V520 Persei
V520 Persei is a blue supergiant member of NGC 869 , one of the Perseus Double Cluster open clusters . 
<triplet> V520 Persei <subj> NGC 869 <obj> part of <subj> Perseus <obj> constellation <triplet> NGC 869 <subj> Perseus <obj> constellation <subj> Double Cluster <obj> part of <subj> open cluster <obj> instance of <triplet> Double Cluster <subj> NGC 869 <obj> has part <subj> Perseus <obj> constellation <subj> open cluster <obj> instance of