Optical Spectrometer

http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/diffracon.html#c1

http://physics.nist.gov/asd
http://www.du.edu/~jcalvert/phys/dischg.htm
http://www.frontiernet.net/~jlkeefer/balmer.html
http://www.jordan.dpsnc.net/Science/Physics/Hphysics2002_2003/wavesLab02-03