“…In the gravitational version of this problem, the system is characterized by two parameters: the mass parameter, which is the ratio of the central mass to a peripheral one (β = m 0 /m) and the number ν of the peripheral primaries. We emphasize the advantage of the regular polygon (or otherwise ring) model which, with the change of its parameters, is reduced to some problems of Celestial Dynamics that appeared in the past in international literature, such as the Copenhagen case of the restricted three-body problem (ν = 2 and β = 0), the restricted four-body problem of Marañhao (1995) (ν = 2, β = 0) and the restricted five-body problem (Ollöngren 1988;Markellos et al 2002) (ν = 3 and β = 0), while two of the basic configurations studied by Roy and Steves (1998) in their Caledonian problem, can also be obtained when ν = 4 and β = 0, or ν = 3 and β = 1. Here, we study the simple periodic orbits of a particle, which moves under the combined gravitational action of 8 much larger bodies (ν = 8) with equal masses that are located at the vertices of a regular octagon, while another body with different mass lies at the center of mass of the system (Fig.…”