By Todd C. Frankel
MARYSVILLE – According to the calendar hanging in the back office at Carr Ace Hardware, there was no full moon in the sky on Halloween.
And October did not feature a blue moon, contrary to widespread reports.
The calendar, a promotion for Hilton Pharmacy down the street, insists the full moon arrived today.
But that calendar – and most likely the calendar on your desk or wall, too – is wrong.
“I had no idea,” said store owner Darlene Scott.
A quirky coincidence of time zones, astronomical events and the bias of calendar makers has created confusion over whether the full moon falls on Wednesday, Oct. 31, or today, Nov. 1.
The answer is not an easy one.
A full moon occurs when the moon is exactly 180 degrees opposite the sun. The earth sits in between. At that moment, the sun fully illuminates the moon.
On the day of a full moon, it’s possible to see the moon and sun rising at opposite points in the sky, said John Armstrong, a University of Washington graduate student studying for his Ph.D. in astronomy.
“When you watch a sunset toward the west, you should see the moon at the same point in the east,” Armstrong said.
The second full moon in any month is called a blue moon. It’s rare, occurring once every 2.5 years, because lunar phases run 29.5 days.
According to the U.S. Naval Observatory in Washington, D.C., the exact moment of the full moon occurred on Wednesday for most of the United States. But in the astronomical sense, it happened today.
According to them, the full moon appeared on the West Coast at 9:41 p.m. Wednesday. People in the Mountain and Central time zones also enjoyed a late Halloween blue moon.
But on the East Coast, there was no blue moon. The full moon didn’t arrive until 12:41 a.m. today, meaning their blue moon comes later this month.
Confused? Well, making matters worse, astronomers rely on Universal Time, or Greenwich Mean Time. Under that system, the full moon occurred at 5:41 a.m. GMT today. So astronomers, too, consider November the blue moon month.
This is too much detail for most calendars, which tend to note lunar phases with tiny circular icons. Most calendars seem to default to using Eastern or Universal time zones for placing events. That is why almost all calendars declare today to be the day of the full moon.
On this coast at least, they’re wrong.
“I guess they forgot about us West Coasters,” Scott said.
Not that it matters. To the naked eye, the moon will appear full for a couple of more days, Armstrong said.
You can call Herald Writer Todd C. Frankel at 425-339-3429 or send e-mail to firstname.lastname@example.org.