The Star Cluster files, assembled over her 40 years as an astronomer, represent the core of Dr. Hogg's research in a field for which she is an authority and from which many of her published articles were derived. The files are variously comprised of raw data, calculations, correspondence, draft and published articles relating to specific globular clusters. Prints from photographic plates also accompany some files . Most files are titled according to the New General Catalogue number, e.g. NGC 6626, of the star cluster and are arranged numerically following Dr. Hogg's own filing system.
A set of ten boxes of bibliographic index cards accompanies the Star Cluster Files. Cards in boxes seem to relate to specific subjects ie. external galaxies, variables in clusters, interstellar absorption. Boxes /044 - /048 are arranged more or less chronologically by the date of the bibliographic references. All were used for various editions of "A Catalogue of Variable Stars in Globular Clusters". Box B1994-0002/048 appears to relate specifically to references used in "A of Bibliography of Individual Globular Clusters" and its supplement. Index cards in box B1994-0002/049 do not appear to be bibliographic references but rather relate information on specific star clusters and are arranged by NGC number.
Photographs have been left in their original files because of their immediate association with the research materials. It was feared that removal of these photos from individual files would obscure the meaning of both the research in the file and the photographs themselves.