Why do some people try to chase eclipses in a jet plane?
The only reason that total solar eclipses only last a few minutes for a ground-based observer is that that is about how much time it takes the lunar shadow, traveling at over 2,000 km/hr to pass you’re your geographic location. But what would happen if you could fly along the path of totality at the same speed as the lunar shadow? Well, you would see a continuous eclipse for as long as the shadow touches Earth, which can be several hours from start to finish. Astronomers figured this out long ago, but had to wait for the invention and deployment of non-military supersonic jets to carry out such a chase. The scientific benefit is enormous because now you can study the sun’s corona for much longer than the 2-5 minutes usually allowed. On June 30, 1973, Concorde 001 intercepted the path of a solar eclipse over North Africa. Flying at Mach 2.05 the aircraft provided seven observers from France, Britain and the United States with 74 min of totality bounded by extended second (7 min) and third (12 min) contacts. The former permitted searches for time variations of much longer period than previously possible and the latter provided an opportunity for chromospheric observations of improved height resolution. The altitude, which varied between 16,200 and 17,700 m, freed the observations from the usual weather problems, and greatly reduced atmospheric absorption and sky noise in regions of the infrared.