On 20th March 2015 we could witness one of the most spectacular phenomenon in the Solar System, the total solar eclipse. The track of totality passed across the North Atlantic and next headed into the Arctic Ocean. This eclipse used to be a logistical nightmare to observe, because the only populated places from which the totality could be seen were the Faroe Islands and Svalbard.

The breadth path of totality passed tantalisingly close to the south east Iceland, where people experienced around 99,5% partial eclipse and were able to see the Moon’s shadow on the high altitude clouds beyond. The path of totality almost touched the Rockall islet the westernmost point of the Brisith Isles and the South-east corner of Iceland (Djupivogur and Breiddalsvik), where the distant was 37km only.

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Pic.1 The map of the TSE 2015 eclipse magnitude (greatamericaneclipse.com).

Many tourist agencies and private organisators decided to chase this eclipse due to location between high developed areas (mainly European Union). Unfortunately the track of the totality was not passed favourable. The area of North Atlantic, which is fed from the Golfstrom current is characterised by a few degrees warmer water. Thanks to this this region is a real hot bed for low pressure systems and nice route for huge windstorms headed for north and central Europe. It incurs a big cloud coverage across the region and high precipitation.

The best places to see the almost total solar eclipse were: north west Norway (Lofotes), south Iceland and north Scotland (Shetland Islands, Orkeney Islands, Outer Hebrides and Highlands Region). There are locations, where Moon covered more than 96% solar disk (Pic.1). Taking into account the Sun altitude during the eclipse the best places to go were Lofotes, Faroe Islands and north west Scotland (Pic.2).

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Pic.2 The map of the TSE 2015 Sun altitude (greatestamericaneclipse.com).

During this obscuration the solar corona becomes possible to see, however it is barely visible for eagle eyed observators. This situation is possible, because the solar corona is nearly the same bright as an full Moon (0.23 full Moon light, something around -11mag). Taking into account the bright of Venus (-4,5mag), which is visible on the sky during the day the solar corona would be visible also, though it must be outside the Moon’s limb and this is possible just around the annular, hybrid or total solar eclipse. By the other hand during this level of obscuration the sunlight density is around 24x lower than usually. In higher obscuration this effect is stronger, up to totality, when the coronal streamers are clearly visible. From this locations was not a place guaranting a good weather during this occurence. Everybody, who decided to take part in this natural phenomena both in the path of totality and the locations listed above would expect truly differend kind of weather. It was a cropshoot.

I was looking forward the 2015 solar eclipse since winter in early 2011, when I took a small observation of the deep partial solar eclipse in Krakow. Basically I dreamed about the Spitsbergen expedition, seeking for people and astronomy clubs, who could go there. Many people realized, that organisation of this scounting trip will be very expensive and quite pointless due to weather conditions. Finally I couldn’t find a group, which I would go with. Meanwhile my situation has been changed due to emigration. I started to live in Great Britain since february 2015.

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Pic.3 Partial solar eclipse on 20.03.2015 across the UK & Ireland (britastro.uk)

Despite of this difficult challenge I never gave up and I decided to organize this “expedition” on my own. Because of the weather conditions I choose the closest and the cheapest way to see this eclipse. I wish I could go to the Iceland, Faroe Islands or Spitsbergen, but always when I decide to go somewhere I would very much like to see some remarkable spots. In this case it could not be really possible due to the weather. Hence I decided to go as close as possible from my location – to north Scotland. On top of that the acommodation in the path of totality and the deepest eclipse had been booked many time in advance and only some the most expensive left.

I was considerating to visit the Outer Hebrides and watch the almost total solar eclipse from there, but finally I decided to stay on the scottish mainland. Despite of a little bit lower eclipse magnitude I could always go somewhere else, catch the better weather and visit some interesting places.

The weather situation around March 20, 2015 wasn’t good in north west Europe. It was a few cyclons, which went one by one by through the east Atlantic Ocean and Norwegian Sea towards Scandinavian Penninsula. The chances to see this beautiful phenomena were very low, because mostly the sky were covered by at least 2 layers of clouds. When I was checking the weather satellite imagery, the sunny spells were visible only somewhere above the sea. Just a few days before the eclipse the weather forecast in United Kingdom wasn’t so good also. They predicted a lot of sun for the southern part of Britain, Ireland and south Scotland. Regrettebly the area of the deepest eclipse was going to be the most rainy in the whole UK. This forecast didn’t deter me. I came to conclusion, that it will be good to have from this observation anything. I planned the light density change observation anyway, so in the worst case the good weather was not required. However it was really good to have as best weather as possible to see the whole eclipse effect.

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Pic.4 The TSE 20.03.2015 and cloud coverage above the Europe (eumetsat.int).

We set from Cambridge on Wednesday March,18 in late afternoon and after full one day journey (via London, Edinburgh and Inverness) we came to Ullapool on Thursday March 19, at 19:00.

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Pic.5 the TSE 2015 and place of my observation (marked black) (based by eclipse.gfsc.nasa.gov).

Thursday night was a nightmare for me. I was tossing and turning all night long and watching the most actual infrared weather images. It weren’t optimistic, because rainy fronts were coming towards Scotland one by one.

Friday’s dawn was really bad. I could hear passing downpours through the window. My girlfriend said: “If you had stayed in Cambridge you would make the observation, but here you will have nothing”. Despite of the fatal weather conditions I decided to leave our hotel quite early, around 7:00 and go ahead heading north-west.

Ullapool is a small ferry town in western part of Highlands region. The climate of this place is amazingly warm. There is even 1 palm tree, but I couldn’t see it due to bad weather and lack of time. Anyway the townscape is really nice (Pic.7). In this area rain takes hold all year round and it’s hard to enjoy really good weather.

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Pic.6 Ullapool ferry at the time, when we arrived (Thursday March 19, 19:00 UTC).
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Pic.7 Ullapool, Quay street urban area.

When we left Ullapool, the weather started to improve. The thick dark clouds gaves a way for sunny spells and patches of blue sky. After around 20 minutes way in Drumrunie we turned left into Achnahaird. This way was really narrow and difficult to beat due to many bends and sheep coming constantly across the road (Pic.8).

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Pic.8 Sheep standing on the narrow way towards Achnahaird.

I chose this route, because I saw a wide patches of clear sky above the west horizon.               I though, that rainy front is definitely gone and weather will be improving. I was going to image the north west horizon and catch the Moon’s shadow passing through the ocean. First I had to cross the Cul Mor community to see the most lower horizon with sea. When we passed those tors then, we stopped on the heather-clad area with a far-realing view on the sea and remote another part of British mainland beyond (Pic.9,10).

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Pic.9 Extended heathland in the vicinity of Achnahaird with view towards the Cul Mor community (far beyond).
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Pic.10 Extended heathland in the vicinity of Achnahaird with view towards the Loch Garvie Bay.

I was really happy, because weather were improving. I could even see a first shaft of sunlight just after the thick low-level clouds. I started to observe the eclipse from there. Unfortunately this place wasn’t good, because the sunny spells coming from the seaside were dissapearing above Caledonian’s Mountains hillsides behind our back above south east horizon. Besides we witnessed one short rain shower. After 15 minutes I decided to change the observation place and go forward around 2km, where weather seemed to be better.

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Pic.11 The cloud coverage above the sights (marked red) considerating by the best to chase the solar eclipse 20.03.2015 (sat24.com).

There I continued the observation. Everything was fine, the eclipsed sun was shining and I could carry out my duty. Unfortunately 15 minutes before the greatest eclipse the weather was worrying again. I saw a huge cloud coming directly to sun. Afterwards started raining. I saw a crescent Sun 6 minutes before the maximum. It got me very dissapointed, though in the vicinity, above north west horizon a huge section of clear sky was passing by. I saw a remote another part of British mainland, which was sunlited. I could see a Moon’s shadow also. Next the huge rain swept across the our site and crescent Sun was gone until 10:10, when was completely bright. In general I did mistake, because if I had known that it is going to be like that I would have gone to Lochivner and try to set in the near villages situated on the another part of Scottish mainland. In this case I could see clearly the greatest eclipse, but possibly without the north western sky, because I saw another clouds just behind the clear section of sky (Pic.12).

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Pic.12 Cloud coverage (grey) during the greatest eclipse around our observation sight (green arrow). The Lochivner surroundings with the Stoer Lighthouse (green rope), seen from the place of observation (based by scribblemaps.com) was free of clouds. I made this image on the base of images captured during the eclipse (see also Pic. 37-45, 48).

From my site I could only see the diminish sunlight over there, which gave prominence for local lighouse (Stoer Lighthouse), much brighther during the greatest phase. It was exactly 295km to path of totality from my place (Pic. 13,14).

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Pic.13 The distance to the path of totality from my observation sight.
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Pic.14 The range of sight during my observation the eclipse from north Scotland.

The observation

My basic goal during this almost total solar eclipse was watching the decreasing density of light. I imaged this phenomenon in four directions:
South east (Sequence A), towards the eclipsed Sun (Pic.15),

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Pic.15 View towards south east.

west (Sequence B) in order to capture the darkening sky before the maximum eclipse (Pic.16,17),

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Pic.16 View towards west with Loch Vatachan lake.
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Pic.17 View towards west with Achnahaird and Loch Ra lake (after changing the position).

 north northwest (NNW) (Sequence C), opposite to the crescent Sun, in order to chase the Moon’s shadow in the Earth’s atmosphere (Pic.18,19),

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Pic.18 View towards north northwest (NNW), the Loch Garvie Bay beyond.
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Pic.19 View towards north northwest (NNW) after changing the position, Allt Loch Ra rover and Achnahaird Bay in the background.

Another part of my documentation was comparison the eclipsed sunlight with the car bulbs (Sequence D). I was founded, that during the 90% partial phase the sunlight is nearly equal the car headlight. In that moment the Sun was clearly visible yet (Pic.20).

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Pic.20 Comparison the sunlight (green arrow) and Honda dipped headlights (red arrow) during the magnitude 0,9 (obscuration 89%).

I made photos with exif data as follows:

Sun: 1/6000s, ISO 80, F5.6

Sky: 1/125s, ISO 80, F 3.4

Greatest eclipse sky: 1/25s, ISO 80, F 4.5 (some photos only)

Camera: Canon Powershot SX130 IS

To make an overall I bracketed the photos in each sections. Let’s describe those sections then:

Sequence A:  Contrasting all bracketed photos a big difference may be noticeable with obscuration 63% and higher. Due to increasing cloud coverage this observation wasn’t conticued (Pic.21-24).

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Obserwacja A Zacmienie widok SE
Pic.21-24 Observation the intensity of light changes towards south east (eclipsed sun). 21- Obscuration 19%, 22 – Obscuration 63%, 23 – Obscuration 76%, 24 – Bracketed photos, from the left: 8:30 UTC, 4%; 8:48 UTC, 14%; 8:52 UTC, 19%; 9:16 UTC, 63% and 9:21 UTC, 76%.

Sequence B:  View towards west, from where the eclipse were coming. Darkening is visible from 63% obscuration, like below (Pic.21-24).

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Pic. 25-28 Observation the intensity of light changes towards west: 25 – Obscuration 14%, 26 – Obscuration 71%, 27 – The greatest eclipse obscuration 97%, 28 – Bracketed photos.

Sequence C:  The darkening sky is visible when the Moon clips more than 50% solar disk. When the obscuration is higher than 90%, the sky is much more darker and the view changes rapidly (Pic.29-32). According to the picture attached sky is more dark on the left side (more above west horizon). Actually the Moon’s shadow was there.

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Obserwacja D ver.1
Pic. 29-32 Observation the intensity of light changes towards north northwest (NNW): 29 – Obscuration 30%, 30 – Obscuration 63%, 31 – The greatest eclipse obscuration 97%, 32 – Bracketed photos.

Sequence D: Car’s headlight is equal with sunlight during the obscuration around 90%. Once the partial eclipse is deeper, the headlights may be stronger than sunlight. This is unfortunately not proved, because of clouds coverage (Pic.33-36).

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Pic. 33-36 Comparison the Honda’s dipped headlights with the eclipsed sunlight: 33 – Obscuration 71%, 34 – Obscuration 95%, 35 – Greatest eclipse obscuration 97%, 36 – Bracketed photos.

Thanks to the elongated clear gap passing above the north west horizon I could insightfully analyse the Moon’s shadow movement (Pic. 37-44). As I noticed, the best moment to observe the shadow was just after the greatest eclipse. Then sky above nortwestern horizon were dark blue. Moreover you may be able to see rough border of the shadow in the cropped images (Pic. 43,44).

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Pic. 37-40 The Umbra edge above the north northwest horizon (green arrows and brackets): 37 – Obscuration 95%, 38 – Greatest eclipse obscuration 97%, 39 – Obscuration 96% after the maximum phase, 40 – Obscuration 89% after the maximum phase.

I was really surprised, when I spotted suddenly darkening sky just above clouds (Pic.40, green arrow) 7 minutes after the greatest phase (magnitude 0,9, obscuration 89% !).

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Pic.41-42 Moon’s shadow seen from northern Scotland (green arrows, green bracket): 41 – Obscuration 91%, no shadow visible above north western horizon; 42 – Moon’s shadow visible on the left side, just behind small rainfalls).
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Pic.43 Moon’s shadow seen during the greatest eclipse (green arrows) comparing with sunlited sky on the right (yellow thick arrow)
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Pic.44 The umbra was fully visible just after the maximum ecipse (green arrows).
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Pic.45 Umbra spotted las time at 0,9 Magnitude, not seen anymore (as per as lower part of the image).

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Pic. 46,47 Umbra seen during the greatest eclipose above north west horizon with exposure 1/25sec.
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Pic.48 Zoom into north northwest horizon, when umbra was seen in the atmosphere (green arrows). Look at another part of mainland with Stoer Lighthouse marked with grey arrow and grey circle. The distant from my observation sight to that place was 20km. Near the Stoer Lighthouse the Sun was shining for entire eclipse!
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Pic.49 The image compilation with 1/25 sec exposure to compare the intensity of light during the maximum eclipse, 95% obscuration and full Sun (2 days later in Edinburgh) on the bottom right.

Conclusions:

Before  I saw this almost total solar eclipse I was considerating some issues. I could prove some of them, making this observation. All conclusions are listed below:

1) During the partial solar eclipse with obscuration higher than 50% (magnitude 0,59 (we are able to see darkening of sky, especially on the opposite site to the Sun.

2) When eclipse obscuration is higher than 50% you may see difference in the sunlight density by naked eye on your observation site.

3) When obscuration is higher than 75% sky, the scene is darkening faster. We can then say, that we are experiencing a deep partial solar eclipse.

4) During the deep partial solar eclipse with magnitude 0,9 and higher (obscuration 89%) sky becomes dark blue, the animals may be concerned. The light density is mor or less alike during cloudy day.

5) When magnitude is 0,95 or higher it may be needed use dipped headlights in the car and switch indoor. The observator may witness twilight.

The eclipsed Sun

I was able to see crescent Sun until 9:30 UTC. It was quite easy to capture pictures, because the clouds veiled the solar disk and created natural filter.

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Pic. 50 Crescent Sun around 9:20 UTC seen through the filter.
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Pic.51 Crescent Sun after 9:20 UTC.
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Pic.52 The eclipsed Sun around 9:25 UTC.
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Pic.53 The eclipsed Sun at 9:28 UTC
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Pic.54 Mid-level clouds covered the Sun around 9:30 UTC.

It was an amateur observation only. I hope, that to be continued in the future. Despite of the bad weather this “expedition” was well worth the effort. Unfortunately I chosen the worst option due to weather. As I saw afterwards in every different location called in this article weather was better. Even across the Faroe Islands, where chances for sunshine are very slim (merely 6% days per year) people could enjoy this remarkable phenomena. Scotland unfortunately was cloudy and rainy with some elongated sunny spells. The weather on the Outer Hebrides, where I was considerating to go were very similar. I did very good, that I set out from Cambridge. There, as one member of Cambridge Astronomy Association said the Sun was out just before end of the eclipse. A thick fog covered East Anglia for entire morning hours. I did also well with renting a car, because the weather in Ullapool were much worse. I hope, that next solar eclipse expedition will be much more succesfull.

After the eclipse we back to Ullapool and carried on the trip across north west Scotland. I will elaborate more about this in the next article.

Mariusz Krukar

References:

  1. Sytinskaya N.N., Sharonov V.V., 1963, Measures of the brightness and color of the solar corona studied at six eclipses, (in:) The Solar Corona; Proceedings of IAU Symposium no. 16 held at Cloudcroft, New Mexico, U.S.A. 28-30 August, 1961. Edited by John Wainwright Evans. International Astronomical Union. Symposium no. 16, Academic Press, New York, 1963., p.301

Links:

  1. Stevens L., Totality – The digital magazine for eclipse chasers, 2016, Issue 14

Foogates:

  1. https://www.youtube.com/watch?v=hNM95J8Nb3w – almost total solar eclipse above Isle of Lewis
  2. https://www.youtube.com/watch?v=vaKeiXpBlt8 – almost total solar eclipse in Stornoway
  3. https://www.youtube.com/watch?v=eL3GU2JDMjs – TSE in Faroe Islands
  4. https://www.youtube.com/watch?v=dRAkhQ6CfmA – TSE in Svalbard
  5. https://www.youtube.com/watch?v=PFycHsyyGS0 – deep partial solar eclipse from North Queensferry (Scotland)
  6. https://www.youtube.com/watch?v=feR12pQ8dXc – Hamferð – Deyðir varðar (live during the solar eclipse in The Faroe Islands, March 20th 2015)
  7. https://www.youtube.com/watch?v=QvEpvMK9BTc – TSE 2015 from the plane
  8. https://www.youtube.com/watch?v=CHapz-kPL5k – almost total solar eclipse in Iceland (part 1)
  9. https://www.youtube.com/watch?v=nrkwEPA7hLw – almost total solar eclipse in Iceland (part 2)
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