The database initially contained only astronomical references, but has now grown to incorporate three databases, covering astronomy (including planetary sciences and solar physics) references, physics (including instrumentation and geosciences) references, as well as preprints of scientific papers from arXiv.
Database awalnya hanya berisi referensi astronomi, tetapi sekarang telah berkembang untuk menggabungkan tiga database, meliputi astronomi (termasuk ilmu-ilmu planet dan fisika surya) referensi, fisika (termasuk instrumentasi dan geosains) referensi, serta pracetak karya ilmiah dari arXiv.