Robert,
Practical Astronomical Spectroscopy by Tonkin has a whole chapter on CD/DVD gratings by David Randell.
Over on the Astronomical Spectroscope Yahoo forum
http://tech.groups.yahoo.com/group/a...guid=322612425
One of the members "Jack" is VERY supportive of CD/DVD gratings!!
I found them next to useless for anything other than showing what a spectrum looks like! HOWEVER, I would like to try the "spare" blank and clear disks that come in those stacks of CD's. I think there MAY be potential to use one as a transmission grating. Don't know anyone who has actually trialed it yet - want to be the first???