Most of us consider weekends a time for sleeping in, but skywatchers who get up before the Sun are presently in for a treat. A trio of planets will dance with the bright star Antares, and on the mornings of the 17th and 18th there will be a guest appearance by the waning crescent Moon. The performance is free, but clear skies and an unobstructed southeastern horizon are required. Bring your opera glasses or small binoculars for a better view.
Mercury, Mars, and Jupiter made headlines last weekend when they were so tightly aligned in the dawn sky that they could be hidden behind the thumb of an outstretched hand. They're farther apart now, and Mercury is lower, making it more challenging to spot, but Antares has joined the troupe of celestial players. This is a fine time to see for yourself why the star's conspicuous red tint has earned it the appellation "The Rival of Mars."
As the accompanying diagram shows, the crescent Moon enters the scene in the dawn of the 17th and it forms its tightest grouping with the planets the following morning. As you gaze at this celestial scene you are looking across space and time. Light from the Moon has been on its way to us for about 1.3 seconds, Mercury 11½ minutes, Mars 20 minutes, Juipter 52 minutes, and Antares since before Columbus discovered America.