"William Hamblen" wrote in message
rthlink.net...

The blue ray would be refracted differently from the red ray and the
spot where the blue ray exits the second face of the glass plate would
be displaced a little from the spot where the red ray exits. This causes
some false color to appear around your star image.

Hey!, even _I_ understood that (I think). :-)

Good one Bill (if I can call you Bill).

-Stephen Paul