In our library we define observatory publications as all materials disseminated in serial form and on its own behalf, by an observatory, astronomical institute or university department. Included are annual reports, research reports, reprints, newsletters, and monograph series. Preprints, though fitting the description, are handled separately. Excluded and catalogued separately are individual monographs and users manuals. Sometimes items such as catalogues and atlases are catalogued and shelved elsewhere with a dummy left in the appropriate place.

Traditionally, libraries have shelved observatory publications alphabetically according to the city or town in which the observatory is located. Reference tools such as Astronomy and Astrophysics Abstracts and the Bibliography of Non-commercial Publications have used that arrangement too. One of the problems of this system is that without a number, it does not provide a single, unique, identifier for observatories with many locations. The same holds true in cases where there are many observatories in one location. In addition, the location may not be known or the library’s arrangement may have idiosyncracies.