August 2ed, 2012

 

 

 

 

 

 

 

 

 

The saying “once in a blue moon” refers to something that’s exceedingly rare. But in Los Angeles you’ll have two chances to see this lunar occurrence Friday, when a so-called blue moon comes into view.
The first opportunity will be Friday morning — yes, the morning — as the blue moon is setting for the day, said Anthony Cook, astronomical observer at Griffith Observatory. Look for the early-morning blue moon between 6:30 and 7 a.m. PDT, he said.

Later in the day, you’ll get a second chance to see the blue moon, when it rises at 7:13 p.m. PDT.

So what is a blue moon? It’s the second full moon within one calendar month.

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The moon isn’t actually blue. And it might even take on an orange hue as it starts to rise in the sky, Cook said. If anything, the Friday night moon will most likely appear an especially brilliant white.

“There’s nothing unusual really about the moon itself,” Cook said. “It will look like the usual moon.”

The genesis of the term “blue moon” is unclear.

“It’s not really certain” where it came from, Cook said. “Why ‘blue’ was chosen isn’t really known for sure.”

There are, on some occasions, atmospheric conditions that could produce a blue-looking moon, he said. And it’s believed that such conditions sometimes took place at the same time as the second full moon, perhaps leading to the moniker.

A blue moon occurs because the average lunar cycle is 28 to 29 days long. That’s why most months see just a single full moon.

The average month, however, is about 30 days long. “As a result, the lunar cycle gets out of phase with the calendar,” Cook said. “If you have a full moon right at the beginning of the month, you can get one at the end of the month.”

The last time a blue moon occurred was December 2009. “The next time will be on July 31, 2015,” Cook said.

He added that there is another definition of “blue moon,” one that comes from the Farmer’s Almanac. When four full moons occur during the course of a single season, the third of those is referred to as the blue moon, Cook said.

“That kind of full moon is just as rare as a second full moon in a month,” Cook said. “It also occurs every two or roughly three years.” The next seasonal blue moon will occur in August 2013.

 

Black Moon

In astronomy, the term black moon is not well known nor frequently used. As a consequence it has no accepted definition, but seems to have occasionally been applied to at least four different situations:

1. the absence of a new moon or dark moon in a calendar month;

2. the absence of a full moon in a calendar month;

3. either the third or the fourth new moon or dark moon in a season that has four of them (a season normally has only three). This is in analogy to the term blue moon which is the third full moon in a season that has four;

4. the second occurrence of a dark moon or new moon in a calendar month; this in analogy to an improper use of the term blue moon which sometimes is applied to the second full moon in a calendar month. and any magic worked during that period is deemed to be especially powerful.

Other Names for a Black moon are:

Dark Moon 
Black Moon 
Secret Moon 
Spinner’s Moon 
Finder’s Moon

Black Moon is a reference to witchcraft which bears no significance to astronomy. There is a range of, often contradictory, definitions of a black moon, some suggesting it is when there are two dark cycles of the moon in any given calendar month, and others where no full moon is present in a calendar month, being contradictory as one can only ever happen in a February, and the other can only ever occur in any other month. It is treated by wicca as a powerful astrological period in which any magical works performed would be more effective.

It has also occasionally been applied to at least four different situations:

Other names

In myth and folklore the full moon of each month is given a name. In many cases the waxing moon and waning moon are also given names. There are many variations, but the following list gives the most widely known names:

• January - Wolf moon, Cold Moon, Chaste Moon
• February - Snow moon
• March - Sap moon
• April - Growing moon
• May - Flower moon
• June - Mead moon
• July - Hay moon
• August - Corn moon
• September - Harvest moon
• October - Hunter’s moon, Blood Moon, Falling Leaf Moon
• November - Beaver moon, Mourning Moon
• December - Winter moon

Black Moons:

We Just Had a Black Moon this Year.

                                  Calendar

                             2012
        Full Moon                              New Moon
  Mon, Jan  9, 2012   2:32 AM     Mon, Jan 23, 2012   2:41 AM
  Tue, Feb  7, 2012   4:56 PM     Tue, Feb 21, 2012   5:37 PM
  Thu, Mar  8, 2012   4:41 AM     Thu, Mar 22, 2012   9:39 AM
  Fri, Apr  6, 2012   2:20 PM     Sat, Apr 21, 2012   2:20 AM
  Sat, May  5, 2012  10:36 PM     Sun, May 20, 2012   6:48 PM
  Mon, Jun  4, 2012   6:12 AM     Tue, Jun 19, 2012  10:02 AM
  Tue, Jul  3, 2012   1:51 PM     Wed, Jul 18, 2012  11:24 PM
  Wed, Aug  1, 2012  10:27 PM     Fri, Aug 17, 2012  10:54 AM
  Fri, Aug 31, 2012   8:57 AM     Sat, Sep 15, 2012   9:10 PM
  Sat, Sep 29, 2012  10:18 PM     Mon, Oct 15, 2012   7:02 AM
  Mon, Oct 29, 2012   2:50 PM     Tue, Nov 13, 2012   5:08 PM
  Wed, Nov 28, 2012   9:47 AM     Thu, Dec 13, 2012   3:42 AM
  Fri, Dec 28, 2012   5:22 AM     Fri, Jan 11, 2013   2:45 PM

                             2013
        Full Moon                              New Moon
  Sat, Jan 26, 2013  11:40 PM     Sun, Feb 10, 2013   2:22 AM
  Mon, Feb 25, 2013   3:28 PM     Mon, Mar 11, 2013   2:54 PM
  Wed, Mar 27, 2013   4:30 AM     Wed, Apr 10, 2013   4:38 AM
  Thu, Apr 25, 2013   3:00 PM     Thu, May  9, 2013   7:31 PM
  Fri, May 24, 2013  11:27 PM     Sat, Jun  8, 2013  10:58 AM
  Sun, Jun 23, 2013   6:33 AM     Mon, Jul  8, 2013   2:15 AM
  Mon, Jul 22, 2013   1:16 PM     Tue, Aug  6, 2013   4:51 PM
  Tue, Aug 20, 2013   8:45 PM     Thu, Sep  5, 2013   6:36 AM
  Thu, Sep 19, 2013   6:12 AM     Fri, Oct  4, 2013   7:34 PM
  Fri, Oct 18, 2013   6:37 PM     Sun, Nov  3, 2013   7:49 AM
  Sun, Nov 17, 2013  10:16 AM     Mon, Dec  2, 2013   7:22 PM
  Tue, Dec 17, 2013   4:29 AM     Wed, Jan  1, 2014   6:15 AM

                             2014
        Full Moon                              New Moon
  Wed, Jan 15, 2014  11:53 PM     Thu, Jan 30, 2014   4:40 PM
  Fri, Feb 14, 2014   6:54 PM     Sat, Mar  1, 2014   3:02 AM
  Sun, Mar 16, 2014  12:10 PM     Sun, Mar 30, 2014   1:48 PM
  Tue, Apr 15, 2014   2:45 AM     Tue, Apr 29, 2014   1:17 AM
  Wed, May 14, 2014   2:18 PM     Wed, May 28, 2014   1:42 PM
  Thu, Jun 12, 2014  11:13 PM     Fri, Jun 27, 2014   3:10 AM
  Sat, Jul 12, 2014   6:27 AM     Sat, Jul 26, 2014   5:42 PM
  Sun, Aug 10, 2014   1:11 PM     Mon, Aug 25, 2014   9:12 AM
  Mon, Sep  8, 2014   8:39 PM     Wed, Sep 24, 2014   1:13 AM
  Wed, Oct  8, 2014   5:50 AM     Thu, Oct 23, 2014   4:56 PM
  Thu, Nov  6, 2014   5:23 PM     Sat, Nov 22, 2014   7:32 AM
  Sat, Dec  6, 2014   7:27 AM     Sun, Dec 21, 2014   8:36 PM

                             2015
        Full Moon                              New Moon
  Sun, Jan  4, 2015  11:53 PM     Tue, Jan 20, 2015   8:15 AM
  Tue, Feb  3, 2015   6:09 PM     Wed, Feb 18, 2015   6:49 PM
  Thu, Mar  5, 2015   1:06 PM     Fri, Mar 20, 2015   4:38 AM
  Sat, Apr  4, 2015   7:07 AM     Sat, Apr 18, 2015   1:59 PM
  Sun, May  3, 2015  10:44 PM     Sun, May 17, 2015  11:15 PM
  Tue, Jun  2, 2015  11:21 AM     Tue, Jun 16, 2015   9:07 AM
  Wed, Jul  1, 2015   9:22 PM     Wed, Jul 15, 2015   8:26 PM
  Fri, Jul 31, 2015   5:45 AM     Fri, Aug 14, 2015   9:54 AM
  Sat, Aug 29, 2015   1:38 PM     Sun, Sep 13, 2015   1:42 AM
  Sun, Sep 27, 2015   9:52 PM     Mon, Oct 12, 2015   7:06 PM
  Tue, Oct 27, 2015   7:06 AM     Wed, Nov 11, 2015  12:47 PM
  Wed, Nov 25, 2015   5:44 PM     Fri, Dec 11, 2015   5:29 AM
  Fri, Dec 25, 2015   6:11 AM     Sat, Jan  9, 2016   8:31 PM

Why does the Moon have phases?

The Moon has phases because it orbits Earth, which causes the portion we see illuminated to change. The Moon takes 27.3 days to orbit Earth, but the lunar phase cycle (from new Moon to new Moon) is 29.5 days. The Moon spends the extra 2.2 days “catching up” because Earth travels about 45 million miles around the Sun during the time the Moon completes one orbit around Earth.

At the new Moon phase, the Moon is so close to the Sun in the sky that none of the side facing Earth is illuminated (position 1 in illustration). In other words, the Moon is between Earth and Sun. At first quarter, the half-lit Moon is highest in the sky at sunset, then sets about six hours later (3). At full Moon, the Moon is behind Earth in space with respect to the Sun. As the Sun sets, the Moon rises with the side that faces Earth fully exposed to sunlight (5).

You can create a mockup of the relationship between Sun, Earth, and Moon using a bright lamp, a basketball, and a baseball. Mark a spot on the basketball, which represents you as an observer on Earth, then play with various alignments of Earth and Moon in the light of your imaginary Sun.

When is the Harvest Moon?

A harvest moon

The full Moon that occurs closest to the autumnal equinox is commonly referred to as the “Harvest Moon,” since its bright presence in the night sky allows farmers to work longer into the fall night, reaping the rewards of their spring and summer labors. Because the equinox always falls in late September, it is generally a full Moon in September which is given this name, although in some years the full Moon of early October earns the “harvest” designation.

In fact, each full Moon of the year has its own name, most of which are associated with the weather or agriculture. The most common names used in North America include:

• January — Moon after Yule
• February — Snow Moon
• March — Sap Moon
• April — Grass Moon
• May — Planting Moon
• June — Honey Moon
• July — Thunder Moon
• August — Grain Moon
• September — Fruit Moon (or Harvest Moon)
• October — Hunter’s Moon (or Harvest Moon)
• November — Frosty Moon
• December — Moon before Yule

What is a Blue Moon and when is the next one?

Because the time between two full Moons doesn’t quite equal a whole month, approximately every three years there are two full Moons in one calendar month. Over the past few decades, the second full Moon has come to be known as a “blue Moon.” The next time two full Moons occur in the same month (as seen from the United States) will be August 2012. The most recent “blue Moon” occurred in December 2009.

On average, there’s a Blue Moon about every 33 months. Blue Moons are rare because the Moon is full every 29 and a half days, so the timing has to be just right to squeeze two full Moons into a calendar month. The timing has to be really precise to fit two Blue Moons into a single year. It can only happen on either side of February, whose 28-day span is short enough time span to have NO full Moons during the month.

The term “blue Moon” has not always been used this way, however. While the exact origin of the phrase remains unclear, it does in fact refer to a rare blue coloring of the Moon caused by high-altitude dust particles. Most sources credit this unusual event, occurring only “once in a blue moon,” as the true progenitor of the colorful phrase.

Why do we always see the same side of the Moon from Earth?

The Moon always shows us the same face because Earth’s gravity has slowed down the Moon’s rotational speed. The Moon takes as much time to rotate once on its axis as it takes to complete one orbit of Earth. (Both are about 27.3 Earth days.) In other words, the Moon rotates enough each day to compensate for the angle it sweeps out in its orbit around Earth.

Gravitational forces between Earth and the Moon drain the pair of their rotational energy. We see the effect of the Moon in the ocean tides. Likewise, Earth’s gravity creates a detectable bulge — a 60-foot land tide — on the Moon. Eons from now, the same sides of Earth and Moon may forever face each other, as if dancing hand in hand, though the Sun may balloon into a red giant, destroying Earth and the Moon, before this happens.

When does the young Moon first become visible in the evening sky?

There is no real formula for determining the visibility of the young Moon. It depends on several factors: the angle of the ecliptic (the Moon’s path across the sky) with respect to the horizon, the clarity of the sky (how much dust and pollution gunks it up), and even the keenness of the observer’s eyesight.

The young Moon becomes visible to the unaided eye much earlier at times when the ecliptic is perpendicular to the horizon, and the Moon pops straight up into the sky. In these cases, it may be possible to see the Moon as little as 24 hours after it was new, although every hour beyond that greatly increases the chances of spotting it. When the ecliptic is at a low angle to the horizon, and the Moon moves almost parallel to the horizon as it rises, the Moon probably doesn’t become visible until at least 36 hours past new.

The record for the earliest claimed sighting of the young crescent Moon is around 19 hours, although most experts are suspicious of any claims of times less than about 24 hours.

Wet Moon

A wet moon (also called a Cheshire moon and in some cases a West Virginia moon^{[citation needed]}) is a lunar phase when the “horns” of thecrescent moon point up at an angle, away from the horizon. This is caused by the relative angles of the moon’s orbit about the Earth and the Earth’s axial tilt compared to the Sun. During the extreme points of the Earth’s orbit the moon appears to rise almost vertically, so the moon’s crescent takes on the appearance of a bowl or a smile.

Dry moon

During summertime in the northern hemisphere, when the hemisphere tilts towards the Sun, the side of the Earth at nightfall is pointed away from the moon’s orbit, making the lunar path appear closer to thesouthern horizon. This effect also causes the moon to appear lower in the night sky.

Wet moon/Cheshire moon

This process is reversed during wintertime in the northern hemisphere, causing the moon’s path to appear nearly vertical to the western horizon, as well as causing the moon to appear higher in the night sky.