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Ursa Astronomical Association


Skimpy rainbow spring's show in the evening of

30.5. Markku Ruonala tells in his rainbow observation on 28.5. the supply of the phenomenon has been on the cards this year. Skywarden's statistics agree. From 2012, in the period from 1 January to 28 May, rainbow in Finland has been seen on maximum of 20 days (2016), minimum of 10 days (2013 and 2019). This year only 8 rainbow days were reported on this period.

Subsun from wingsuiting jump

28.5. Glories and fogbows are the basic imagery of wingsuiting. A rarer prop is represented by the bright subsun that Vesa Toropainen saw above Utti on 27 May. This was made possible by the jump taking place over a crystal cloud that had been left over by a dead rain shower cloud.

The most summery aurora borealis on July 2000

27.5. Jorma Koski left a report about the aurora borealis he saw on 16.7.2000 in Porvoo. At the time the pictures were published in SpaceWeather on the same day. Their occurrence 596 hours from the summer solstice (according to 1:00 a.m.) single-handedly improves "the most summery" record for the Finnish northern lights in Skywarden, which has been 912 hours (July 29, 2016). The aurora were of the most powerful G5 category. "My head spinned like a top", Koski says.

Fireball on Tuesday night

24.5. A fireball that flew at 23:44 on Tuesday was spotted west of the Kokkola-Jyväskylä-Kotka line. Fifty sightings have so far arrived at the Skywarden. The attached screenshots are from Juha-Matti Kaataja's car camera video. Juha Ala-aho in Vaasa didn't manage to photograph the fireball, but captured its smoke trail with a mobile phone. "The smoke was visible for two minutes before it completely dissipated," he says.

Protuberance extends on the edge of the Sun

24.5. Another quality view to our central star, this time by Samuli Vuorinen, who in Kirkkonummi took on Monday his Lunt LS50THa telescope and a Player One Neptune-M camera to photograph a long protuberance. "I started the timelapse shooting on the balcony while continuing to do remote work at home," he writes. In Vuorinen's observation is a video of the situation.

No noctilucent clouds yet

24.5. The night cloud season usually starts in June in Finland. Statistics dating back to 1995 show that, on average, every third year the start takes place in May. Pentti Arpalahti scanned the Helsinki skyline with his camera on the 23/24.5 night. Below 10 degrees, there is streakiness, which cannot really be interpreted as NLCs and is more naturally explained by distant dust-cloud and cloud layers, he writes in the negative observation he left in the system.

Protuberances in excellent condistion

20.5. Good sun weather continues. Top notch seeing in the morning of 19.5 allowed Ben Kalland to use the maximum focal length in Porkkala to capture the protuberances of the Sun. "Two arcseconds seeing is good, if you go over that the image starts to vibrate in front of your eyes," writes Kalland. In this session, the Solar Scintillation Monitor measured minute averages below 1 and momentarily 0.25. Also in Tampere Tapio Lahtinen photographed the sun later in the day.

Strong Wegener arcs in Oulu

19.5. May continues to churn out quality halo displays. Now it was Oulu's turn, where Lauri Kangas was alert when the halos suddenly appeared in the sky shortly before nine in the morning. On the opposite side, we see Wegener anthelic arcs, and in the post-examination a subhelic arc, that diagonally intersects the 120° parhelion, was also found. A better-than-usual set was also offered in Kurikka in the form of almost full tanarc.

A medium-sized flare in the Sun

18.5. Of course, the sun is closely monitored by the Skywarden watchmen, and sometimes seeing allows for better shots than usual. In Porkkala in the morning of 18 May the atmosphere was calm as Ben Kalland photographed the spot regions. In this image, where the Sun's surface is almost palpable, a C-class flare erupts from the spot region AR3310. Kalland says that an hour later a larger M-class flare was seen, which he did not manage to photograph.

Subhelic arc on 17.5 in Juva and other halo shows

18.5. Petri Martikainen photographed a display in Juva on Wednesday with an all-sky lens for 10 minutes and got Wegener arc and subhelic arc (arrows) out of the stack. The latter is already a respectable catch. The full circumscribed halo that Martikainen caught the day before is not bad either. Third from the Juva halo observatory is the stack of the 11.5 display, which shows e.g. 24° plate arcs and segments of the associated halo.

Spring dust swirls in the fields

16.5. Dry and sunny days have warmed the air above the ground, creating swirls of dust. Pia Simonen videoed a one in Orimattila on the 11th. Two days later, an anonymous person recorded a dust devil in Karkkila with a drone. It lifted up a piece of plastic covering the field.

Skywarden's latest aurora borealis

14.5. Terhi Törmälä's faint aurora rays half an hour after midnight on 14.5 in Lappeenranta moved the phenomenon's Finnish lateness record in Taivaanvahti forward five nights. If on the other hand we look at what is the most summery observation, then Pirjo Koski's and Matti Helin's reports of July 29 2016 northern lights take first place. They saw aurora 912 hours from the summer solstice versus 930 hours for Törmälä's, which were too dim for visual.

A curious colored cloud and reflection subsun

14.5. Pia Simonen published a picture from May 13 of a tuft of irisdescent cloud she saw. Its exceptional fibrous structure was also noted in comments. A second reflection subsun of the year was caught on May 10 in Tampere. "The clouds, the sun and the calm surface of Lake Näsijärvi were just right during the morning coffee," writes Ilpo Hyvärinen, who left the observation. Spotting the reflection subsun really requires several factors to fall in place.

Halos in the spring sky

11.5. Alonside the warmer weather better than usual ice crystals populated the upper troposphere. In Turku halos from pyramidal crystals were visible on 9.5, the display in Mikko Peussa's photo is dominated by 18 halo and 23° parhelia. The next day was the turn for more traditional complex without odd radius halos. Several sightings have arrived, the best going was in Tampere, where Ville-Aleksi Alatalo took the other shown photo.

Late aurora borealis in Turku

9.5. There are fewer sightings of aurora in May in Taivaanvahti. Mikko Peussa's observation last night in Turku equals the observation system's latest sighting from 2014. At that time the northern lights were photographed in Kempele and Kuusamo where the night sky is brighter. The skies of southern Finland should therefore allow still to stretch the season a bit further. "Maybe a few more nights, but that's it," writes Peussa.

Birch pollen ring and 9° column arcs

9.5. From when the first pollen corona was seen on 7.4. they have been reported about every 10 days and it is not clear at what point the alder changed to birch. Now we are firmly on birch. Attached are pictures of Paula Mattila and Markku Siljama from 7.5. in Turku and 8.5 in Mäntyharju. On 7.5. Olli Sälevä photographed the rare 9 ° column arcs in Rovaniemi and Petri Martikainen saw parhelia in Juva.

Maintenance break coming on Tuesday

Tuesday 9.5. from 6 p.m. maintenance work will be done at Skywarden. In this context, the system is temporarily unavailable. The changes aim to improve the performance of the observation service during momentary load peaks during sky phenomena. Due to the maintenance break, the accessibility of the system may still be disrupted on Wednesday.

The lunar eclipse was visible in Ulvila

7.5. Penumbral lunar eclipse remains was visible on Friday evening. "The moon would rise only after the deepest phase, so visibility would require an unobstructed southeast horizon and clear weather," writes Jarkko Laukkanen, who went to the Ulvila observatory with friends to try the event. Although clouds were present, the eclipse could be seen: there was a noticeable difference in brightness between the upper and lower part of the moon, Laukkanen tells.

Rainbows and halos in the spring sky

3.5. The first rainbows of the year were seen on 1.3. and 12.4. and more came at the end of last month. The upper photo was taken on 30.4. by Aarne Hagman in Savonlinna, lowerby  Mervi Juntunen in Mikkeli. The lower one of the halos on the right was captured by Sebastian Sainio in Mustasaari on 3.5. The sky is cut by parhelic circle, which has 120° parhelion as brightening. The parhelion above it was captured by Matti Puranen on 29.4. in Mikkeli.

Early water surface dewbow in Lappeenranta

30.4. Risto Vättö saw rainbow colors on water in Lappeenranta on April 27. This is a short segment of dewbow, the relative of rainbow. On the water surface lies a raft made of some kind of substance on which light-refracting and reflecting water droplets have condensed. The typical time is July-August. That is when a lot of different stuff floats in the water, such as insect shells. The best dewbows are seen in the spore floes of the irregularly occurring Chrysomyxa ledi needle rust.