Quick revision to Desktop Kit instructions!
A follow-up -- the print instructions which shipped in the Desktop Spectrometry Kit ($35) contain a small error; they show the webcam being focused to 3" away, but in fact that distance should be 9". The online instructions have been revised and if you've already built your spectrometer, it's not hard to change. (download a revised PDF here) Your spectra should come out much sharper! Something like this:
Also, full instructions with build photos and lots of helpful troubleshooting tips are coming together now on the Desktop Spectrometry Kit wiki page. Check it out!
Thanks and sorry for the trouble!
--The Public Lab staff