2 The data

At the time of writing, there were 6080 entries in the master files, out of which about a thousand were simple cross-pointers. Thus the total number of effective organizations gathered together was 5086 with a total of 1504 sets of coordinates available.

It is interesting to notice that, in spite of the fact that sets of coordinates have been explicitly requested on our questionnaires sent for many years to all the organizations approached, less than a third of them registered at least one position. There are of course plenty of good explanations for that effect: institutions carrying out only theoretical research, associations badly located or without enough financial resources to afford observational means, and so on. Also the basic activities of a substantial number of organizations included in the resource are totally extraneous to observing. This is particularly the case for publishers, retailers, manufacturers, software producers, and so on. What is sure though is that providing coordinates in that context is a positive sign of a deliberate observational policy from the corresponding organizations.

It seemed appropriate to sort out the entries in three categories for this study: institutions, public observatories and planetariums, and finally associations. The first one is clearly related to professional astronomers. The two latter ones deal mainly with amateur astronomers and the grand public. They have strongly similar educational missions. The two last categories could of course be merged for a statistical investigation such as the current one, but it should be kept in mind that public observatories and planetariums have a more official structure and a better stability (mainly because of the buildings, equipment, and personnel involved) than most associations, the nature of which is consequently different.

Out of a total of 1857 institutions registered at the time of writing, we retained 610 of them who provided coordinates of observing sites. As quite a few of them had several observing sites, the total number of coordinates sets retained for that group was 816. Not all institutions with coordinates were selected: from the registered profile of activities, we did not take for instance those exclusively involved in aeronomy, but we did include those studying the solar-terrestrial relationships, and so on. Some borderlines had to be adopted and we did it by making the best usage of the information provided by the organizations themselves (as part of the authentication/verification process, we request a report of activities).

There were 739 entries registered as public observatories and planetariums (not unfrequently both of them together) in the master files, out of which 269 (36%) provided coordinates. The total number of locations for this category went up to 295 by including secondary sites. This is above average which can be understood since public observatories are, by definition, places where observations are logically conducted. In this category, 299 entries were purely public observatories and 183 of them (61%) provided coordinates.

Out of the 1327 entries registered as associations in the master files, only 306 (23%) of them provided coordinates of observing sites, well below the overall average. With the secondary sites, a total of 355 locations was reached. An obvious conclusion from these figures is that many associations have no observing sites or at least no fixed observing site, but of course members might have their own private facilities, not necessarily considered as being under the responsibility of the association. Some associations are also managing public observatories and planetariums, or they are using their sites, so there might be some overlap, but this is true for only a small number of them and it does not affect the statistical results (the corresponding locations are anyway superimposed on the maps).