Here is the link to the D.I.Y. Spectroscope and the Diffraction Grating from Edmund Optics.
Build your own Spectroscope with your students to explore the emission lines of various elements such as Hydrogen, Neon, Argon and more.
You can also use the spectroscopy to take photos of indirect sunlight, fluorescent lights, LED lights, flame tests and more.
The Spectroscope works best with these gas discharge tubes and the high voltage power supply.