Historical person
Historical biography and chronological timeline for Helen Sawyer, based on 1 World History Database records associated with United States of America.
Harlow Shapley and Helen Sawyer began categorizing clusters according to the degree of concentration the system has toward the core. The most concentrated clusters were identified as Class I, with successively diminishing concentrations ranging to Class XII. This became known as the Shapley-Sawyer Concentration Class
This biography is assembled from World History Database records filtered by country and personal-name fields. Exact duplicate display records are removed. The database is an index rather than a complete narrative biography; formal research should verify entries against relevant primary or specialist sources.