OUR LUNACY: So exactly how many moons – full, new, or otherwise
– are there in a month?

Yesterday, we rehashed an RTS item about a “blue moon” this
month, a rare occurrence when our yearly calendar overlaps with the
lunar calendar.

As we got additional information on the subject, however, we
realized it’s not as simple as it seems.

Corky Galloway of Tucson, Ariz., gives us the conventional
thinking: “A normal month has only one full moon due to the 28-day
cycle. This month June of 2007 will have two full moons. This is
rare and the second full moon in any one month is known as a ‘blue
moon.’ We will have a full moon on the thirtieth. The first was on
the first of June. Yes, they only happen once in a blue moon, i.e.,
rarely… “

But Carol Zintz refines that a bit noting, “The average length
of time between full moons is 29.5 days. There will be only 41
months per century that have a second full moon.”‘

Check out this further distinction from Dave Dewyer of Eldred:
“Traditionally, a ‘blue moon’ would be the third full moon in a
quarter that has an extra (total of four) full moons. These
quarters are not based on the calendar year (Jan. 1 to Dec. 31) but
instead on a tropical year that starts and ends on the winter
solstice (on or about Dec. 21). These quarters equate roughly to
the four seasons.”

“A more recent definition for a blue moon – a second full moon
in a calendar month – can be attributed to a mistake in an article
in the March 1946 edition of Sky & Telescope magazine. It was
easier to comprehend, stuck with the media and has gained
popularity.

“The moon completes a full cycle in approximately 29.5 days.
Here in this part of the woods May had two full moons – the first
on May 2 the next on May 31 at 9:04 p.m. Eastern Daylight Time. The
only full moon here this month will be June 30.”

Many calendars, he added, likely has the moon phases as observed
at the Greenwich, England (Greenwich Mean Time or Universal Time).
That is four hours ahead of us here this time of year – hence the
June 1 (1:04 a.m. GMT) instead of May 31.”‘

A bit more on this subject tomorrow.