RIVERSIDE (CBSLA.com) — If you plan on staying up all night on Christmas Eve drinking eggnog, go outside and gaze into the sky. You will see a lunar rarity before dawn on Christmas day, a UC Riverside astronomer said.

“Although it is not of astronomical significance, it is still a beautiful phenomenon,” UCR researcher Mario De Leo Winkler said.” This will be the first Christmas morning that will be paired with a full moon since 1977.”

Winkler oversees a NASA-sponsored program in the UCR Department of Physics and Astronomy. He said the moon will reach full phase at 3:11 a.m. Friday.

But you may miss it because it’s expected to be cloudy and rain on Friday morning. The next full moon on Christmas won’t occur until 2034.

The full moon will not be the only celestial event coinciding with Christmas.

“On Christmas Eve, a giant asteroid will be zooming past Earth,” he said. “The oddly named 2004-SD220 will zoom by at a distance of 6.8 million miles. That is 27 times farther away than the distance from the Earth to the moon. The asteroid is 1.3 miles in diameter – or 20 football fields – and is moving through space at 17 miles per second.”

Winkler said the solid mass “poses no risk to the planet. There is no chance it collides with Earth in any way.”

“We won’t see 2004-SD220 again until the year 2018,” the astronomer said.