Lyman beta (Ly-β or Lyβ)
is a hydrogenspectral line,
the second line in the Lyman series, following Lyman alpha (Ly-α).
Like Ly-α, it is of interest for astronomical observation.
It has a wavelength of 102.6 nm, in the extreme ultraviolet (EUV) range
(as is the whole Lyman series) and cannot be observed from
the ground unless considerably redshifted.
It is generally less strong then Ly-α,
but is strong enough to be used in some of the same ways,
e.g., detect clouds at such long distances by
noting the absorption lines in the EMR of quasars
at the wavelengths indicating Ly-β various redshifts,
and can form a Lyman-beta forest.
In addition to confirming some conclusions drawn from analogous
Ly-α observations, it has value in that it can be
observed from the ground at somewhat smaller redshifts than Ly-α,
adding to the data that can be collected by ground telescopes.