Characteristics of Astronomy-Related Organizations

Geographical distributions, ages and sizes of astronomy-relatedorganizations have been investigated from comprehensive and up-to-datesamples extracted from the master files for StarGuides/StarWorlds.Results for professional institutions, associations, planetariums, andpublic observatories are commented, as well as specific distributions forastronomy-related publishers and commercial-software producers.The highly uneven general pattern displayed by geographical distributionsis still very much the same as it was at the beginning of the XXthcentury, even if the densities are higher – another illustration of thewell-known socio-economic effect of self-reinforcement. Othergeographical peculiarities (local concentrations, national cultures andpolicies, electronic astronomy,...) are discussed in the paper, aswell as the uneasy separation between amateur and professional astronomersin associations.Some events had a clear impact on the rate of foundation ofastronomy-related organizations, such as World Wars I and II, thebeginning of space exploration, the landing of man on the Moon, the end ofthe Cold War, spectacular comets, and so on. However, as detailed in thepaper, not all of them affected in the same way Western Europe and NorthAmerica, nor the various types of organizations.The size of the vast majority of astronomy-related organizations isrelatively small, with again some differences between Western Europe andNorth America.