Hi All,
I ran across an article in the Sydney Morning Herald yesterday (28122009) proclaiming that a "Blue Moon" occurs on New Years Eve, December 31st 2009 -- being the second full moon of the month of December.
The item is here:
http://www.smh.com.au/national/somet...1227-lgae.html
There is a some dispute as to the exact meaning of the term "Blue Moon". The most popular meaning is a 2nd full moon in a calendar month. However, the most likely strictly correct one (but not well known) is explored in an article in the 1999 edition of Sky & Telescope Magazine by Phillip Hiscock, relying on the first known usage of the term in the Maine Farmers Almanac, where a "Blue Moon" was the defined as the third Full Moon within a season that contained four Full Moons.
In fact for
all Australian time zones (according to either definition) this New Year's Eve will not be a Blue Moon because Full Moon is at 19:14 UTC on 31st December and it will therefore occur at 6.14am AEDST on the 1st of January 2010. For 3/4ths of the world, they will get a Blue Moon on December 31st -- but not Australia. ie all time zones between UTC +6hrs and +11 hrs will
not have a blue moon, all other time-zones will have a blue moon on New Year's Eve.
Our (Australian) "Blue Moon" will actually occur on 30 January 2010 (by the first and most popular definition of the term Blue Moon).
But in looking at that question, another arose -- February 2010. If a "blue moon" is uncommon or rare, even rarer (much, much rarer in fact) is a calendar month
without a Full Moon at all. These can only occur in the month of February because a Synodic Month (for practical purposes here), is the period between two full moons and is just over 29.5 days on average. All other calendar months have 30 or 31 days -- longer than the Synodic Month and so therefore must contain at least one Full Moon.
Therefore in the month of February 2010,
using Australian time zones, there will be
no Full Moon at all. Great news for all deep-sky observers and astro-imagers (just kidding!).
Full Moons are 5:18pm AEDST 30th January 2010 and then 3:38am AEDST 1st March 2010.
How rare is that?? Much, much rarer than a Blue Moon that happens on average every 2.5 years-odd.
What's more, we'll get a second Blue Moon in a calendar year (according to Australian Time Zones) at the end of March. So Jan 2010 we get two Full Moons, February 2010 -- no Full Moon, then March 2010 -- two Full Moons again (using the most popular definition). Wow!
So, when was the last February without a Full Moon?
I'm waiting for someone to tell me ...!
Best,
Les D