We have active collaborations with the Observatoire de la Côte d’Azur (Nice, France) (P.Michel, P. Tanga), the Dept. of Astronomy of the University of Maryland (USA) (D.C.Richardson), the South-west Research Institute (Boulde, CO, USA) (D.D. Durda; W.F.Bottke), the Dept.de Física (Univ. de la República, Uruguay), the Instituto de Astrofísicade Andalucía (Tenerife, Spain), (J. Licandro; J. de León), the Insituto de Astrofísica de Andalucía (Granada, Spain), the Institut d’ Estudis Espacials de Catalunya (CSIC)(Barcelona, Spain) (J.-M. Trigo).