Sodium light source, 20W low pressure discharge lamps for spectral work. Delivers approximately 350 lux at 20 cm and more than 90% of the light is concentrated in the doublet at 588.9/589.5 nm. Faint lines of the mercury spectrum are also visible.
Mercury light source, 20W low pressure discharge lamps for spectral work. Delivers approximately 100 lux at 20 cm with prominent lines at 434.7, 546.0, 577.0, and 579.1 nm as well as many faint lines.