H-alpha is an important line used in astronomy to detect the presence of hydrogen.

The Balmer series is particularly useful in astronomy because the Balmer lines appear in numerous stellar objects due to the abundance of hydrogen in the universe, and therefore are commonly seen and relatively strong compared to lines from other elements.

Hydrogen-alpha, typically shortened to H-alpha or Hα, is a deep-red visible spectral line of the hydrogen atom with a wavelength of 656.28 nm in air and 656.46 nm in vacuum. It is the first spectral line in the Balmer series and is emitted when an electron falls from a hydrogen atom's third- to second-lowest energy level.

Hydrogen can absorb and emit in the ultraviolet region of the spectrum (the Lyman series) but the emissions and absorptions we see in the visible part of the spectrum are the Balmer series and occur when electrons jump from and fall to the n=2 orbit. Why Alpha?

H-alpha lines are usually the ones you see when observing most nebulae. If you search why is that, why are H-alpha lines more visible than H-beta, H-gamma or H-delta, the usual answer is that H-alpha is "stronger".

In 1885, J. J. Balmer, a lecturer in a ladies' college in Switzerland, devised a simple formula relating the wavelengths of the lines in the visible region of the atomic hydrogen spectrum to the natural numbers, and these lines have since been referred to as the Balmer series and have been denoted by H\(\alpha\), H\(\beta\), H\(\gamma ...

H 2 is the symbol for the molecular hydrogen molecule which is abundant in giant clouds in our galaxy and can be detected by its infrared spectrum. The symbols HI and HII are used to indicate neutral and ionized hydrogen respectively.

DUMAND (Deep Underwater Muon and Neutrino Detector.) Welcome to the Fact Guru Astronomy knowledge base. The left pane shows Astronomy subjects arranged in a concept hierarchy - each subject is a kind of the subject above it.

In the absence of emission lines from ionized gas, the (optical) spectrum of a galaxy will be the sum of the spectra of individual stars. These spectra will have absorption lines for hydrogen (H-alpha, H-beta, H-gamma, H-delta, etc.); the absorption lines are strongest for A stars and weaker for both earlier (O, B) and later (F, G, K, M) stars.

One of the most commonly used spectral features in astronomy are the spectral lines of Hydrogen, called the Balmer lines. The lines are named, from longest to shortest wavelength: The Hydrogen Alpha, Beta, Gamma, Delta, and Epsilon lines (or in simplified notation – …