If skies remain clear across Maryland, as they should, we may be able to catch an unusual gathering of celestial objects in the western sky after sunset on Sunday.

UPDATE: Here's a gorgeous shot of this event.

The first of the crowd to appear will be a slender crescent moon, just above the western horizon about 45 minutes after sunset. Sunset for Baltimore on Sunday will be at 7:55 p.m. The moon will be barely 24 hours past "new," and just about as slim a sliver of moon as you will ever see.

Next, as the dusk continues to deepen, just below the moon, you should be able to see a tiny "star" pop into view. Binoculars will help while the sky remains fairly bright. It's not actually a star, but the always-elusive planet Mercury, which is about as far to the east of the sun this month as it gets, and therefore easiest to spot.

Now, as the darkness gathers, and the moon and Mercury sink closer to the horizon, watch immediately below the moon for a delicate cluster of stars called the Pleiades to appear. This star cluster is called Subaru by the Japanese. It's also known as the Seven Sisters because it appears to the unaided eye to contain seven stars in a close grouping. With binoculars, many more appear. In a small telescope, there are hundreds. They're all in a tight bunch, fairly close by astronomical standards - about 415 light years away. (One light year - the distance light travels in a year - is about 5.9 trillion miles.) 

The moon, by comparison, will be a mere 228,000 miles away on Sunday, while Mercury currently stands about 82.7 million miles from Earth. Here's the sky map, from NASA.