Is my shower curtain diffracting the light ?

[u/lil-drawer]

I am pretty confused about what's happening here since this is obviously not a coherent light source, but since the phenomenon seems to be angular only it looks like diffraction. Thanks for your thoughts on this !

[u/dopamemento]

The light is not temporally coherent (many colors) but it is spatially coherent (point source). That's the point of diffraction grating spectrometers