The NASA Astrophysics Data System at Harvard

The Digital Library for Physics, Astrophysics, and Instrumentation. The Astrophysics Data System (ADS) is a NASA-funded project which maintains four bibliographic databases containing more than 4.4 million records: Astronomy and Astrophysics, Instrumentation, Physics and Geophysics, and preprints in Astronomy. The main body of data in the ADS consists of bibliographic records, which are searchable through our Abstract Service query forms, and full-text scans of much of the astronomical literature which can be browsed though our Browse interface. Integrated in its databases, the ADS provides access and pointers to a wealth of external resources, including electronic articles, data catalogs and archives. We currently have links to over 4.5 million records maintained by our collaborators. Their use is free for personal use only