Comet Pons-Brooks: How and when to see it

Time is running out for you to spot Pons Brooks, the Devil's Horned Comet that appears before you once every 71 years. The last time people were seen on Earth was in the 1950s, the comet is prone to unexpected explosions or flares in brightness.

“It's an extraordinary comet,” said Elliot Herman, a retired biotechnologist at the University of Arizona and an astrophotographer who has been tracking Ponce Brooks for months. “The comet not only becomes brighter as it approaches the Sun, but it also changes radically day after day,” he said.

The comet, a green ball of ice, caught the public's attention last July, when it appeared to have sprouted horns after exploding through its dusty atmosphere. Some likened the comet's shape to the Millennium Falcon spacecraft used by Han Solo and Chewbacca in the Star Wars film series. The comet experienced a series of additional explosions in the fall, including one on Halloween.

By December, Pons Brooks had hints of a tail. This feature became longer and more pronounced in early March as the comet sailed closer to the sun. Some had hoped it would glow enough to be seen during the total solar eclipse on April 8, but it was not visible to the naked eye during the event.

There are only a few days left to see Pons Brooks before it reaches the point where it is closest to the sun on April 21. At that point, known as perihelion, the comet will be blocked from view by sunlight.

To see the comet, Bill Cook, an astronomer who leads NASA's Meteorite Environment Office, recommends going out at twilight and scanning the western horizon with binoculars or a telescope. Look for Jupiter, the brightest object in the night sky other than the moon. Ponce Brooks will be at his bottom left.

But don't expect to see its distinctive devil horns. “The horns are gone now,” Dr. Cook said. “It looks more like the typical comet that people imagine.”

In about a week, the comet will disappear below the horizon and disappear from the northern sky. People in the Southern Hemisphere may be able to spot the comet during May, although it will appear darker.

Then, Pons Brooks will bid farewell to stargazers on Earth for another seven decades, as he embarks on another journey around our sun.