Duck on a pound VS Cherenkov radiaton cone

[tresgog]

Here are two pages showing examples of the Cherenkov radiation:
http://physics.syr.edu/hep/rich.html
http://www.iss.infn.it/webg3/cebaf/hadron.html

I don't understant why the cone is ahead of the particule path.

I thought that the cone of light formed behing the particule path (like the v shaped shoc wave behind a duck)

Can somebody clear this up for me?

[Vanadium 50]

The cone shows where the light ends up, not where it is produced.