The moon is now back in the predawn sky, moving past the planets Jupiter and Mars there. On Sunday morning – September 29, 2013 – you’ll see the waning crescent moon and brilliant planet Jupiter easily because they are the two brightest objects up before the sun. From the Northern Hemisphere, look generally toward your southern sky. From the Southern Hemisphere, look in the northern sky. If you wake up at least an hour before sunrise, you’ll see another planet, Mars, as well. And you’ll see the two brightest stars in the constellation Gemini the Twins – called Castor and Pollux – near Jupiter now on the sky’s dome.
For the next several mornings, before dawn, you can watch as the moon moves between the two morning planets, Jupiter and Mars. The moon is moving in an eastward direction – away from Jupiter and toward Mars, on the sky’s dome. The moon paired up with Jupiter on the morning of September 28 before dawn. It will appear close to Mars in the coming days.
If you’re up before dawn, you should easily see the Gemini twin stars, Castor and Pollux, in the vicinity of Jupiter. Although Castor and Pollux are bright stars, they pale next Jupiter. Still, you’ll enjoy picking them out. Castor and Pollux are noticeable on the sky’s dome for being bright and close together. The two stars are similar in brightness, though Pollux is actually the brighter of the two. They make an elongated triangle with Jupiter now before dawn, as seen from around the world.
In our western mythology, Castor and Pollux depict the heads of mythological twins, the sons of Zeus and Leda. These two stars have been labeled as twins throughout history and in many cultures. The Arabs referred to them as the “two peacocks” and the Hindus as the “twin deities.” If you see them in the sky, you’ll know why; they really are noticeably bright and close together on the sky’s dome.
These twin stars – Castor and Pollux – more or less mark the radiant point of the famous Geminid meteor shower, one of the finest showers of the year. This shower happens each year in December. Read more about the year’s meteor showers here.
Look above for a more detailed chart of the eastern, predawn sky on Sunday, September 29. The bright star Regulus sits fairly low in the eastern sky in the dark hour before dawn, too. By drawing an imaginary line from Jupiter through the star Regulus, you can imagine the ecliptic – the pathway of the planets – with the mind’s-eye.
Mars in front of Regulus’ constellation, Leo the Lion. Scan for Mars Sunday morning about two to three finger-widths above Regulus, remembering to hold your hand at an arm length when making measurements on the sky’s dome.
Want more? Have binoculars? If so, aim your binoculars at Jupiter to see the faint star Wasat of the constellation Gemini directly below Jupiter, as seen from the Northern Hemisphere. During the upcoming week, watch for Jupiter to move to the other side of this star. Also, try locating the star Asellus and the Beehive star cluster of the constellation Cancer the Crab.
Planets after sunset. You can also catch two planets at evening dusk. After sunset, if you’re in the Northern Hemisphere, look in the southwestern sky for Venus and Saturn. If you’re in the Southern Hemisphere, look more due westward. The Southern Hemisphere’s evening sky now, where it’s springtime, features the planets more above the sunset than to one side of it (as is our Northern Hemisphere perspective in autumn). People at more southerly latitudes (northwern tropics and Southern Hemisphere) can even catch the planet Mercury beneath Venus and Saturn at dusk and/or nightfall. Meanwhile, we in the Northern Hemisphere don’t have much chance of seeing Mercury. It’s buried in our horizon haze after sunset.
Bottom line: The moon is back in the predawn sky. Look east. The planets Jupiter and Mars are there, too. Jupiter is easy to see because it’s so bright. The moon is more or less between Jupiter and Mars on Sunday, September 29. The moon will move closer to Mars in the coming days.