1. The problem statement, all variables and given/known data My final year project at university is to visualise the test section of a supersonic wind tunnel by schlieren method, though I'm having a bit of trouble setting it up. The light source I am using is a halogen bulb, in an old lamp housing, with a condenser on the end with a focal length of 300mm According to sources I have been using, a pin hole should be used to make it a point source the distance of the focal length away The light rays will then be reflected off a spherical mirror, the focal length of the mirror away (930mm) through the test section and onto a spherical mirror on the other side. 2. Relevant equations 3. The attempt at a solution I've struggled to get the whole thing going, I put the light source, pin hole and mirror the appropriate distances away, but the light image I'm getting on the other side of the pin hole is rubbish. Any thoughts? Thanks in advance.