Acroynms of Astronomy (Wikipedia) http://en.wikipedia.org/wiki/List_of_astronomy_acronyms en:List of astronomy acronyms http://en.wikipedia.org/wiki/List_of_astronomy_acronyms Acroynms of Astronomy (Wikipedia) https://en.wikipedia.org/wiki/List_of_astronomy_acronyms#N List of astronomy acronyms en:List of astronomy acronyms http://en.wikipedia.org/wiki/List_of_astronomy_acronyms Acroynms of Astronomy (Wikipedia) hydrogen-alpha en:List of astronomy acronyms