Blue and Black Moons

[Ithilgore]

Merry meet all

The Blue Moon

When two full moons occur in the same calendar month, the second full moon is commonly defined as a blue moon. The full moon occurs every 29.53 days, so any month may have a second full moon with the exception of February, due to its maximum 29 days each leap year. On average, there’s one blue moon every 32.5644 months. The next blue moons will occur in the following year months,

2009 December
2012 August
2015 July
2018 January and March
2020 October

The definition of what a blue Moon is has changed over the years.

Old Rule - Based on the season

Because the number of Moon cycles in any given year is not exact number (12.3685), any lunar calendar (based upon moon phases) is in time going to drift out of step with the seasons. To compensate for this additional months were usually added when required, but they were often added based upon a given season. A season usually has three months and therefore three Moons. When an extra month and therefore extra Moon was added, it was done so usually just after the second month, then the Moon during this month was called the blue Moon. The old rule for the Blue Moon is that in any season (Spring, Summer, Autumn, Winter) that contains 4 full Moons, then the third one is the called the Blue Moon.

New Rule - Based on the month

This rule changed in 1947 due to a mistake. The author of an article in the Sky and telescope magazine incorrectly assumed that the above rule meant that for any month that contains two full Moons, then the second full Moon is a blue Moon. This definition is now the accepted definition.

The Black Moon

The night of the Black moon a very powerful time for craft work, the Black moon being a sort of dark sister to the Blue moon. Most people are familiar with the Blue moon, the Blue moon being the second Full moon to occur within a given calendar month. The Black moon is the name given to the second dark moon to occur within a calendar month. On average, there’s only one Black Moon every 32.5644 months. The next Black Moons (Universal Time) will be on,

2008 Aug 30 19 58
2011 Jul 30 18 40
2014 Jan 30 21 38, and Mar 30 18 45

Thirteen Moons

I am not sure why so many books often say there are 13 moon cycles per year. The tropical revolution period of the earth about the Sun is 365.242 days, there for dividing 365.242 by 29.53 (Moon’s orbit time) gives,

Number of full moons per year = 12.3685

This is closer to twelve than 13.

Merry part and brightest blessings
Philip (Ithilgore)

[wiccachicken]

Good post. I had a very good book that informed me of these blue and black moons. Thankyou for giving the dates aswell, I will actually mark these down in my diary Maybe I could go skyclad around my local countryside to celebrate haha!

[Heka]

ive never heard of a black moon before but it makes perfect sense. if your gonna celebrate the 2nd full moon then u shud be thinking of the 2nd darkd moon to.

thanks for the post

Blessings

Heka

[hedge*]

Thanks for that post Ithilgore - I love Moon Lore.

[Blazewind]

Very intersting post. Thank =you for sharing that with us.

[Serendipity]

The new rule about blue moons is the result of a mistake made in Sky & Telescope Magazine. An author wrote something poorly and so people got the impression that the second full moon in any given month was the blue moon.

Here is one site that discusses the misunderstanding:
http://www.skyandtelescope.com/observin ... 04131.html

There is more information about blue moons than can be found there though so here is some of that information.

Perhaps the oldest and most (technically) accurate use of the term Blue Moon is when it is used to describe a moon that in fact appears to be blue. Yes, you read that right. We’ve all seen a Harvest Moon which clearly appears orange up in the night sky so there is precedent for the phenomena of color change in the appearance of the moon.

A moon that appears blue in color happens when there is volcanic eruption, or a major forest fire, spews matter and gases into the air that cause a change in the light reflection from the moon and that is how the color appears to change.

Now, whatever method a person decides to use to determine the Blue Moon in your magical system that is fine, for myself I use the method based on the seasons (the old one) as it has logic and purpose to it in both a mundane and a magical sense. I think that logic and purpose and magic go hand in glove.
If a person decides he, or she, wants to use the seasonal method for calculating Blue Moons some of the information the person will need to pay attention to is:

A) How does the reference material note time? Is it in UT? Is it in EST (if you’re in the US)? Does the reference material include adjustments for Daylight Savings Time? Whatever time you use you’ll need to convert all times for all tables to one time and I personally suggest using your local time.

B) When does the season change, down to and including the minute?

C) When does the moon move into its full phase, down to and including the minute?
Once you have this information you simply sit down with a pen and piece of paper and plot the moons in their proper seasons.

The reason you need to be specific about the time the Solstice/Equinox happens and the time the full moon begins is because sometimes the events happen very close together with a matter of minutes determining whether a full moon begins in the last moments of one season of the first moments of a new season.

Whatever method you decide to use to calculate Blue Moons knowing how that method came into existence is, I think, important because it connects you more fully to your magic. All are equally valid because ultimately all of our magic stems from us and our feelings, and perceptions, about it.

When a season has four full moons instead of the typical three then the third of the four full moon is considered a blue moon. If a blue moon had not been added to the count of full moons then the old names would have eventually gotten out of sync with their appropriate season. For example a Seed Moon associated with planting in the “young year” would have shifted to other seasons and you would have had a Seed Moon at harvest time.

[ScarlettRose]

Yeah, thanks a lot for sharing this..
I really never thought about Black Moons before. That's very great to know.
Thank you (: Lovely post!