The three research centres (Paris, Meudon, Nancay) receive groups totalling about 10 000 visitors per year, consisting primarily of school-children and the general public. Tours begin with a slide-show and then visits to the instruments are guided by an astronomer. One-day courses for teachers are held at Meudon and Nancay once a month and observing evenings at Meudon. Open days are held frequently, and in May 1985, despite dreadful weather, 30 000 people visited Meudon. Each centre has prepared brochures describing its work, together with lists of postcards, slides and other material. Three slide-shows are available, and others are in preparation.