Total solar eclipse in the Arctic, visible as a partial eclipse in Germany
March 18, 2015
Total solar eclipse in the Arctic, visible as a partial eclipse in Germany
On Friday morning the Moon will cross the Sun’s disk
For observers in Germany, a rare celestial spectacle will occur on Friday morning – a partial solar eclipse, in which the Moon crosses the solar disk, covering up to 80 percent (depending on location) of our star. The Sun will only be completely covered in the Arctic Ocean. However, the effects on the general ambience of the environment may be noticeable in Germany as well under ideal conditions – some darkness, for example.
As in this image of the chromosphere from NASA’s Solar Dynamic Observatory, the surface of the Sun with several prominences and sunspots, taken in extreme ultraviolet light, the phenomenon should only be observed using special filters.
Please note that you should never look directly at the Sun without special solar eclipse protective glasses, to prevent damage to your eyesight.
The path of the solar eclipse across the North Atlantic
The total eclipse of the Sun on 20 March 2015 will only be visible above the North Atlantic and the Arctic Ocean. Thousands of amateur astronomers and curious individuals will be hoping that the weather does not thwart their plans. The path of totality, or the core shadow (umbra) of the Moon (grey stripe), on the northern hemisphere shows that the solar eclipse can only be observed from a few places on dry land – the Faroe Islands, for example, or Spitsbergen. The central line indicates the trail of maximum duration, along which the coverage of the Sun will last the longest. The Sun will be close to the horizon, as 20 March marks the date of the start of astronomical spring and the end of the polar night.
The solar eclipse begins at 10:11 at longitude 45 degrees west, to the south of Greenland. The cone of the Moon's shadow then rapidly races towards the northeast. The eclipse can be observed for the longest period of time at 10:44 CET, around 300 kilometres south-southeast of Iceland; it will reach Spitsbergen at 11:09 CET and end shortly afterwards at the North Pole.
This Friday, 20 March, will see the rare event of a solar eclipse. The Sun will not be completely covered in Germany and central Europe; the total solar eclipse will only be visible in the Arctic Ocean. Nevertheless, in this part of the world, between 60 and almost 80 percent of the solar disk will be covered in the late morning (depending on the observation location) – a partial solar eclipse.
Important! Never look directly at the Sun without eye protection especially designed for solar observation. These are available from many opticians as well as for purchase on the Internet. Astronomical observatories near you, at which the solar eclipse can very probably be observed with expert guidance, weather permitting, will also have this special protective eyewear. Never look directly at the Sun with binoculars or telescopes either – you run the risk of blinding yourself! You even risk damaging your eyes if you wear high protection sunglasses.
The Moon's passage across the solar disk will be very long – over two hours
This solar eclipse in the northern hemisphere will last an unusually long time because the Sun is still not very high in the sky in March. From around 09:30 CET (in Munich; 09:39 in Berlin), the Moon will visibly start to cross the Sun's disk from the west at 'first contact'. The maximum obscuration in Germany will be reached at 10:39 (10:47). In Munich this will be 67.7 percent, in Berlin 74.2 percent and in Hamburg a full 79.2 percent. Assuming the sky is cloud-free, it will be easy to see the Moon appear as a semi-circular shadow crossing between Earth and the disk of the Sun, giving it the appearance of a ‘crescent’ Sun.
Hence, this solar eclipse is similar to the last one visible in Germany on 4 January 2011, although this time, on 20 March – coincidentally the date of the Vernal Equinox (the start of astronomical spring) – the Sun will be significantly higher in the sky. And even though the sky will only darken partially in central Europe because there is only a partial eclipse at our latitudes, the effects of the slight darkening will be noticeable. In ideal circumstances, an effect on the general ambience of the environment may be noticeable at around 10:45 – pale light, for example, and very small openings will cast small crescents on the ground instead of circular images of the Sun.
Equinox eclipse in the Arctic Ocean expected to be very spectacular
Clearly more impressive is observing the total eclipse, when the disk of the Moon lies precisely in front of the solar disk and the observer is located in the zone of the core shadow (umbra) of the Moon. This is the only time that the corona (crown in Latin) of the Sun can be seen from Earth. The corona is the outermost part of the solar atmosphere, with turbulent gas eruptions of fully ionised plasma heated to several million degrees Celsius. Because of the scattering effect of Earth’s atmosphere, this phenomenon cannot be seen from the planet's surface, simply because the Sun is dimmed down to a circular disk. Such observations were of especially great mythical significance to our ancestors.
This total eclipse of the Sun is also of interest as it takes place exactly on the date of the start of astronomical spring and within the Arctic Circle. This means that the thousands of 'eclipse tourists' who will follow the event on ships off Iceland and on the Faroe Islands or Spitzbergen will see the Sun very close to the horizon.
The images of a solar corona directly above Earth's horizon in the numerous available live streams and in photographs taken from these observation sites are expected to be decidedly spectacular and, above all, unique, as they would not have been technically possible before. However, the photographers will have to be quick – totality only lasts around two minutes. The Moon's shadow will race across the northern hemisphere at several hundred kilometres per hour. The longest eclipse will be observed at latitude 64.28 degrees north and longitude 6.9 degrees west, which is about 300 kilometres south-southeast off the east coast of Iceland.
The next total solar eclipse in Germany will happen in 2081
Solar eclipses are very rare events. The last total eclipse of the Sun in central Europe passed over southern Germany on 11 August 1999. The next eclipse with a similar coverage of the Sun to this one will take place in 2026, and the next total eclipse of the Sun in central Europe will not occur until 3 September 2081!
Two, or in fact, three astronomical parameters must be met for a total solar eclipse to take place. First, the Moon must be new. The second condition that must be met is that the new moon is located at one of the two nodes in its path around our planet, which is slightly inclined to the plane of Earth’s passage around the Sun (the ecliptic). The term nodes describes when the path of the Moon around Earth, which is at an angle of around five degrees to the ecliptic, passes through the ecliptic at two points – the nodes. At these times, the centres of the Sun, Moon and Earth are exactly or almost exactly in a straight line. This is why solar eclipses do not happen every time there is a new moon. The highly conical shadow of the Moon can only reach Earth’s surface when the new moon occurs at one of the two nodes.
Finally, the small Moon with a diameter of 3476 kilometres must appear bigger than the Sun, with its diameter of 1.4 million kilometres. If the Moon is at its furthest point from Earth – at a distance of 406,000 kilometres – it is an annular eclipse; but between the average distance of the Moon from Earth of 383,000 kilometres and its minimum distance of 363,000 kilometres is perfect for an eclipse.
Astronomical coincidence – Sun and Moon have the same apparent diameter
The fact that the small Moon can cover the large Sun is simply an astronomical coincidence. Its diameter is 400 times smaller than that of the Sun, but the Sun is also 400 times further away from the Earth than the Moon (150 million kilometres from the Earth-Moon system). In the distant future, our descendants will no longer be able to observe the spectacle of a corona. This is because the Moon is receding from Earth at about 3.8 centimetres per year. Therefore, it is merely an extraordinarily lucky astronomical circumstance that the Moon has been orbiting Earth for several thousand generations of human history at precisely the distance that permits 'ideal' coverage of the disk of the Sun.
