Now You See It, Now You Don’t
As darkness deepens Thursday, you’ll find the first-quarter moon high in the south-southwest with the bright star Spica seven degrees to its lower right.
Friday night the moon has pulled eastward and is equidistant from Spica to its right and Saturn to its left. Even closer to the left of the moon is the faint star Zubenelgenubi, which marks the fulcrum of the celestial scales Libra. Train binoculars on this star, however, and you’ll see that it is actually a double.
Saturday the waxing gibbous moon is just a few degrees above and to the right of golden Saturn with the red star Antares, whose name translates to Rival of Mars, a little beyond the ringed planet. Sunday the moon, Saturn and Antares form a tight triangle, with Saturn a few degrees to the right of the moon and Antares about the same distance below the moon.
Venus and Jupiter are the only other planets visible this week. They appear low in the west at twilight and are still within 10 degrees of one another this week. Regulus, the eye of Taurus the bull, is a little higher than the two planets, but they all creep a little lower each night.
The near-full moon will limit the display from the Delta Aquarids meteor shower, which peaks in the wee hours between Tuesday and Wednesday, July 28 and 29. But with a little luck, you might still catch a few brighter meteors streaking across the sky. Best viewing is after midnight. The meteors can appear anywhere in the sky, but tracing their path backward they all appear to radiate from the constellation Aquarius.
If you’re up before dawn Wednesday or Thursday, you might catch a fleeting glimpse of the International Space Station, which shines brighter than any star and moves as fast as a jet. Wednesday it is visible for six minutes, popping into view at 4:55am, 40 degrees above the northwest horizon and blinking out of sight just as quickly at 5:01am, 10 degrees above the east-southeast horizon. Thursday it appears 24 degrees above the north-northwest horizon at 4:02am and disappears five minutes later, 11 degrees above the east horizon. Learn more at http://spotthestation.nasa.gov/sightings.