Evening planets Mars appears to be a modest red star, low above the southwestern horizon, just as the sky darkens. Only observers with a very low southwestern horizon will be able to spot the red planet. Mars will track slightly eastward but will appear to stay about the same altitude all month. Just as the sun sets tonight, bright Jupiter will rise in the east. You can’t mistake this giant world for a star. It’s much brighter. If the clouds part, December will be a very good month to study the multicolored cloud bands and the ever-changing Galilean moons. This …