Ground-Based Schlieren Technique Looks to the Sun and Moon https://www.nasa.gov/centers-and-facilities/armstrong/ground-based-schlieren-technique-looks-to-the-sun-and-moon/
In the wake of recent success with air-to-air schlieren photography using the speckled desert floor as a background, researchers at NASA’s Armstrong Flight Research Center, Edwards, California, are now looking to the heavens for backgrounds upon which to capture images of supersonic shock waves using ground-based cameras.
The pilots had to hand fly the airplane to hit a specific point in the sky to within