This week skywatchers get a chance to track down some of the brightest stars and planets of the season, thanks to the wanderings of Earth’s lunar neighbor.
Moon and Spica. After nightfall on Monday, July 15, gaze towards the low southwest for the first quarter moon extremely close to the bright star Spica. The pair will be less then one degree apart—equal to the width of your thumb at arm’s length.
Mars and Star Cluster. About a half hour before local dawn on Tuesday, July 16, orange-hued Mars will park itself beside Messier 35, an open star cluster. The Red Planet will appear to be less than half a degree—about the width of the disk of the moon—from the center of the group of stars.
Lying near the foot of the Gemini twins, M 35 is 2,800 light-years away from Earth and is best seen with binoculars and telescopes. The loose cluster of hundreds of young stars stretches nearly 30 light-years across, and takes up about the same area of sky as the full moon. (Learn more about Messier 35.)
Moon Slides to Saturn. Starting at dusk on Tuesday, look towards the low southwest for a waxing gibbous moon hanging underneath the ringed planet. The cosmic duo will appear only three degrees apart. Saturn is the second largest planet in the solar system after Jupiter, and is about 95 times the mass of the Earth. (Related: “Eye-Catching Triple Planet Huddle.”)
Moon visits Anti-Mars. Look towards the low southwest on Thursday, July 18 near midnight for the bright orange star Antares to the lower left of the waxing moon. The red giant, 600 light-years away from Earth, will appear six degrees from our moon—a little more than the width of your fist at arm’s length.
Antares is the brightest member of the constellation Scorpius and marks the mythical arachnid’s ‘heart’. Considered one of the reddest of the brighter stars of the night sky, Antares’ name means anti-Mars’—Ares being the Greek word for Mars, the god of war. For northern observers, the constellation always hugs the southern horizon, and for southern hemisphere skywatchers, Scorpius dominates the overhead night sky. (Learn more about Antares.)
Earth-Saturn Portrait. On Friday, July 19, between 5:27 and 5:42 p.m. EDT look up and smile! The Cassini spacecraft orbiting Saturn will turn its cameras towards the sun so it can capture a unique family portrait of the Earth alongside Saturn and its majestic rings.
This will be the first time in history Earthlings know in advance that their picture is being taken from a billion miles away. Find out more information on the event’s official site.
Mars meets Jupiter. Before local dawn on Sunday, June 21 the red planet will have dropped below M35 star cluster and pay an extremely close visit to the largest world in the solar system. Orange-hued Mars will appear less than one degree from Jupiter low in the east. The two planets will glide past each other in the Gemini constellation over the course of the next few days as Jupiter rises higher each morning while Mars sinks close to the sun. For the best views, observers will need to have a clear line of sight towards the horizon using binoculars.
Venus pairs with Regulus. As dusk sets in on Sunday, July 21, look towards the very low western horizon for a beautiful pairing of two bright white, star-like objects. Regulus, the brightest star in the constellation Leo, will set fast while brighter Venus snuggles up to it—only one degree away.
The best views will be with binoculars from southern latitudes, where the pair will appear higher in the sky and farther away from the sunset glow.