H-alpha

As H -alpha or Hα in astronomy and physics, the brightest spectral line of excited hydrogen ( chemical symbol: H) is referred to in visible light. It is located in the red light at a wavelength of 656.28 nanometers and is of particular importance for solar observation. Special interference filters ( Fabry -Perot interferometer ) allow sunlight to pass only in this area, so that the exact structure of the uppermost sun layer ( chromosphere ) with the solar flares and filaments is visible.

Since hydrogen is the most abundant chemical element by far in space, observations of H- alpha filter not only stars, but also for gaseous nebulae and other celestial objects are revealing.

The Hα line is the brightest of a series of lines, which is named after its discoverer Balmer series ( Jakob Balmer, 1885). The other of these lines are called Hβ, hv etc., where Hβ is the greenish-blue light, hv in the blue-violet and Hδ at the violet edge of the visible spectrum. Other lines ( Hε, Hζ, ...) are already covered in the UV range and were not discovered until later. The wavelength of this radiation are emitted when an electron from a higher to the second deepest [note 1] energy level of its orbit around the atomic nucleus " jumps down ". Conversely, they are absorbed (i.e., in dark lines ), when an electron from the incident light takes the energy which it needs to transition to a higher energy level.