Scientists modify Concorde 001 and fly with the Moon's shadow across Africa, remaining in totality for 74 minutes instead of the roughly seven available from the ground.
The eclipse was moving. Concorde was faster than most objections.
A total solar eclipse has an inconvenient feature for astronomers.
It moves.
On Saturday, 30 June 1973, the Moon's shadow crossed Africa during an exceptionally long total eclipse. An observer standing in the right place could experience a little over seven minutes of totality.
Scientists wanted more.
Their solution was Concorde 001.
The prototype supersonic aircraft was modified for astronomical observations, including special windows for instruments. It took off from Las Palmas in the Canary Islands and went looking for the Moon's shadow.
Over North Africa, Concorde intercepted the path of totality.
Instead of allowing the shadow to sweep over the aircraft and disappear, the pilots turned along its path and flew with it across the continent.
Concorde travelled at approximately Mach 2.05. The Moon's shadow was moving in the same direction.
For the seven observers aboard, the result was extraordinary.
They remained in totality for 74 minutes.
The aircraft had not altered the eclipse. It had altered the observers' relationship to it, remaining inside the moving shadow far longer than any stationary observer could.
Researchers from France, Britain and the United States used the extended darkness for experiments involving the solar corona, chromosphere and atmosphere. Flying above much of the atmosphere also reduced weather risk, absorption and sky noise.
The mission eventually landed at Fort-Lamy, today's N'Djamena in Chad.
Most eclipse expeditions involve travelling somewhere and waiting for the Moon.
This one reversed the arrangement.
The Moon's shadow arrived.
Concorde followed it.
Scientists wanted more time inside a solar eclipse, so they placed their instruments aboard a supersonic prototype and flew with the Moon's shadow across Africa at roughly twice the speed of sound.
The eclipse lasted the usual amount of time. The observers simply refused to let it leave.
Evidence status
Sources
Original scientific report
Original language: EnglishAstronomy institute record
Instituto de Astrofísica de Canarias — Eclipse Flight of Concorde 001
Original language: Spanish / English