|IC 1795, a star forming region in Cassiopeia|
APOD ©2011 Bob and Janice Fera (Fera Photography)
(Ionization is the process of converting an atom or molecule into an ion by adding or removing charged particles such as electrons or ions. An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. wikipedia)
|Hydrogen alpha emission|
In the simplified Rutherford Bohr model of the hydrogen atom, the Balmer lines result from an electron jump between the second energy level closest to the nucleus, and those levels more distant. The transition depicted here produces an H-alpha photon, and the first line of the Balmer series. For hydrogen (Z = 1) this transition results in a photon of wavelength 656 nm (red).
Update: APOD 7 June 2012 has an impressive image of Venus transit taken with narrowband H-alpha filter. The red light from hydrogen emission shows interesting details on the surface of Sun not visible in regular photos.
|Metrope's Reflection nebula in Pleiades|
APOD ©2012 Leonardo Orazi