Although I have witnessed several partial solar eclipses, in all my years of astronomy, I have never had the good fortune to be in the right place at the right time to experience the unparalleled cosmic spectacle that is a total solar eclipse. I was therefore determined that this year would be the one where all this changed and so I travelled from the UK with my wife and son to Madrid a couple of days before the eclipse was due.
There we were hosted by our Spanish friends, Alex and Lola Alonso who had prepared a viewing site a kilometre or so from Lola’s family’s country house at Cedillo de la Torre, in Segovia province, about 100 km North of the capital. Coincidentally, the village was right on the track of totality and normally has only 78 permanent residents. That day however that number increased several-fold.
The main highway running North from Madrid was already jam-packed with traffic when we set off mid-morning to get to Cedillo. For days beforehand, overhead signs on the motorway had been warning about not stopping to view it on the highway and giving basic viewing precautions. It seemed half of Spain was on the move.
Alex and Lola had chosen the specific site we would use very well - separate from where most of the crowds were likely to be in the village and with a clear, relatively flat horizon. We had to drive about a kilometre or so on a dirt road from their house to reach it, but that was all.
The day was typically clear and hot for August in this part of Spain, with just some haze on the horizon. That concerned us beforehand just a little as this eclipse was due to reach totality less than an hour before sunset, with the Sun therefore relatively low in the sky. We need not have worried however as it did not detract at all from what was to come.
The Alonso’s wider family and friends began to gather around 7pm CEST, 20-30 people in all. Alex asked me to give a short introduction to what we would be seeing from ‘first contact’ around 7.30pm, through totality roughly an hour later, until the Sun finally set some time around 9pm. A couple of tennis balls and some Euro coins came in handy as props at this point!
The most serious points of the briefing revolved around never looking at the uneclipsed Sun with the naked eye or any form of optical instrument without special glasses or filters. It was ensured beforehand that there were enough eclipse glasses etc to go around. Alex had also prepared a ‘pin hole theatre’ using a shoe box and aluminium foil to view a projected image of the Sun as the eclipse progressed.
The evening before the eclipse, we’d had dinner with colleagues from Thailand and Germany and their partners – Saran Pochyachinda of NARIT and Michael Kramer of Bonn, both of whom are highly involved in projects in Botswana and have given talks to the ASB on several occasions. Saran is a dedicated ‘eclipse chaser’ and this would be his 15th total solar eclipse! He gave some really good advice about what to do in the minute and a half of totality we were about to witness: ‘this is the only time you can view safely without the special glasses, and if you feel confident, you should do this’, and ‘just take in the moment and don’t let recording it for example distract you from the experience’. All this was sound advice that I passed on to the group.
Over the next hour, the moon was seen to take an increasingly large ‘bite’ out of the solar disc and even before totality the temperature noticeably dropped and the quality of the light changed. Finally, only a sliver of the sun was left, then just a very bright spot (some call this the ‘diamond ring’ phase) and it then seemed a very rapid transition to totality. Everyone gasped and spontaneously applauded and hugged as day turned to night, the birds stopped singing. On command we took off our eclipse glasses to see the Sun as I had never seen it before.
The very hot outer atmosphere of the sun, the corona, stretched out around it, tracing the solar magnetic field. One other feature clearly stood out – a small but bright red arc stretching out from the black of the Moon’s disc. This was a solar prominence where hot gas is being ejected from the solar surface and streaming back again. The red colour is due to a prominent emission line of hydrogen in the stream. It was a truly awe-inspiring spectacle in every way. Among other things, it gave a real impression of the 3-dimensional universe in which we live. We agreed however that for ancient peoples to whom all this would happen unexpectedly, this must have been incredibly terrifying.
Less than two minutes later, it was protective glasses back on and the light and heat returned as the Sun was gradually uncovered again as it set towards the distant horizon. Even this was a spectacle in itself as the partial phase continued through sunset, silhouetting a distant wind farm.
An incredible and unforgettable experience and we are obviously very grateful to Alex and Lola for hosting us. In all the excitement, Alex still managed to take the photos shown here, although I completely forgot to set my phone on record just to capture people’s reactions as I’d intended.
That will have to wait for next time – now we are hooked too. The next total solar eclipse is August 2nd next year and again Spain will be a good place to view it, but this time on the extreme South coast. Then on July 22nd 2028 it will be Australia’s turn, but on November 25th 2030, Southern Africa, including Botswana, will be treated to this unparalleled cosmic spectacle. We hope to be at all three events!
Mike Bode is Visiting Professor of Astrophysics at BIUST and Deputy Chair of the ASB
For those interested in the technical details of the photography undertaken by Alex:
Camera – Sony RX10 M4, operated fully manually
Filters – At the beginning and end of the eclipse, combined filters ND1000 and ND64, then only the ND1000, and finally no filter at all during totality]