The western sky is pretty crowded tonight. The Moon and the planets Venus and Mars join the usual lineup of stars, including the twins of Gemini and a busy star cluster known as the Beehive.

As darkness falls, the Moon stands pretty much due west, more than a third of the way up the sky. Mars is close below it, and looks like a fairly bright orange star. Venus is off to their lower right — the brilliant “evening star.”

All three of these bodies are in constant motion against the background of stars, which are much, much farther away. The Moon’s motion is obvious from one night to the next — it moves by more than the width of your fist held at arm’s length. Tonight, the star cluster M44 is close to its left. Through binoculars or a telescope, the cluster looks like a bunch of angry bees buzzing around their hive, so it’s also known as the Beehive. By tomorrow night, the Moon will have moved well away from the cluster.

Venus and Mars move more slowly, but it doesn’t take long to notice a difference — especially when they’re close to such prominent stars as Pollux and Castor, the twins of Gemini.

Pollux is directly above Venus tonight, with Castor to its right. By late next week, though, Venus will line up side by side with the bright stars. At the same time, Mars will be passing directly in front of the Beehive — a long way from its current location.

Tomorrow: Patching up the first American space station.
 

Script by Damond Benningfield