Schlieren photography
![A schlieren photograph showing the compression in front of an unswept wing at Mach 1.2](/Images/godic/202502/09/Schlierenfoto_Mach_1-2_gerader_Flügel_-_NASA3813.jpg")
![Shock waves produced by a T-38 Talon during flight using analog background-oriented schlieren from the Sun's edge](/Images/godic/202502/09/Schlieren_photograph_of_T-38_shock_waves3813.jpg")
![Schlieren image of a shotshell projectile exiting a barrel.](/Images/godic/202502/09/-Schlieren_Video_Of_Shotshell_Transitional_Intermediate_Ballistics_-_Nathan_Boor_of_Aimed_Research.ogv3813.jpg")
![Colour schlieren image of the thermal plume from a burning candle, disturbed by a breeze from the right.](/Images/godic/202502/09/Schlieren-color-candle-plume3813.jpg")
Schlieren photography is a visual process that is used to photograph the flow of fluids of varying density. Invented by the German physicist August Toepler in 1864 to study supersonic motion, it is widely used in aeronautical engineering to photograph the flow of air around objects.