Venus is glistening in the west at sunset, and by the end of the month it is closing in on a near encounter with Jupiter. In the meantime, the crescent moon will slide through the same stretch of evening sky on May 17, May 18, May 19 and May 20, giving stargazers a changing view each night.

Shortly after sunset on May 17, the moon may be visible very low in the west. On May 18, it will appear not far from Venus, even though the two will still be separated by 124 million miles. By May 19, the moon will sit about midway between Jupiter and Venus, and on May 20 it will be above Jupiter, now a significantly thicker crescent.

The sequence matters because the view is happening right now, during a brief spring window when the evening planets are easy to spot and the moon keeps shifting position night by night. For observers, that makes this week more than a pretty sky. It is a moving map of the solar system, with one bright point after another marking the path.

Dennis Mammana said the trio appears low enough in the sky at dusk to frame the scene with a foreground subject, and he said a regular camera or smartphone will do fine for photographing the spectacle. He also said binoculars may help observers see the moon and Venus pair on May 18. “That brilliant light now glistening in the west at sunset is again the ‘star’ of the show,” he said, adding, “For a really amazing view, check out the pair through binoculars!”

Venus, Jupiter and the moon are celestial wanderers, and their positions keep changing because they orbit the sun and Earth. What looks like a tight grouping in the sky is only an illusion, created by the fact that human eyes cannot see true depth in the cosmos. That is why the planets can seem to line up so neatly even when they are vastly different distances apart.

The best night to catch the shifting scene may depend on the weather, but Mammana said, “I hope your skies are clear this week so you can enjoy the planetary sky show.” If they are, the moon tonight and over the next few evenings will trace a simple path that is easy to follow and hard to miss.