Watching a total eclipse means different things to different people. Some want to perform scientific experiments, some want to capture its spectacular beauty on film, and others simply want to witness first-hand the sheer excitement and beauty of this most extraordinary piece of natural theatre.

There is much more to the solar eclipse experience than just the moon passing in front of the sun. It defies description, and films or photographs can only hint at the reality of the vision. For those who have never experienced a total solar eclipse the memory of your first minutes within the moon shadow will last a lifetime....

I’d heard about eclipses, I even knew some of the jargon, but nothing prepared me for my first one. About an hour before 'totality' I could sense the growing excitement; the moon had bitten into the sun and was inching its way across. During that hour, the colour slowly trickled out of the landscape. It was eerie, and too slow and subtle to properly grasp. With minutes to go my heart was racing, but I still didn’t know what for. I could feel that something was going to happen: something big, and that there was no stopping it. The horizon to the south-east was suddenly very dark, the shadow of the moon was bearing down upon us. The remaining colour dropped out of the scenery. I thought my heart would stop as the sky literally disappeared in front of my eyes. The sliver of remaining sunlight evaporated and the sun was gone. It was cold. Stars and planets were clearly visible. And there, hanging in the sky was the vast black rock we call the moon, a titanic sphere, framed with dusty clouds of light streaming out from the hidden sun. I was looking into space. The next three and a half minutes were overwhelming. I gazed in open-mouthed awe. Then the light came back: just a tiny part of the sun’s surface, visible through a valley on the edge of the moon. It was the brightest, most intensely powerful light, and it burst out like a laser and cut its way through the scene, sweeping the darkness away. Dazzled, I looked away, then the world as we know it rolled back into place, as if to say "I had you worried..."

26th Feb 1998 - Curacao, Dutch Caribbean

The Stages of an Eclipse

First Contact:
The moment when the first small bite appears in the edge of the sun.

Second Contact:
The moment when the sun is completely covered.

Totality:
The period of time (usually a few minutes) following second contact when the sun can be observed with the naked eye.

Third contact:
The moment when the sun reappears from behind the Moon.

Fourth contact:
The moment when the sun is completely restored.

Photosphere:
The bright solar surface that we normally see and which is completely covered during the total eclipse.

It sometimes surprises people that the eclipse can be quite advanced before it becomes noticeable that something is happening to the quality of the light. The fall in light level is very gradual at first but seems to accelerate particularly in the last ten minutes before totality. The greatest drop in light intensity is in the last four seconds and is very dramatic.

As the eclipse progresses the colour of the sky seems to change, and the intensity of brightly coloured objects seem to soften. If there are trees or bushes around, the little gaps between the leaves act as pin-hole cameras to throw many overlapping images of the crescent sun on the ground. This becomes more noticeable as the crescent sun narrows.

Just before the eclipse becomes total you may see the shadow of totality advancing like a wall across the landscape rapidly towards you. Except in special circumstances, the shadow of totality moves from west to east. The visibility of the shadow will depend on the clarity of the atmosphere and your location, whether you are on a mountain overlooking a plain for example. Also, the speed of the shadow varies. In the early morning or late evening the shadow may be travelling at a speed of perhaps 12,000 miles per hour, whereas if you are observing the eclipse near noon on the equator the shadow may be travelling at 1,500 mph.

Baily’s Beads are a familiar feature of total eclipses. As the moon completely covers the sun, the razor-thin solar crescent breaks up into a chain of beads which gradually wink out. When the last one disappears, totality has started.

Just as the eclipse becomes total, at the point where the last Baily’s Bead has disappeared for a second or two you will see a bright red streak along the limb of the Moon. This is an upper layer in the solar atmosphere called the chromosphere. It is quite bright though not as bright as the photosphere.

The most noticeable feature during totality is the solar corona, the outer atmosphere of the sun that is only visible to the naked eye during a total eclipse. It consists of pearly-white streamers radiating outwards.

Prominences are flamelike appendages to the chromosphere which may be seen at any location round the eclipsed sun, perhaps being larger and more spectacular at times when the sun is very active. It is also interesting to note that as the moon moves across the sun during totality, prominences in the area where second contact took place start to be covered up, whereas others in the vicinity of where third contact is about to occur become larger as the moon uncovers them.

Among the most dramatic features of an eclipse are the colours during totality. The disc of the moon is completely black, surrounded by the pearly-white of the corona with occasional flame red prominences. The sky is a deep purple-blue and around the horizon the sky is usually an orange colour reminiscent of sunset. This strange mixture of colours can make everyday objects look positively surreal.

A glow around the horizon is due to sunlight outside the shadow of totality being reflected inwards. The actual colour can vary from reddish-orange to yellow.

During totality the sky is not as dark as nightime, so only the brightest stars may be seen; however, It is worth having just a quick glance around the sky to see which stars and planets are visible. There is always the possibility that totality will reveal a comet close to the sun which had not been observed before due to its proximity to the sun.

The chromosphere starts to emerge from behind the rim of the moon at the location where the photosphere will reappear at third contact. This occurs just a second or two before third contact and gives a good warning that the sun is about to reappear. If you are using optical equipment to observe totality this warns you to now look away before the light of the photosphere reappears.

The Diamond Ring is one of the most dramatic features of the whole eclipse. As the first point of the photosphere reappears we see something that resembles a giant diamond ring in the sky with the small portion of the photosphere being the diamond and the rapidly fading corona being the rest of the ring. It is in fact the same configuration as the last Baily’s bead at second contact but the difference lies in the adaptation of our eye. At second contact our eyes are used to the bright light and can perceive the last bead as a small point. However our eyes become dark-adapted during totality and so the reappearance of the sun can be dazzling.

Experiments
As you might expect there are many experiments that scientists can perform under the unique circumstances of a total solar eclipse. However here are three experiments which can be performed with little or no specialised equipment if you feel you wish to do more than just simply look. For a beginner, even just taking a photograph with a simple camera will record something and will be a personal souvenir of the event.

If there are animals or birds around it might be worth noting their behaviour as the partial phase increases and what actually happens at the moment of totality. Eclipses are so unusual that they give wildlife observers the opportunity to study the adaptability of species to these very special circumstances.

One experiment that is very simple to perform using the stopwatch facility available on many watches is to simply time the duration of totality, i.e. from the moment the last Baily’s Bead has disappeared to the Diamond ring effect. Timings are useful and should be passed on to professional astronomers.

There are so many special features associated with Total Solar Eclipses and each eclipse, due to weather and other factors, is unique; you really have to observe several to enjoy the many phenomena presented to you. But be warned, total solar eclipses are addictive!

Eye Safety
The sun radiates visible light but its photosphere also emits intense infrared and ultra violet radiation. Just as this radiation causes sunburn it will also cause damage to your eyes which need only be exposed to direct sunlight for a few seconds to sustain permanent damage.

The only way to view the uneclipsed or partially eclipsed sun is through a special filter. Explorers Tours will provide a solar filter for each person for safely viewing the partial phases of the eclipse.

During totality the moon completely masks the photosphere making it completely safe to look at the sun with the naked eye, through your telescope or with binoculars.