Mir16609@aol.com asks - >Does anyone have a rough idea about the visibility (brightness) of the >Chandra when it is in it's final orbit? not very. Chandra's roughly the same size as Hubble and similar insulation blankets. So it's probably got the same intrinsic magnitude. But the final orbit is *far* above Hubble's low altitude orbit so it's going to be much fainter. I suppose you could try to look at it through a telescope while it's at perigee, but I can't see any other reasonable way to track it visually. Philip Chien, KC4YER Earth News world (in)famous writer, science fiction fan, ham radio operator, all-around nice guy, etc.