It’s the kind of timing that makes kindergarten teachers and 911 dispatchers cringe: This week’s full moon will appear on Friday the 13th.

While superstitiously known as an unlucky day, this Friday will be lucky for skywatchers who have been waiting for this month’s Harvest Moon.

While the moon won’t be considered technically “full” until the very wee hours of Saturday, it will appear full when it rises Friday night. It will look full again on Saturday and Sunday evenings.

So why is this timing so special? According to Newsweek, if you miss your chance at seeing a Friday the 13th full moon, you’re going to have to wait another 30 years.

“It is actually quite rare for the whole of the United States to experience a full moon on the date of Friday 13. The last time this happened was October 13, 2000, and it won’t occur again until August 13, 2049,” the news magazine said.