Solar eclipse in St Andrews – Yes, we saw it!

The day had come; the 20th March was the day people all around Europe had been waiting for, the day of the solar eclipse. For most of the people, this is a once-in-a-lifetime event. To see an almost total eclipse is a very exciting thing! The Moon passing in front of the Sun, covering its full disk happened this time too, however only the lucky few were able to see it from the scene, since the track of the totality covered mostly the Norwegian Sea.

In St Andrews we were watching the weather forecast since Monday, to see how the weather changes; if we would have a nice, clear sky on Friday, even though we knew the weather here changes from hour to hour, making it impossible to predict it properly days before the event. It didn’t seem good, especially at the beginning of the week. By Thursday it cleared up a bit, however, by the end of the day new clouds covered the sky.

The crowd of excited people in front of the PandA building (Credit: Wendy Clark)

The crowd of excited people in front of the PandA building (Credit: Wendy Clark)

Where did the Sun go? A minute ago it was still here! -- No worries, we found it! (Credit: Wendy Clark)

Where did the Sun go? A minute ago it was still here! — No worries, we found it! (Credit: Wendy Clark)

On the morning of the solar eclipse, half an hour before the event, it was still pending if we would be able to see it: half of the sky (towards the east), was cloudy, while the other half was clear. But we were optimistic. Some of the enthusiastic PhD students and stuff members set up three telescopes in front of the Physics and Astronomy (PandA) building of the University of St Andrews. The two 8 cm telescopes (Meade ETC 80) were equipped with solar filters and cameras, one of which was connected to a tablet. The third telescope (Maksutov-Cassegrain, ~8 cm) was an older set up: it projected the Sun on a white plate (projection screen). We were ready for the big event.

And we were lucky! The sky cleared up! The clouds only bothered for a couple of minutes. We saw the eclipse from the beginning to the end. In St Andres the Moon covered about 95% of the Sun, which resulted in a slightly darker daytime around the maximum of the eclipse. It started at 8.31 with maximum at 9:36 finishing at 10:45. The event drew the attention of the public too. Families with children, students and stuff members, residents of the town came along to watch the eclipse with us. At some point a TV screen appeared, which was connected to the other camera, satisfying the popular demand.

The Maksutov-Cassegrain telescope in action. (Credit: Wendy Clarke)

The Maksutov-Cassegrain telescope in action. (Credit: Wendy Clark)

At the meantime, the totality was streamed in one of the lecture theatres inside the building. By the time the Moon covered the full disk of the Sun, the lecture theatre was crowded by people, who were about to see what the visitors and inhabitants of Svalbard could see: a beautiful diamond ring around the fully covered Sun.

Eclipse starting, with a 'tiny' sunspot on the bottom right third of the Sun. (Credit: Josh Argyle, Gabriella Hodosán, Milena Pawlik, Gabriella Hodosan, Victor See, David Starkey  (Astronomy PhD students of the University of St Andrews))

Eclipse starting, with some clouds and a ‘tiny’ sunspot on the bottom right third of the Sun. (Telescope: Meade ETC 80 mm refractor, Camera: Canon EOS 1100D) (Credit: Josh Argyle, Gabriella Hodosán, Milena Pawlik, Gabriella Hodosan, Victor See, David Starkey (Astronomy PhD students of the University of St Andrews))

The event was successful. The weather was kind to us, we had a sunny, warm morning, perfect for eclipse watching. The next eclipse, with similar (>90%) coverage will be visible from the UK in 2026.

Solar eclipse seen from St Andrews. (Credit: Josh Argyle, Milena Pawlik, Gabriella Hodosan, David Starkey (observing and photography), Victor See (editing))

Solar eclipse seen from St Andrews.
(Credit: Josh Argyle,  Gabriella Hodosán, Milena Pawlik, Victor See, David Starkey (Astronomy PhD students of the University of St Andrews))

 

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Aurora Borealis – The play of colours over St Andrews

During the night of 27 February, 2014 a rare phenomenon took place on the sky of St Andrews. Around 10 pm the lucky ones saw the amazing red and green splendour of the Aurora.

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Red and green lights of the Aurora Borealis with the Castle of St Andrews in the front. (Credits go for Pasquale Galianni, astronomer of the University of St Andrews)

Red and green lights of the Aurora Borealis with the Castle of St Andrews in the front. (Credit: Pasquale Galianni)

Everyone heard of the bright, dancing, colourful lights of the Aurora Borealis. Some have seen it by their own eyes, others have seen breathtaking pictures of it. But what is the Aurora exactly?

The Northern Lights are natural light phenomena, which occur at high latitudes on both hemispheres of the Earth (called Aurora Borealis on the North and Aurora Australis on the South). It is the result of the collisions of charged particles coming from the Sun as solar wind and the upper part of a planet’s atmosphere.

In the upper corona of the Sun the velocity of the thermal motion of the particles become higher than the escape velocity. This results in a continuous material loss from the Sun in the form of solar wind. These charged particles (ions and electrons) hit the Earth’s magnetosphere and tie to it. The magnetosphere accelerates some of these particles towards the Earth’s surface. As they reach the upper atmosphere they collide with atoms and molecules releasing kinetic energy, which we is seen as the lights of the Aurorae. The more active the Sun (which means more solar wind) the more frequent the Aurorae.

The colour of the lights depends on the atom/molecule the energetic particle collides with. The most commonly seen type is the green Aurora. At mid altitudes (~ 100 km), where the concentration of oxygen atoms is fairly high, the collisions between atoms and ions/electrons releases energy at ~560 nm, which is in the green part of the spectrum. At the highest altitudes (up to ~300 km) the oxygen atoms emit around 630 nm (red part of the spectrum). Because of the lower concentration of the atoms in this part of the atmosphere, red Aurorae are seen very rarely and only when the Sun is around its activity maximum. The blue colour is the result of the collision with molecular nitrogen. This takes place at lower altitudes, where the amount of atomic oxygen is reduced.

Aurora Borealis seen from the Observatory of St Andrews. (Credit: Diana Juncher)

Aurora Borealis seen from the Observatory of St Andrews. (Credit: Diana Juncher)

The Aurora is not unique on Earth in the Solar System. Planets like Jupiter or Saturn, which have stronger magnetic fields than Earth exhibit even more spectacular light phenomena. Auroral light was observed on Uranus and Neptune as well.

The Northern Light we saw last Thursday was the result of a very energetic solar flare which was erupted on the 25 Feb (00:25 UTC). NASA’s Solar Dynamics Observatory (SDO) captured the gigantic flare in different wavelengths. The one seen below is a composite image of two wavelengths of extreme ultraviolet light (171 and 304 Angstroms). The flare is classified as X4.9 which means it is one of the most powerful types. As the Coronal Mass Ejection (CME) originated from this flare reached the Earth’s magnetosphere the beautiful dance of lights appeared on our sky.

Solar flare erupted on at 00:25 (UTC) 25 Feb as capured by the SDO. This image is the combination of two wavelengths of extreme ultraviolet light (171 and 304 Angstroms). (Credit: NASA/SDO)

Solar flare erupted on at 00:25 (UTC) 25 Feb as capured by the SDO. This image is the combination of two wavelengths of extreme ultraviolet light (171 and 304 Angstroms). (Credit: NASA/SDO)

And to finish with, here is a nice GIF made from some of Diana’s photos. Thanks to Inna Bozhinova for creating this short “movie” for us!

Aurora Borealis on the 27 Feb. (Credit: Diana Juncher, Inna Bozhinova)

Aurora Borealis on the 27 Feb. Click on the image to see it in a better quality. (Credit: Diana Juncher, Inna Bozhinova)

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