CLEMSON, South Carolina – Clemson University scientist Donald Liebenberg has personally witnessed and researched 26 total solar eclipses over the past 60-plus years.

Liebenberg, who has been an adjunct professor in the College of Science’s department of physics and astronomy since 1996, has literally travelled all over the world to enter the path of totality of solar eclipses. He has studied them from the ground, on ships in the middle of oceans, and in airplanes. He even watched one eclipse from the cabin of a Concorde supersonic airliner — chronicled below — where he was able to remain within the window of totality for an astounding 74 minutes.

The Concorde eclipse on June 30, 1973 above Africa was his ninth eclipse. His 26th eclipse was March 9, 2016 aboard the cruise ship MS Vollendam off the coast of Indonesia.

All told, Liebenberg has spent more than two and a half hours in totality, which surpasses anyone else on Earth.

The upcoming Aug. 21, 2017 event over Clemson will mark Liebenberg’s 27th eclipse. He has also witnessed several other eclipses that were nearly – but not quite – in the path of totality.

Today is the eighth chronicle of all 26 of Liebenberg’s eclipse adventures on our Eclipse Over Clemson blog. Most segments will focus on one eclipse. But during a few of the installments, Liebenberg will describe more than one eclipse, so that we will have time to visit them all before the arrival of Aug. 21.

However, the Concorde eclipse was too grand for just one segment, so it has been broken into two parts. Part 1 is chronicled below. Part 2 will appear next week.

Please sit back and continue to enjoy this amazing adventure.

This map shows all 26 total solar eclipses that Donald Liebenberg has witnessed in person.

This map shows all 26 total solar eclipses that Donald Liebenberg has witnessed in person. Image courtesy of


Eclipse No. 9: June 30, 1973        Totality: 74 minutes

Where: Over Africa          Weather conditions: beautifully clear, dark skies

The 1973 eclipse across much of Africa was close enough to the Earth’s equator to provide a long totality, which is exactly what we needed to advance our ongoing research.

Dr. Donald Liebenberg

Dr. Donald Liebenberg

A few years earlier, the discovery of oscillation waves on the solar surface had broken new ground. The first and strongest wave on the photosphere had a period of about five minutes, although more oscillations of various periods were also reported. My thought was to investigate whether this oscillation on the solar surface would propagate into the corona, where we might detect it. Meanwhile, the Concorde supersonic commercial aircraft had already undergone several test flights, and with modifications was being built – but had not yet been approved – for commercial service.

The NC-135 aircraft commissioned to the Los Alamos National Laboratory would provide an eclipse duration of about 12 minutes of totality, but even this wasn’t long enough to significantly enhance our research.

But the Concorde, which could fly mush faster and much higher than any other aircraft of its kind, was a different story. I began to imagine just how much more we could learn if we married our research efforts with this new and astounding supersonic jet.

Dr. Art Cox and I wrote a letter in late summer of 1972 to Dr. Pierre Charvin at the Paris Observatory suggesting the use of the Concorde for eclipse observations, since both takeoff and landing sites were available across Africa. We heard nothing back until early January 1973, but then I was invited to go to Paris and Toulouse to discuss my proposal in more detail. I was hopeful, but the negotiations were really just beginning.

I went to the assistant director of LANL and asked about flying on the Concorde. I was told that the craft was experimental and therefore not covered by LANL’s insurance. I knew the insurance officer and went to him. He said there would be no problem; he could add a rider to the lab’s policy via Lloyd’s of London.

I suggested he make the insurance for two. Then I flew to Paris and was met at the airport by representatives of the Aerospatiale Group in charge of the Concorde project. They took me to a hotel for an hour or two of rest and then to offices where I would be interviewed by Charvin and several managers. The aircraft personnel said that the Concorde 001 could be made available but that its engines had been modified and no replacements were available. I told them that I was prepared to chance it. This opportunity was worth taking risks.

The Concorde 001 supersonic jet was one of the technological marvels of its time. Photo courtesy of Donald Liebenberg

The Concorde 001 supersonic jet was one of the technological marvels of its time. Photo courtesy of Donald Liebenberg

I was then asked to travel to Toulouse to discuss the engineering of the project in more detail. I left for the airport, checked in and was in the waiting area for the flight when I noticed people beginning to leave. My French is very limited, but I was finally able to discern that the pilots at the airport had gone on strike and that all flights had been cancelled.

To say the least, this was quite inconvenient. But there was nothing I could do about it, so I collected my checked bag and got directions to the train station. Luckily, there was an overnight train to Toulouse. On the platform, I showed my ticket for a berth to the conductor, and he told me to wait. He never returned. I heard the whistle blow for departure. But I would not be denied. I got on board, determined that we would settle any problems while on the way to Toulouse.

The conductor finally found me and took me to the upper of three berths in a sleeper car. As it turned out, all was well and we arrived in time for breakfast in the train station at Toulouse. I had not had much to eat, and the French onion soup I was served was – to this day – the best I’ve ever had. (As a side note, my wife and I visited Toulouse not long after, and she agreed with my assessment of the onion soup.)

I arranged transport to the Aerospatiale plant and was taken to a conference room, where I was provided with an interpreter. We discussed my initial sketches, and they pointed out the power and weight limitations we would need to include in our designs. At noon, we went to the company dining room for lunch. In the afternoon, I was informed that my French was good enough that I didn’t need a translator. Was this when the tricky questions would be asked, in order to take advantage of me? My suspicions proved fruitless. The engineers were happy to work with me, and a number of them spoke some English, because the Concorde was a joint British-French program.

I had packed my ski boots, and during an off day I arranged transportation to a ski area about 100 miles away. The trails were poorly marked and it was scarily foggy, but I still managed to get in a couple of good runs. Not everything about being a scientist is hard work. We get to fit a little pleasure – sometimes in exotic locales – into our otherwise vigorous schedules.

Donald Liebenberg (left) and Bob Lang are shown on the Concorde 001 with the equipment in place. Photo courtesy of Donald Liebenberg

Donald Liebenberg (left) and Bob Lang are shown on the Concorde 001 with the equipment in place. Photo courtesy of Donald Liebenberg

However, the next three months were very busy for me, and I could not have succeeded without considerable help from various divisions and groups within LANL. I wrote a proposal to the National Science Foundation for travel support and to pay the Aerospatiale Group my share of the Concorde 001 flight costs. This amounted to more than $250,000, which was a considerable sum in 1973. The LANL could not pay these costs – in particular the foreign travel costs – so I had an account set up at LANL via NSF that provided travel funds for myself and others.

The equipment was due at Aerospatiale in Toulouse in late April. Time was running short.

Bob Lang and Ed Brown of LANL constructed our equipment into a single standalone package, with the tracking mirror located at a pre-built window that was cut into the Concorde. Additional filters for pre-dispersion were purchased. A second pressure scanning FPI system was constructed, and we obtained a six-inch diameter objective lens and additional lenses for focusing the coronal light.

Ralph Partridge set up the photoelectric sensors for image stabilization, and I worked on the interferometer. Marvin Hoffman and Mort Sanders provided another image intensifier video camera, tape recorder and the associated electronics that were integrated into the system.

In the end, we met the date for delivery to Aerospatiale in Toulouse. Lang and I went over to assemble the equipment and test it outside in the sun.

During a holiday weekend in France, I wanted to continue to work on the equipment, so I asked about coming in on the holiday. The management agreed, but I required a 400-cycle power source. Undeterred, the staff took me to another building and showed me how to switch on this power for use on our equipment. On the holiday, I walked into the plant and passed the manned guard gate. After that, I saw no one else. I turned on the 400-cycle power and did my work. I thought about this in connection with whether Boeing or Lockheed in the U.S. would have let a foreigner come in alone, switch on power in another building and work on his equipment without any supervision. Aerospatiale deserved a big thank you. When it comes to scientific achievement – especially when it crosses borders – trust can be a powerful tool.

This 1973 illustration shows the eclipse flight path of the Concorde 001. Photo courtesy of Donald Liebenberg

This 1973 illustration shows the eclipse flight path of the Concorde 001. Photo courtesy of Donald Liebenberg

Things were now progressing well. But we still had a long way to go before we could fly in totality aboard one of the most amazing aircraft the world had ever known.

To be continued …

Up next: Eclipse 9 / Part 2 of Concorde flight