[rollei_list] Re: OT - Definition of "Blue Moon" (was: Selenium Light Meters)

On Saturday, April 30, 2005, at 02:18  PM, Jerry Lehrer wrote:

> Peter,
>
> FYI, a "Blue Moon" means refers to a month in which there are TWO full 
> moons.

 From <http://www.infoplease.com/spot/bluemoon1.html>:

[QUOTE]

What is a Blue Moon?

There are in fact two definitions for a blue moon. According to the 
more recent definition, a blue moon is the second full moon in a 
calendar month. For a blue moon to occur, the first of the full moons 
must appear at or near the beginning of the month so that the second 
will fall within the same month (the average span between two moons is 
29.5 days). July 2004 will have two full moons: the first on July 2, 
the second on July 31 - that second full moon is called the blue moon.

The Other Kind of Blue Moon

An older definition for the blue moon is recorded in early issues of 
the Maine Farmer's Almanac. According to this definition, the blue moon 
is the third full moon in a season that has four full moons. Why would 
one want to identify the third full moon in a season of four full 
moons? The answer is complex, and has to do with the Christian 
ecclesiastical calendar.

Some years have an extra full moon - thirteen instead of twelve. Since 
the identity of the moons was important in the ecclesiastical calendar 
(the Paschal Moon, for example, used to be crucial for determining the 
date of Easter), a year with a thirteenth moon skewed the calendar, 
since there were names for only twelve moons. By identifying the extra, 
thirteenth moon as a blue moon, the ecclesiastical calendar was able to 
stay on track.

For a fuller explanation see 
<http://www.inconstantmoon.com/cyc_blue.htm>. For more background 
information on the controversy over the two definitions of blue moon, 
see the Sky and Telescope article, "What's a Blue Moon?" In it they 
explain how the two different definitions of a blue moon came about - 
including their own role in introducing the second, modern definition.

[END QUOTE]

Cheers,

Ardeshir <http://homepage.mac.com/ardeshir>

















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