First full moon of 2008 presents calendar oddity
6 comments Print Me Email to FriendTonight's Sky for Monday, Jan 21 2008
For us in North America, the moon turns full in the morning hours on Tuesday. For more on the exact time of the January full moon, check out today’s Earth & Sky radio show.
For general reference, you can say tonight is the full moon since full moon comes early tomorrow morning for us in the U.S. Because the moon shines opposite the sun in our sky around the date of full moon, tonight’s moon will behave like all full moons in rising around sundown and setting around sunup. The moon will shine close to the stars Castor and Pollux – the brightest lights in the constellation Gemini – all night long.
Because this first full moon of 2008 falls on January 22, we’re guaranteed to have 4 full moons in one season this year. Generally, only 3 full moons fall in any one season – unless the first full moon comes so early in a season that a 4th full moon falls just before the season’s end. This year, 4 full moons occur between the March 20 equinox and the June 21 solstice.
The 3rd of 4 full moons falling in the same season is sometimes called a blue moon. This happens on May 20, 2008. Every 19 years, the year’s first full moon recurs on January 22, foretelling the seasonal blue moon that’s to come on May 20 of the same year.
It was told to me by my father, many years ago, that a “blue moon” was the second full moon, in a given month… For example if the 1st full moon occurred on the 2nd of January, the “blue moon” would occur on the 30th/31st…
But as the saying goes…. Once in a blue moon …. your explanation, with 19 years seperation, does seem to be more of a rareity.
Does anyone know how often 2 full moons occur in any month(s)?
Tommy, by this definition (the second of two full moons in a given month), blue moons occur about every 30 months or so. We did a radio show back in May that has many good links: Is the 2007 blue moon on May 31?
There have been other definitions of a blue moon, some dealing with the atmosphere. One is the sighting of a full moon through bluish forest fire smoke. Do a Google search on “blue moon” and you will come up with tons of stuff, including my favorite, Blue Moon Beer
Larry S.
Denver
Tommy and Larry,
Every 19 years, the phases of the moon repeat themselves on or near the same calendar dates. That’s why the blue moon of May 20, 2008 (3rd of 4 full moons in one season) will repeat on May 20, 2027. However, we’ll have a number of seasonal blue moons before 2027. In fact, the next seasonal blue moon will fall on Nov 21, 2010. Generally, every 19 years, there are 7 seasons with 4 full moons.
As to the more modern definition of blue moon (2nd full moon in a single calendar month), 7 of 19 years have a blue moon by this definition of the term. Every 19 years, there are 235 full moons but only 228 calendar months. So these 7 extra full moons (235-228=7) have to share a month with another full moon. But Feb 2018 has no full moon whatsoever, so that’s another leftover full moon, giving a total of 8 blue moons (2nd full moon in a single calendar month) in the 19-year lunar period.
Bruce
Hi thanks for the info just a quick question, so on tuesday the full will be for us Canadians right? In what constellation will the full moon occur?
Manisha,
Yep, same as in the US. The moon will be in Leo, the Lion.
LS
Denver
Larry,
Just to double-check: isn’t the January 2008 full moon in front of the constellation Cancer the Crab? Next month, however – on the night of Feb. 20 – we’ll see the full moon (totality eclipsed, even) in front of the constellation Leo the Lion. We’ll see the totally eclipsed full moon right between the planet Saturn and the star Regulus, Leo’s brightest.
Bruce