NASA Astrophysical Data System - ADS

NASA Astrophysics Data System (ADS) (external link) is a virtual library portal for researchers in the fields of Astronomy and Physics, which is maintained at the Harvard-Smithsonian Astrophysical Observatory (SAO) on behalf of NASA.

Altogether there are three bibliographical databases updated weekly with over 7.7 million entries (as of 2008):

  • One database for Astronomy and Astrophysics
  • One for Physics
  • A mirror version of the database of ArXiv e-prints


The Astronomy literature has been scanned in, in many cases going back to the first edition of the journals in question, and is available in full-text versions. The Physics literature goes back for varying periods depending on the collaborative partnerships (for example, with CrossRef since 2008).


Using ADS services is free of charge; however access to the full texts depends on whether the search location has a licence for the publications in question (where applicable).


Courses are held by appointment. They cover the following aspects:

  • Literature searches in the fields of Astronomy and/or Physics
  • Exporting references to various literature management programs
  • Customising ADS Services


You can learn the basic principles from the following resources: