THE BLACK SUN – A RARE ...

"There are things which one has known for fifty years, yet only in the fifty-first year is one’s amazement at the grandeur and fearfulness of it all aroused. This is how I felt during the total solar eclipse which we experienced, under the most favourable skies, in the early hours of the morning on 8th July 1842 in Vienna….I knew everything about a total solar eclipse so well beforehand that I believed I could describe it accurately in advance as if I had already seen one.

But when it finally became reality, as I stood and watched with my own eyes from a vantage point high above the city, other quite different things happened; things which I had never thought of, neither awake nor asleep; things which nobody thinks of who has not seen such a wonder.

Never and never in my entire life was I so shaken by awe and sublimity as in those 2 minutes. It was as if God had spoken a clear word to me and I had understood. I descended from my vantage point, like Moses may have descended from the burning mountain thousands and thousands of years ago, with a perplexed and numbed heart."

Adalbert Stifter (1805-1868), translation of parts of the original German text "Die Sonnenfinsternis am 8. Juli 1842" (The solar eclipse of 8th July 1842) (Complete German text)

For a less prosaic overview of the phenomena occurring during a total solar eclipse, we recommend the tutorial written by of EarthView.


... AND WONDERFUL SPECTACLE OF NATURE

During Adalbert Stifter’s lifetime, a total solar eclipse, the sight of the "black sun" was generally a once-in-a-lifetime experience. Thanks to the various sophisticated forms of travel in this day and age, we no longer have to wait until the black sun once again passes over Central Europe in 2081, we can go and see it at any distant corner of the earth. Statistically, a total solar eclipse occurs at the same place only once every 360 years. However, with the world at one’s doorstep, a wait of no more than 18 months on average is necessary for the next chance to see the black sun. Solar eclipses in general occur even more frequently. Every year, at least 2, sometimes 3 or 4 (as will be the case in 2011) or, on rare occasions, up to 5 eclipses occur. The 21st century will see an average of 2.24 eclipses per year.

Only about one in three eclipses, however, is a total eclipse, meaning that the moon’s course crosses exactly the path between the earth and the sun so that the solar disc is completely obscured – or in other words, the Moon’s umbra (shadow) is cast on the earth. In another third of cases the moon is slightly "off target" and only covers part of the sun, resulting in a partial eclipse (the earth only passes through the moon’s penumbra). The two eclipses which will occur in 2007 will be of this type. It is also possible that, although the moon’s orbit passes exactly between the sun and the earth, the sun is still not completely covered as the moon at this time is a greater distance from the earth and therefore has a smaller apparent diameter than the sun. Around the sun a gleaming "ring of fire" remains visible, known as an annular (or ring) eclipse. The moon’s umbra does not reach the surface of the earth during this kind of eclipse, which likewise constitutes the remaining third of the different types. Like total eclipses, annular eclipses can also only be seen from a very small section of the earth (the next one in Central Europe not being until 2075). Outside the narrow central zone, total and annular eclipses appear as partial eclipses across an area of about 7,000 km (4,350 miles) in width. This means, for example, that it was possible to observe the annular eclipse of 03.10.2005 all over Germany as well as in many other parts of Europe. The ring of fire, however, did only appear in a wisp of sky above the Iberian Peninsula.

If you would like to find out more about the mechanics of the sky, take a look at the homepage of the South African Astronomical Observatory. These additional links are also recommended:

A Catalogue of Eclipse Cycles by Robert Harry van Gent
Saros, Inex and Eclipse cycles by Felix Verbelen
Eclipse Statistics by hermit.org
General eclipse information (in German) by ETH Zürich

WHEN AND WHERE CAN THE BLACK SUN BE SEEN?

Total Eclipses of the Sun up to 2015
[Tables containing all solar eclipses between 2001 and 2030 can be found on Fred Espenak's Eclipse Home Page.
Short descriptions of all total solar eclipses up to 2020 are given by Robert A. Braeunig]

Date	Type	Magnitude	Duration	Visibility	Details
01.08.2008	Total	104 %	02m27s	Canada, Europe, Asia [Total: N-Canada, Greenland, Siberia, Mongolia, China]	INFORMATION TRAVEL PAGE
22.07.2009	Total	108 %	06m39s	E-Asia, Pacific, Hawaii [Total: India, Nepal, China, C-Pacific]	Coming late 2007
11.07.2010	Total	106 %	05m20s	southern S-America, Pacific [Total: S-Pacific, Easter Island, Chile, Argentine]	Coming late 2008
13.11.2012	Total	105 %	04m02s	Australia, New Zealand, Pacific, Antarctic [Total: N-Australia, S-Pacific]	Coming 2010
03.11.2013	Annular/ Total	102 %	01m40s	Brazil, Africa, S-Europe [Annular/Total: Atlantic, C-Africa]	Coming 2011
20.03.2015	Total	104 %	02m47s	N-Atlantic, Europe, N-Africa, N-Asia [Total: N-Atlantic, Faroe Islands, Svalbard]	Coming 2012

Eclipse Predictions and graphics by Fred Espenak, NASA/Goddard Space Flight Center
For more information on solar and lunar eclipses, see Fred Espenak's Eclipse Home Page:
sunearth.gsfc.nasa.gov/eclipse/eclipse.html

Compared with total eclipses, partial ones are not so spectacular. Only when the sun is hidden to a significant degree (90% and more) does the daylight become noticeably dimmer. For this reason, such events are barely perceived by much of the population despite their incidence in Europe every few years. More awe-inspiring are annular eclipses, particularly when the sun rises or sets as a ring of fire. An annular eclipse otherwise has nothing or little of the special features of a total eclipse, with the exception of the "pearl necklace effect" (also called "Baily´s Beads"). Especially annular eclipses where the sun is almost completely hidden (over 99 %) afford a very impressive display of this kind, but even if the sun is covered to a lesser degree, this phenomenon can also be seen at the edge of the circular eclipse zone.

PLANNING YOUR JOURNEY: WHERE IS THE BEST OBSERVATION SITE?

The zone in which a total eclipse is visible, although limited in width, is very long as can be seen in the illustration of the solar eclipse on 22.07.2009. The first consideration, therefore, when making travel plans is one’s destination. The following criteria should be taken into account when determining the ideal observation point:

1) The duration of the total eclipse should be as long as possible, and the sun high in the sky.
2) The statistical probability for clear skies should be high.
3) The political situation of the region must not pose an obstacle to travelling to the place in question.
4) A well-developed infrastructure (roads, transport facilities) is important to be able to reach the destination without any difficulty, or, if necessary, to be able to move at short notice to a new location on the day of the eclipse should clouds set in.

If on a voyage at sea (pleasure cruise), points 3 and 4 are, of course, irrelevant.

ASTRONOMICAL EQUIPMENT: WHAT IS TO BEAR IN MIND?

A lunar eclipse, a shining comet, a Mercury transit, but also a partial or annular solar eclipse – these are all exciting celestial happenings which are observed, be it with the naked eye, with binoculars or with photographic equipment. A total solar eclipse, in comparison, is an elementary natural phenomenon that promises to be a much profounder sensory experience. Only two pieces of equipment are necessary – eclipse glasses or a simple, hand-made pinhole camera for watching the partial phases of the eclipse without risk, and a white sheet or piece of cloth for capturing the "flying shadows" which can occur shortly before and after the totality. Then you are ready to surrender all 5 senses to the impending spectacle. Perhaps then you will feel something similar to that described so expressively by Adalbert Stifter.

Nevertheless, there are still many reasons for choosing to watch a total solar eclipse with telescopes or for recording photographically the diverse optical phenomena (photographers should refer to the informative tables compiled by NASA with regard to Exposure time and the influence of the focal length on the size of the sun’s image). For an ambitious observation programme the amount of material required soon adds up, and then there is still the matter of transporting it all to your chosen observation point - usually having to rely on an aeroplane to get you there. In this regard, the information below should be taken into account:

1. The loss of expensive astronomical equipment is usually not covered by normal luggage insurance. Nowadays, however, special telescope insurance is offered by hobby astronomers working in the insurance business.

2. If you are taking extensive apparatus with you, the luggage allowance specified by the airline (usually 20 kg/45 lbs) may easily be exceeded, which might cost a small fortune in excess baggage. There are a number of different options for getting around these costs. If, for example, only a short holiday of a few days is planned, the remaining luggage can be reduced to a minimum to keep under the 20 kg limit. If your luggage is only slightly heavier than permitted, you can hope that the airline might turn a blind eye, yet this is not to be relied upon. It may be more advisable to maximise your hand-luggage (i.e. that what you take on the plane with you). However, since the security measures at most airports have been heightened considerably, size and weight of hand luggage is often subject to stringent controls.

3. If planning to camp on your holiday – this type of accommodation will be popular for the eclipse on 29.03.2006 - it should be clarified no later than at the time of booking exactly how much equipment, if any, can be taken along. Generally, there shouldn’t be a problem as such tour operators accommodate other nature enthusiasts who are often accompanied by cameras and spotting scopes.

In order to avoid any unpleasant surprises, we would kindly ask you to inform us at the time of your booking request whether you would like to take with you extensive astronomical equipment and roughly how much this will weigh (in kg).