NGC 3603 was observed by John Herschel on the 14th of March 1834 during his visit to South Africa, who remarked that it was "a very remarkable object...perhaps a globular cluster".
Foi observado por John Herschel o 14 de marzo de 1834 durante a súa viaxe a Suráfrica, quen remarcou que "é un obxecto notable ... posiblemente un cúmulo globular".