Hess diagram

{{Short description|Diagram of stars in astronomy}}

{{confuse|Hasse diagram}}

Image:Hess diagram.jpg b>80 degree]]

A Hess diagram plots the relative density of occurrence of stars at differing color–magnitude positions of the Hertzsprung–Russell diagram for a given galaxy or resolved stellar population. The diagram is named after R. Hess who originated it in 1924.{{cite book| author = R. Hess (Heß) | date = 1924 | page = 265 | chapter = Die Verteilungsfunktion der absoluten Helligkeiten in ihrer Abhängigkeit vom Spektrum | title = Probleme der Astronomie. Festschrift fur Hugo v. Seeliger | publisher = Springer, Berlin}} Its use dates back to at least 1948.{{cite journal

| author=Gaposchkin, Cecilia Payne

| title=The connection of motion with intrinsic variability.

| journal=Astronomical Journal

| date=1948

| volume=53

| pages=193

| bibcode=1948AJ.....53..193G

| doi=10.1086/106093

| doi-access=free

}}

Hess diagrams are widely used in the study of discrete resolved stellar systems in and around the Milky Way - specifically, in the analysis of globular clusters, satellite galaxies, and stellar streams.