EntityQ7581353· pop 5· linked from 26 articlesSproul ObservatorySign in to saveobservatory in Pennsylvania, United States (1913–2017)Connectionsplanetary systemEntitySwarthmoreEntityUnited StatesCountryastronomyEntityPennsylvaniaEntitygeographic coordinate systemEntityPittsburghEntitytelescopeEntitydigital object identifierEntityobservatoryEntityastrometryEntitybibcodeEntityBarnard's StarEntityrefracting telescopeEntityBentonvilleEntitymeasurement errorEntityMagdalenaEntityphotographic plateEntityPeter van de KampEntitySwarthmore CollegeEntityCategories2017 disestablishments in PennsylvaniaAstronomical observatories in PennsylvaniaPlanetary systemsSwarthmore College