Western North Carolina stargazers will be able to witness a rare astronomical phenomenon this month when four of the five planets visible to the naked eye can be observed close together in the early morning sky.

That’s the word from Paul Heckert, professor of astronomy and physics at Western Carolina University. Mars, Jupiter, Venus and Mercury will be very close together just above the southeastern horizon in the predawn sky during May, Heckert said.

“For sky-watchers in Western North Carolina, the planets will be low in the sky, and anyone wanting to observe them will need a very good southeastern horizon, such as on a mountaintop or high on a southeastern slope,” he said. “Also, because they will be low, the fainter planets could be lost in the glare of the morning twilight without binoculars or other optical aid.”

Jupiter and Venus will be the two brightest objects visible, he said. In the second half of May, Jupiter will be easy to spot and higher than Venus in the sky.

Venus, Mercury and Mars have their closest approach on the morning of May 21, a close grouping that will last until the morning of May 25. For the rest of May, the four planets will move further apart.

“Providing one last treat for stargazers, the thin waning crescent moon will pass close to these planets from May 29 to May 31,” Heckert said. “The fifth naked-eye planet, Saturn, will be visible all night in May, but will be setting in the west in the twilight hours, not in the east where the other planets can be seen.”