Re: IL Lup = 4U1543-47 bright outburst! IL Lup = 4U1543-47 has an orbital period of 1.123 d and has the secondary type A2V (Orosz et al. ApJ 499, 375). These parameters are similar to those of the microquasar V4641 Sgr. It would be interesting to see how does IL Lup behave during the present activity state. Regards, Taichi Kato