Download or read book The ∆a photometric system written by Ernst Paunzen and published by Cuvillier Verlag. This book was released on 2020-10-13 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the characteristics and applications of the Δa photometric system, which measures the stellar flux at around 520 nm. Since its introduction in 1976 by Hans-Michael Maitzen, the Δa system has not only been successfully applied to the classical chemically peculiar stars of the upper main sequence, but also to galactic and extragalactic star clusters. New possible applications for studying galaxies, quasars and other astrophysical objects of interest are discussed.