Updated

Updated · Ars Technica · Aug 7

Concorde 001 Set 74-Minute Eclipse Record in 1973 by Chasing Moon’s Shadow at Mach 2

Updated

Updated · Ars Technica · Aug 7

Concorde 001 Set 74-Minute Eclipse Record in 1973 by Chasing Moon’s Shadow at Mach 2

Q: How did a supersonic passenger jet transform into a time machine to freeze a solar eclipse for over an hour?

It worked by turning Concorde into a flying observatory that nearly matched the speed of the Moon’s shadow, so the aircraft stayed inside totality instead of letting the eclipse race past in minutes. For a ground observer, a total solar eclipse is brief because the Moon’s shadow sweeps across Earth very quickly. Even near the equator, where totality can be longest, the limit is about 7.5 minutes. In the June 30, 1973 eclipse over Africa, that shadow was still moving at more than twice the speed of sound. Pierre Léna, a French astronomer experienced in airborne observations, realized the Concorde prototype 001 was one of the few aircraft fast enough to chase it. In 1972 he asked André Turcat, Concorde’s chief test pilot and head of test flights at Aérospatiale, whether the supersonic jet could be used. Turcat agreed, and the aircraft was prepared for the mission, including a route aligned with the eclipse path. Flying at around Mach 2, Concorde effectively “stretched” time for the scientists on board. By moving with the shadow across Africa, it kept the Sun covered far longer than any fixed location on the ground could. Eight scientists aboard observed totality for 74 minutes, a world record. The jet was not literally stopping time. It was exploiting speed, altitude and precise flight planning to remain under the umbra, the darkest central part of the Moon’s shadow. That made the 1973 flight a landmark example of aviation extending the reach of astronomy.

2 articles · Updated · Ars Technica · Aug 7

Eight scientists used the Concorde F-WTSS 001 prototype on June 30, 1973 to observe a total solar eclipse for 74 minutes, a world record far beyond any ground-based viewing.
That feat was possible because the aircraft flew at more than twice the speed of sound, closely matching the Moon’s shadow as it crossed Africa near the equator.
Ground observers can see totality for only about 7.5 minutes at most, and the August 12 eclipse visible from parts of Europe will offer just over two minutes.
Pierre Léna conceived the mission in 1972 after earlier high-altitude astronomy work, and won support from Concorde test-flight chief André Turcat to repurpose the prototype.