A rare alignment of the moon and three planets will give millions a reason to look up — and the view could leave stargazers smiling. The final major astronomical event of April will feature the moon shining alongside Venus,

Skywatchers can enjoy a celestial alignment of the crescent moon, Venus, and Saturn on April 25, with Mercury visible near the horizon.

Venus, Saturn and the moon will form a triple conjunction, appearing to look like a smiley face in a sky. Here's how and when to witness the rare event.