Eclipse

On July 2, 2019 the so-called Great South American Eclipse took place. The total eclipse path ran over parts of Chile and Argentina, where the Moon was seen to move in front of the Sun and blocked the sunlight out completely.

Figure 1. SWAP eclipse image sequence from the first passage of the 2017 August 21 eclipse.

UPDATE: The SWAP images are received from the satellite. Check out the pictures and movies below. 

Monday, 21 August 2017 has marked an important celestial event, a total solar eclipse. This was a well observed event, as the eclipse transited the whole of North America. The path of the eclipse can be seen here. People along the path saw a total eclipse, and those outside this path witnessed a partial solar eclipse where the moon covers part of the sun's disk. The eclipse was visible for about two and a half minutes from any location along the path of totality, and first seen on the west coast of the USA in Oregon at around 10:19 am PDT and finally in South Carolina at around 02:44 p.m EDT (more timing information can be found here). For more information on other types of eclipses, visit here.

On 2016 March 8 and 9, a solar eclipse took place over the Pacific Ocean. This eclipse was total -that is, the entire solar disk was covered by the Moon- over Indonesia and the central Pacific, starting at sunrise over Sumatra and ending at sunset north of the Hawaiian Islands. Additionally, large parts of South-East Asia, Alaska and Australia witnessed a partial solar eclipse. The path of totality had a maximum width of 155 km and the maximum duration was 4 minutes and 9 seconds at the point of greatest eclipse, which was over the waters of the Pacific Ocean.

The total solar eclipse observed in March 2015 caught a lot of people's attention, especially as the path of totality passed over most of Northern Europe. There was a great deal of fan-fair and plans to observe the eclipse from the ground. However, due to heavy cloud cover, a lot of people had to turn to space-based observations, such as those made by the sun watching extreme-ultraviolet imager: SWAP, on board the European Space Agency's PROBA2 satellite, which images the Sun from the vantage point of a polar Earth orbit, away from pesky cloud cover. More information about the March eclipse can be found here and here.

SWAP observes the solar corona in a passband centered on a wavelength of 17.4 nm. The structures seen in SWAP images have a temperature of approximately 1 million degrees. More information about the SWAP instrument is available here.

It may come as some surprise, especially for those in Europe, that there was another eclipse observed on 2015-Sep-13. Whether you are able to observe an eclipse from the ground depends on your geographic location, in contrast to the March eclipse which was seen from Northern Europe and the Arctic regions, the September eclipse was observed in the southern hemisphere from Antarctica and southern Africa. In any given year the Earth will experience at least 2 solar eclipses due to the Earth and Moon's orbit.

To read about the PROBA2 eclipse observation campaign and see images of the eclipse, follow this link.

When ESA posted the video of SWAP’s observations of the March 20 solar eclipse on YouTube a number of viewers shared comments and questions about several unexpected aspects of what they saw. A few viewers were so surprised by what they saw that they even wondered if the images were really authentic. The images were most assuredly real, but nonetheless we on the PROBA2 team were likewise intrigued by similarly unexpected things that we saw in the observations.

Some of the questions commenters asked have straightforward — if not exactly simple — answers, while others required us to dig deeper and do some real research of our own to try to address them.

Among the questions raised in the comments were:

• Why does the Moon move across the Sun from east to west, the opposite direction of motion from what viewers on the ground observed?
• Why didn’t the Sun appear to rotate in the movies as it does in many movies from PROBA2 and other Sun-observing spacecraft?
• Why did the Sun change so little during the movies? Shouldn’t there have been some dynamics visible in the corona?
• Why did the movie play so quickly? Why were there so few frames showing the eclipse?

Let’s have a look at these questions to see what we can learn about the Sun, solar eclipses, and the PROBA2 spacecraft from them.

Updated (25 March 2015): On 2015 March 20, PROBA2 observed a total solar eclipse — twice! The spacecraft's orbit carried it through the darkest parts of the Moon's shadow two times, first between 08:28 and 08:53 UT and again between 10:24 and 10:50 UT. Eclipse chasers, scientists, media and members of the general public have been following our data closely, so we are collecting all of our results and data products in one place for quick access.

SWAP, an Extreme-Ultraviolet solar telescope, observes the solar corona in a passband centered on 17.4 nm. The structures we see in SWAP images have a temperature of approximately 1 million degrees. LYRA, an X-ray/Ultraviolet radiometer observes the total incoming light levels from the Sun in several wavelength bands.

More information about these instruments is available here: SWAP | LYRA.

Nederlands English

Le 2 novembre 2009, une fusée Rockot décollait de Russie, emportant dans ses flancs le satellite PROBA2, qu'elle plaçait sur orbite quelques heures plus tard. Au cours des cinq années qui ont suivi, PROBA2, dont la mission scientifique est gérée par des membres de l'Observatoire Royal de Belgique à Bruxelles, a effectué plus de 25000 orbites — plus d'un milliard de kilomètres — autour de la Terre, acquis plus d'un million d'images du Soleil, et été le témoin de plus de 6000 éruptions solaires.

Français English

Op 2 november 2009, bracht een Russische Rockot raket de PROBA2-satelliet in een baan om de Aarde. De wetenschappelijke missie van PROBA2 wordt geleid door wetenschappers van de Koninklijke Sterrenwacht van België in Brussel. In de vijf jaren sedert de lancering draaide PROBA2 al meer dan 25000 rondjes om de Aarde — meer dan een miljard kilometer —, maakte de satelliet meer dan een miljoen beelden van de Zon, en werden meer dan 6000 zonnevlammen waargenomen.