Donald Trump is not only a cautionary tale for the American political system but also for how one should view Monday’s eclipse.

On Thursday, CNN’s Jim Acosta was discussing how to protect your eyes during the eclipse with corresponded Tom Foreman and used the former president’s actions during the 2017 eclipse as an example of what not to do.

“You should not look up at the eclipse. Don’t do that,” Acosta told viewers. ”That that will damage your eyes. The president of the United States did it some years ago.”

Foreman agreed that looking directly at the sun is “not a thing to do if you’re going to look at it,” before stressing the need for protective eyewear that is made specifically for viewing eclipses.

“Make sure they’re not scratched or wrinkled or anything that would let those harmful rays get in and damage your eyes,” Foreman added. ”Likewise, don’t try to look through a camera, telescope, binocular, sunglasses without other filters already in place on those, because those can just concentrate the light and they can still damage your eyes.”

You can see the exchange below, courtesy of Mediaite reporter Tommy Christopher.

Foreman noted that even the ancient Greeks were well aware of potential eclipse eye damage. However, Trump didn’t get the memo, as this video from 2017 notes (though an aide did tell him not to look as he was looking).

Acosta isn’t the only one using next week’s eclipse to shed new light on Trump’s eclipse peeping.

Late last month, Jimmy Fallon did a spoof commercial for “Trump Eclipse Glasses” that showed the former president gaping at the eclipse without protection.