The full moon on Friday the 13th is a sight you will want to remember, since it isn't going to happen again until the year 2049, astronomers say.
The rarity of a Friday the 13th full moon is because a lot of variables have to coincide and line up just right: The day of the month, the day of the week, and the phase of the moon.
The last time all three landed together was Oct. 13, 2000.
Such a full moon in June is sometimes referred to as a "strawberry moon" because is comes near the traditional strawberry harvest time, or more often a "honey moon" after the golden hue it takes on because of its position low in the sky, the result of occurring near the summer solstice.
How uncommon is it? The odds of a full moon occurring on a Friday the 13th are 5.81 percent, which works out at about one occurring every 20 years or so.
The moon reached its fullest at 12:11 a.m. EDT. Technically, of course, that means people in the Pacific, Mountain and Central time zones will miss out on the experience, since they'll still be in late Thursday for the "full" moon.
Both Friday the 13th and full moons are involved in superstitious beliefs held by many people, who may feel the present event is a double whammy.
"In the U.S. there are millions and millions of people who just want to stay home and not take any chances on either one of these -- Friday the 13th or a full moon -- and here they are both together," says psychologist Mike McKee with the Cleveland Clinic in Ohio.
Such beliefs about the moon have even entered the language, with both "lunacy" and "lunatic" originating from the Latin word for the moon, "lunar."
Despite such beliefs, there's been no scientific basis for any link between a full moon and people's behavior.
A study in 1993 found no correlation between a full moon and any increases in psychiatric disturbances, hospital admissions or crime rates.
Full moons occur when the sun and moon are on opposite sides of the sky when seen from the vantage point of the Earth.
This gives observers on Earth a view of the moon's hemisphere in full illumination.
Sky watchers making notes in preparation for the next chance to view a Friday the 13th full moon should break out their 2049 calendars and put a big red circle around Aug. 13.
