As our planet revolves around the sun, the sun appears to shift its position gradually from day to day, tracing out a path against the background of more distant stars. The path that marks the sun's journey is called the ecliptic. The ecliptic passes through a band of 12 constellations called the zodiac. Because the planets and moon move in the ecliptic plane, or the same flat plane as Earth's orbit, we will always find them in the constellations of the zodiac near the ecliptic.
This week, stargazers can observe the moon pass along the ecliptic through the zodiac constellations of Aquarius, Pisces and Taurus. Tonight the thin crescent moon will be located in Aquarius, 20 degrees above the west-southwestern horizon. The crescent moon will climb into Pisces by Wednesday evening and reach first-quarter phase on Friday. The waxing gibbous moon will move into Taurus over the weekend and sit approximately 15 degrees to the upper right of Aldebaran, Taurus' brightest star, on Sunday.