waiting to test the frame and Samyang's 12mm f2 lens with the repo people as well. Now there was finally a chance to do it, with quite handsome lights blazing in the sky, but it didn't go exactly as it was supposed to.

I tested various settings and wireless data transfer from the camera to the computer and mobile devices from early evening at home. It turned out that with regard to raw images, wireless data transfer is not possible with the mobile application provided by the manufacturer, so I did various tests during the evening to resolve the issue.

The forecasts promised such a high level of activity that the test exposures taken after nightfall really put a smile on my face and I drove the car to Höytiäinen beach. The idea was not to look for a new or special place, but specifically to test the camera and Samyang's 12mm f2 lens.

After I got to the shore, the northern sky immediately began to brighten up the aurora borealis and quickly move, and I moved the camera with the tripod to almost the first possible place. Clearly the first successful repo meal of the fall, judging by the enthusiasm...

The settings are more or less correct and the shutter starts to sing. The situation continued for almost half an hour and I sometimes changed places to the other side of the thin isthmus of Häikänniemi.

After less than half an hour, the situation started to calm down and I looked through the pictures I had taken... to find that jpeg pictures were taken, and not even in full quality. Since I normally always keep the settings on RAW, it didn't even cross my mind, and I didn't routinely see it on the camera screen.

However, the positive aspect is that the jpeg images turned out to be reasonably decent, even though there is no room for adjustment, especially in the shadows. There was more room for adjustment in the raw photos taken later in the evening.

Samyang's 12mm f2 for a body scan seems to be quite a sharp glass already at full aperture. It would seem that the difference between the combination and the former full-cell system is by no means huge, as long as you remember to expose correctly.

I will continue to practice...



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.

    • 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.

    • 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
      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.

    • STEVE-arc info

      STEVE (Strong Thermal Emission Velocity Enhancement) is an aurora-like phenomenon that can be observed in middle latitudes. STEVE does not belong to traditional auroras as a phenomenon, but may appear at the same time with them.

      STEVE looks like a narrow, white or mauve arc that is clearly separate from the rest of the aurora oval in the pole-ward side of the sky. In Northern Europe, STEVE can sometimes be seen quite far from the oval and be visible across the southern half of the sky.

      STEVE, Keijo Lehtimäki
      A mauve STEVE with a clear gap to the oval. Image: Keijo Lehtimäki

      It forms a long and narrow east-west aligned dim line that goes across the night sky. The length of the arc can be over 2 000 km and it is located at altitudes of 110-300 kilometers.

      The best time for observing STEVE is when the active aurora of a substrom have subsided.

      The arc is white, grey or light purple in color, but the appearance of the arc may vary slightly. In more colorful versions, the bottom edge of the arc shows while/grey color, whereas the upper part has more purple shade. These colorful versions are called Double-Layer STEVE.

      Double layer STEVE, Eero Karvinen
      Double-Layer STEVE. Image: Eero Karvinen

      STEVE's appearance can resemble single, detached rays or there can be rays within the arc itself.

      Riku Talvio, STEVE
      A ray-like STEVE. Photo by: Riku Talvio

      Quite often purple rays within the aurora oval itself get mistakenly identified as STEVE. While within the aurora oval the purple rays tend to disappear relatively fast, STEVE-events can last from ten minutes to hours.

      STEVE very rarely shows green color, whereas lower edges oval's traveling rays tend to be clearly green. However, occasionally there may also be a green, "toothed" band called ”picket fence” below and aligned with the STEVE arc.

      Sirpa Pursiainen, STEVE picket fence
      STEVE with picket fence. Image: Sirpa Pursiainen

      SAR arcs are a different phenomenon happening in the same region that sometimes gets mixed up with STEVE. SAR-arcs, however, are more diffuse, dimmer or fainter, purely red, and lasts longer than STEVE, even days.

      Atacan Ergin, STEVE SAR
      This rare image shows a red SAR-arc with a white STEVE arc. There is an area without aurora light around STEVE. Image: Atacan Ergin

      When photographing a suspected STEVE, it is important to try capturing both the arc form and the arc's location in relation to the rest of the oval.

      In some cases, fine westward-moving structures can be observed within the arc. These can be captured by taking videos of the event or capturing short-exposure animations.

  • 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.

    • 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.

Comments: 6 pcs
Matti Helin - 12.9.2018 at 15.26 Report this

Hienoa jälkeä.

Karri Pasanen - 12.9.2018 at 15.44 Report this

Kiitos! Näköjään giffit eivät toimi kaikilla selaimilla...

Heidi Rikala - 12.9.2018 at 16.06 Report this

Upeat reposet ovat olleet. hienot kuvat ja viedot.

Arto Paakkunainen - 12.9.2018 at 18.33 Report this

Onko häikänniemestä? Itse Joensuusta ja oli hilkulla että lähden häikkään katselee että näkyykö reposia yms mutta väsy iski:)

Emma Bruus - 12.9.2018 at 21.31 Report this

Huikea tuo eka animaatio!

Seija Hakala - 16.9.2018 at 09.57 Report this

Kiitos kyttäyspaikkavinkistä ! Olin sukulaisvierailulla Joensuun kupeessa ja halusin myös kuvata reposia . Seutua tuntemattomana en ilman vinkkiäsi olisi sopivaa paikkaa löytänyt.

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