Can I tag along?
let's not take over this thread but sure, get a jump on the project by making your "DIY spectrograph" -see: Google

I'll link to the software that does the webcam magic as soon as I can finish it up

but basically I'm mounting a webcam to the viewport on my spectragraph tube measuring light intensity, per pixel, in area's of the image that the webcam grabs, it may require some calibration between different webcams, i only have one, but I'll be sure to come here to find testers