This applet let you play with atomic spectra of hydrogen.

The wavelengths of hydrogen spectra lines can be described by the following equation:

1/λ=RH*(1/n₁²-1/n₂²)
where RH=1.0973732*10⁷ m^-1

You can change n1 with the slider bar. The program will plot a series of spectrum lines.
You might want to change the xmax(at the right) to see the full range of the spectra.
One of the line is thicker and with an arrow is the one with n2 equal to slider bar value.

Click within simulation region will toggle "visible spectra range".

You can also find out how the red shift of the spectra calculated from Hubble's law.
v=H₀ D where the recessional velocity is proportional to the distance of the star to the earth (D). You can adjust the distance of the star.
And see the red shift of the hydrogen spectra from that star due to the expansion of the universe.



n1=1 : Lyman series (Ultraviolet)
n1=2 : Balmer series (Near Ultraviolet and Visible)
n1=3 : Paschen series (Infrared)
n1=4 : Brackett series (Infrared)
n1=5 : Pund series (Infrared)