On the evening of May 24, 2012, the waxing crescent moon shines close to Castor and Pollux, the two brightest stars in the constellation Gemini the Twins. The moon is waxing toward a lunar eclipse on June 4. Finally, don’t forget to watch the bright planet Venus, as it drops into the sun’s glare.

Gemini? Here’s your constellation

People often refer to Castor and Pollux as “The Twins” but they aren’t really twins at all. At a distance of about 34 light-years, Pollux is the closest giant star to our solar system. It’s one of the very few giant stars in our galaxy known to have a planet.

Castor is farther away, at 52 light-years. It looks like a single star to the eye, but it’s actually six stars in one, all revolving around one another in an intricate dance.

Pollux on left. Castor on right. See the contrast in their colors? Pollux is golden, and Castor is white. (Warren Wilson College)

With binoculars, you might be able to discern Castor and Pollux’s contrasting colors. Pollux looks orange, while Castor appears white. An orange star has a relatively low surface temperature, indicating that Pollux is in the autumn of its years. On the other hand, a more youthful star – like Castor – displays a white color, a sure sign of this star’s higher surface temperature.

Meanwhile, tonight’s moon is in a waxing crescent phase. It’ll continue to wax larger until full moon in early June. Mark your calendar: this June 2012 full moon will feature a partial lunar eclipse. It’ll be visible throughout the Americas and Asia.

When you’re finished looking at the moon, Castor and Pollux, be sure to notice the planet Venus, still the brightest light besides the moon after sunset. Over the coming week, Venus will drop noticeably into the sun’s glare prior to the June 5-6 Venus transit – last one in this century! Venus is so bright that you can see it very near the sunset. And a lovely sight it is. You’ll need an unobstructed horizon, but if you have one it’ll be fun to watch until this wondrous planet, which has given us so much enjoyment in recent months, as it finally leaves the evening sky. The image below shows Venus near last night’s moon. It’s from our friend May Tama in Japan.

Moon and Venus on May 23, 2012 from EarthSky Facebook friend May Tama in Okayama, Japan.

Click here to expand image above

Bottom line: On the evening of May 24, 2012, the waxing crescent moon shines close to Castor and Pollux, the two brightest stars in the constellation Gemini the Twins. Mark your calendar for the June 4 lunar eclipse. Watch the bright planet Venus drop into the sun’s glare as it leaves the evening sky.

Castor is the fainter of two Twin stars

Pollux: Brightest star of the Twins

Lunar eclipse: Americas before sunrise, Asia after sunset June 4