Buuxi weedhan soo socota: 1920 dood ayaa dhexmartay Harlow Shapley iyo Heber Curtis
Doodda Weyn), oo ku saabsan dabeecadda Wadada Caanaha, nebulae-yada isbeddelka ah, iyo cabirka caalamka. Si uu u taageero sheegashadiisa ah in Nebula weyn ee Andromeda uu yahay galaxy dibadeed, Curtis wuxuu xusay muuqaalka wadooyinka mugdiga ah ee u eg daruuraha boodhka ee Wadada Caanaha, iyo sidoo kale wareejinta Doppler ee muhiimka ah.