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Paul Unwin
2001-Nov-01, 09:50 PM
There was some talk about how the full moon last night was the first one to occur on Halloween since, I believe 1946. I then heard on the radio that the moon this Halloween was the first blue-moon to occur on Halloween since (again, I believe) 1946. Just as soon as they said this, I realized that any full moon that fell on October 31st would be a blue moon, given that the last full moon would had to have happened on the 3rd.

Anyway, in various places I read or heard that the next Halloween full moon will occur in 2020. Why was 55 years since the last one, but only twenty years until the next?

ljbrs
2001-Nov-02, 12:08 AM
There was no *Blue Moon* on Halloween. NONE!! The *Blue Moon* occurred after midnight, making it a full moon (99.7%) on November 1, rather than the (99.6%) October 31, before midnight. There will be a *Blue Moon* during November, however, on November 30, making it the second full moon (99.9%) during November 2001.

Whoever told anybody that there was a *Blue Moon* on October 31, was mistaken... They should have checked with a reputable source. I checked with a number of reputable sources, including *The Sky* software on my Casio Cassiopeia Pocket PC, as well as in others.

It is so silly to insist upon being right, naturally, so I will accept *silly* as my state of mind.

ljbrs /phpBB/images/smiles/icon_biggrin.gif /phpBB/images/smiles/icon_biggrin.gif /phpBB/images/smiles/icon_biggrin.gif

Hale_Bopp
2001-Nov-02, 02:02 AM
Actually, I believe could both have been correct depending on where you lived. The full moon was so close to midnight, that is occurred on October 31st in some time zones and November 1st in others. The full moon occurred at 11:41 pm central standard time on October 31st. That means it was 12:41 am on November 1st in the eastern time zone. We had a full moon on October 31st in Illinois, but they didn't across the border in Indiana, or anywhere in the eastern time zone.

Consequently, the east coast enjoys a blue moon in November that we don't.

Rob

David Hall
2001-Nov-02, 04:33 AM
Of course, it depends on what your definition of Blue Moon actually is. The story of this term is actually very interesting. Check out the facts at:

http://www.quinion.com/words/topicalwords/tw-blu2.htm

Paul Unwin
2001-Nov-02, 01:47 PM
On 2001-11-01 21:02, Hale_Bopp wrote:
Actually, I believe could both have been correct depending on where you lived.

That makes sense. I live in Seattle, so I had a blue moon too. It's pretty funny to think that my parents in Michigan had one full moon last month when I had two.

ljbrs
2001-Nov-03, 12:13 AM
Perhaps the blue moon which occurs at the Royal Observatory Greenwich would be the only one which counts. Of course, since I am a complete narcicist, ONLY MY BLUE MOON IS OF ANY IMPORTANCE AT ALL... Then again, there are varying dates for the full moons, depending upon the location on Earth. So my blue-moon month will not be everybody's blue-moon month. Perhaps some folks will not have a blue moon at all. Drat! Then again, since the scientists are always fooling around with leap seconds, etc., time is always relevant to the location and to the decisions of the time setters.

On the other hand, different countries have different calendars, so the blue moon does not really exist universally. since I consider that MY BLUE MOON IS THE ONLY BLUE MOON WHICH COUNTS, and that for you, YOUR BLUE MOON IS THE ONLY BLUE MOON WHICH COUNTS FOR YOU, we can *duke it out* sometime. Choose your weapons...

ljbrs /phpBB/images/smiles/icon_smile.gif /phpBB/images/smiles/icon_wink.gif /phpBB/images/smiles/icon_biggrin.gif

SeanF
2001-Nov-05, 12:48 PM
On 2001-11-02 19:13, ljbrs wrote:
Perhaps the blue moon which occurs at the Royal Observatory Greenwich would be the only one which counts. Of course, since I am a complete narcicist, ONLY MY BLUE MOON IS OF ANY IMPORTANCE AT ALL... Then again, there are varying dates for the full moons, depending upon the location on Earth. So my blue-moon month will not be everybody's blue-moon month. Perhaps some folks will not have a blue moon at all. Drat! Then again, since the scientists are always fooling around with leap seconds, etc., time is always relevant to the location and to the decisions of the time setters.

On the other hand, different countries have different calendars, so the blue moon does not really exist universally. since I consider that MY BLUE MOON IS THE ONLY BLUE MOON WHICH COUNTS, and that for you, YOUR BLUE MOON IS THE ONLY BLUE MOON WHICH COUNTS FOR YOU, we can *duke it out* sometime. Choose your weapons...

ljbrs /phpBB/images/smiles/icon_smile.gif /phpBB/images/smiles/icon_wink.gif /phpBB/images/smiles/icon_biggrin.gif


That's why I prefer the 'original' definition of a "Blue Moon" -- third full moon in a season with four.

Since the change of the seasons are also world-wide, those Blue Moons are Blue Moons everywhere.

Not to mention much more rare than the two-in-a-calendar-month variety . . .

GrapesOfWrath
2001-Nov-05, 01:23 PM
Are they really that much more rare? Just a WAG would say that under the first definition, the first moon would have to occur during the first two days of the month, so the odds are about 2/30, or about .067. Under the second definition, the first moon would have to occur during the first 6 days of the season, so 6/91--which is about 2/30.

SeanF
2001-Nov-05, 01:50 PM
On 2001-11-05 08:23, GrapesOfWrath wrote:
Are they really that much more rare? Just a WAG would say that under the first definition, the first moon would have to occur during the first two days of the month, so the odds are about 2/30, or about .067. Under the second definition, the first moon would have to occur during the first 6 days of the season, so 6/91--which is about 2/30.


Hmm . . . you got me thinking now. Are they really more common?

What you're quoting are the odds of having a Blue Moon in any given month versus the odds of having a Blue Moon in any given season. But there are three times as many months in a year, as there are seasons . . . so the odds of having a 'monthly' Blue Moon in any given year would be about three times the odds of having a 'seasonal' Blue Moon in that year?

But that doesn't seem right, either . . .

At any rate, maybe they're not 'much' more rare, but you certainly don't get two of them within two months like you did with the 'monthly' Blue Moon in Jan-Mar 1999!

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*** EVERYTHING BELOW HERE ADDED AT 10:40 CST ***

Okay, on more thinking, the 'seasonal' Blue Moon is only slightly less common than the 'monthly' Blue Moon.

Generally speaking, every 'monthly' blue moon is followed by a 'seasonal' one approximately one year later, with one exception:

Occasionally you have two full moons in January and two in March in the same year (1999 and 2018 have this). In that case, there will generally be a 'seasonal' Blue Moon in February of the next year, so you have a pair of 'monthly' Blues matching up with a single 'seasonal.'

I figure there's maybe 10 'seasonal' Blues for every 11 'monthly' Blues . . .

_________________
SeanF

<font size=-1>[ This Message was edited by: SeanF on 2001-11-05 10:05 ]</font>