I figured that science types probably had some fancy name for it, full of numbers and whatnot, similar to how we catalog stars or planets. I can't imagine people would have been too interested in it, most of the astronomy stories that get much attention are either asteroid-impact scares or talk of alien life. It does hinge on where Calamity is located though. David mentioned that it's always in the same spot in the sky, which implies geosynchronous orbit. If something was orbiting the Earth like that, and it wasn't some top-secret government thing, then the public would likely care and probably would have come up with a name for it.