For the week including September 24, 2010

HARVEST MOON

The full moon of September 23rd was the first full moon on the autumnal equinox in twenty years. On an equinox, day and night are equal in length, providing a rare coincidence of the Sun setting and the Moon rising at the same time. Since colonial times, the continued light provided to farmers earned it the title of Harvest Moon.

The title itself can be traced to the Farmer’s Almanacs of New England which would publish calendars that indicated the days on which full moons would occur along with the names that the moons were called by various Indian tribes.

January’s full moon, the Wolf Moon, was a reminder that the cold weather would draw these predators closer to farms.

February’s wintry weather was associated with the Snow Moon.

March’s full moon, the Crow Moon, recalled that the end of winter came with the cawing of crows.

The grass turned green again under April’s Grass Moon.

Spring was in full bloom under May’s Flower Moon.

The Algonquin Indians harvested strawberries just after June’s Strawberry Moon.

July’s stormy season was indicated by the Thunder Moon.

Wheat would near its full height under August’s Grain Moon.

September’s Harvest Moon is the best known moon of them all and has been celebrated since ancient times.

The Hunter’s Moon of October was a reminder to stock the larder for winter.

Cold weather arrived under November’s Frost Moon.

Midwinter and the shortest day were marked by December’s Long Night Moon.

The timing for each calendar month’s moon was based upon there being only three full Moons each season, one for each of its months. But, very rarely, the lunar cycle would allow a fourth full Moon to sneak into a season. If left uncorrected, the extra moon created a problem by pushing the remaining moons of the year out of order. The almanac editors worked out a formula whereby a season with four full moons would have its third full moon called a blue moon and that solved the problem of keeping the timing and order of the moons correct. The term itself, “blue moon” has been a common expression of rarity since Shakespeare’s days.

The almanac’s definition of a blue moon worked well until 1946 when Sky & Telescope magazine published a story on the subject. The author of that story didn’t understand the formula for determining a blue moon and just created a new, simpler one: if a month had two full moons in it, the second one would be called a blue moon. Although this mistaken explanation lacked the obtuse charm of the original, it has become the more commonly used definition. But how might this affect blue moon chasers? Well, if you go by the Farmer’s Almanac definition, then the full moon on November 21st would be blue because it would be the third full moon of the autumn of 2010 which has four full moons. On the other hand, if you’re just looking for a month with two full moons in it, then August of 2012 will do with full moons on the 2nd and 31st.

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