Many astronomers are currently watching the constellation Corona Borealis (CrB) for the long-awaited outburst of the repeating variable star T CrB. When that happens (possibly in the next few weeks), "T Cor Bor" is expected to brighten dramatically, a couple thousand times in a matter of hours. Look just above Arcturus and slightly to the left. If the sky is dark, you'll see a set of stars shaped like a cup without a handle. That's the constellation Corona Borealis, the Northern Crown. Only one of its seven stars is very bright, and it's called Alphekka, which is...