Monday, June 20, 2016

Full Moon Summer Solstice


http://buhlplanetarium.tripod.com/pix/graphics/solsticeimage008.png
This diagram shows the position of the Earth, in relation to the Sun, at the time of the Summer Solstice, as well as the other solstice and equinoxes of the year. This year, June's Full Moon occurs on the day of the Summer Solstice in the Western Hemisphere.
(Graphic Source: ©1999, Eric G. Canali, former Floor Manager of Pittsburgh's original Buhl Planetarium and Institute of Popular Science and Founder of the South Hills Backyard Astronomers amateur astronomy club; permission granted for only non-profit use with credit to author.)
 

By Glenn A. Walsh
Reporting for SpaceWatchtower

This year, the beginning of Summer in the Northern Hemisphere is marked with a Full Moon. Both astronomical events occur on the same calendar date in the Western Hemisphere.

For 2016, the season of Summer begins in Earth's Northern Hemisphere (and the season of Winter begins in the Southern Hemisphere) at the moment of the June Solstice: Monday Evening, 2016 June 20 at 6:34 p.m. Eastern Daylight Saving Time (EDT) / 22:34 Coordinated Universal Time (UTC). The actual time of Full Moon occurs Monday morning at 7:02 a.m. EDT / 11:02 UTC, the time of the posting of this blog post. Although, technically, the Moon will be in the Waning Gibbous Phase at the moment of the Summer Solstice, it will, of course, look quite full.

A honey-hued-color Full Moon (particularly at extreme northern latitudes) in June, particularly around the time of the Summer Solstice, is considered the "Honey-Moon." This honey-hued effect is due to the Full Moon traveling low in the sky, very close to the southern horizon, throughout the night.

This may have led to the traditional term of "Honey-Moon," as weddings were traditionally held in June when the good weather days of Summer would begin. The term "Honey-Moon" can be traced as far back as 1552. At that time, marriage was compared to the phases of the Moon, with a Full Moon analogous to the wedding, the most happy time of a relationship.

Although the Full Moon does not occur on the Summer Solstice every year, the June Full Moon does travel close to the southern horizon, throughout the night, every year. As this is the time when the Sun is the highest in the sky for the entire year, this is also the time when the Moon is the lowest in the sky for the entire year.

On days around the time of the Summer Solstice this year, as the Full Moon sets early in the morning in the southwest, the Sun rises at about the same time in the northeast, on the opposite side of the celestial sphere. Likewise, when the Sun sets in the evening in the northwest, at about the same time the Full Moon will be rising in the southeast, on the opposite side of the celestial sphere. And, the locations of the rising and setting of the June Full Moon this year are approximately the same as the locations of the rising and setting of the Sun around the time of the Winter Solstice (December 20 to 22).

In etymology, the word solstice comes from the Latin terms sol (Sun) and sistere (to stand still). In ancient times, astronomers / astrologers / priests recognized that on one day of the year (in the Northern Hemisphere, near the day we now call June 21), the Sun would appear to reach its highest point in the sky for the year. The motion of the Sun's apparent path in the sky (what is known astronomically, today, as the Sun's declination) would cease on this day, before appearing to reverse direction.

Today, we know that, while the Sun does have motions, it is actually the motion of the Earth tilted on its axis 23.43715 degrees / 23 degrees 26 minutes 13.7 seconds away from the plane of the ecliptic (Earth's orbital plane around the Sun), while revolving around the Sun, that causes the Earth's seasons. Hence, as the Earth arrives at the point in its orbit around the Sun, when the north polar axis is most directly inclined toward the Sun, this marks the Summer Solstice in the Northern Hemisphere and the Winter Solstice in the Southern Hemisphere.

Alternately, the Winter Solstice in the Northern Hemisphere occurs when the Earth reaches the point in its orbit when the North Pole is most directly inclined away from the Sun. And, conversely, at this time Summer begins in the planet's Southern Hemisphere.

Although the Summer months in the Northern Hemisphere are known for the year's warmest weather, the Earth is actually at the point in its orbit farthest from the Sun (astronomically known as the point of aphelion) around July 5; the Earth's closest approach to the Sun (perihelion) each year is around January 2. Solar radiation, and hence the heat from the Sun, depends on the length of daylight and the angle of the Sun above the horizon. The tilt of the planet's axis toward the Sun determines the additional and more direct solar radiation received by a planet's Northern or Southern Hemisphere, and hence, the warmer season of the respective hemisphere.

The Vernal Equinox, when the season of Spring begins in the Northern Hemisphere (and the season of Autumn begins in the Southern Hemisphere), occurs between the Winter and Summer Solstices when the Earth reaches the point in its orbit around the Sun when the Earth's axis is inclined neither toward nor away from the Sun. Likewise, when the Earth reaches the point in its orbit around the Sun, between the Summer and Winter Solstices, when the Earth's axis is inclined neither toward nor away from the Sun, this is known as the Autumnal Equinox (beginning of Fall or Autumn) in the Northern Hemisphere; at this time Spring begins in the Southern Hemisphere. And, half-way between the beginning points of each season are Cross-Quarter Days, each related to traditional holidays: Groundhog Day (February 2), May Day (May 1), Lammas Day (traditionally, the first harvest festival of the year on August 1), and Halloween (October 31).

In ancient times, the Summer Solstice was known as Midsummer Day, in early calendars observed around June 24. Such early European celebrations were pre-Christian in origin. Many will associate this ancient holiday with the famous William Shakespeare play, “A Midsummer Night's Dream.” Some speculate that the play was written for the Queen of England, to celebrate the Feast Day of Saint John.

As with the Roman Catholic Church's decision to Christianize the pagan Winter Solstice festivals with the introduction of Christmas Day on December 25, the Church began to associate the Midsummer festivals with the Nativity of Saint John the Baptist on June 24. In the Bible, the Gospel of Saint Luke implies that John was born six months before the birth of Jesus, although no specific birth dates are given.

In addition to the Summer Solstice Full Moon being considered the “Honey-Moon,” to the Algonquin Indians of North America, the June Full Moon was known as the Strawberry Moon. This was due to the relatively short harvest season for strawberries, which always came in June.

In the Northern Hemisphere, the June Full Moon is also known as the Flower Moon and the Corn-Planting Moon. In Europe, the June Full Moon was known as the Rose Moon.

In the Southern Hemisphere, where the season of Winter is about to begin, the June Full Moon is known as the Oak Moon, Cold Moon, and Long-Night's Moon.
 
Links to Additional Information ---

Slooh Community Observatory live web-cast of Full Moon rising on the Summer Solstice - Monday Evening, 2016 June 20, 8:00 to 9:30 p.m. EDT / June 21, 0:00 to 1:30 UTC:
Link >>> http://live.slooh.com/stadium/live/june-solstice-full-moon

More on the Summer Solstice -
Link 1 >>> http://scienceworld.wolfram.com/astronomy/SummerSolstice.html
Link 2 >>> http://en.wikipedia.org/wiki/Summer_solstice

More on the Season of Summer: Link >>>
http://en.wikipedia.org/wiki/Summer

More on the history of Midsummer: Link >>>
http://en.wikipedia.org/wiki/Midsummer

Summer "Solstice Day" Annual Free-of-Charge Day, 1985 to 1991, at Pittsburgh's original Buhl Planetarium and Institute of Popular Science (a.k.a. Buhl Science Center):

Link >>> http://spacewatchtower.blogspot.com/2015/06/snowballs-on-first-day-of-summer.html

Special Thanks: Eric G. Canali, former Floor Manager of Pittsburgh's original Buhl Planetarium and Institute of Popular Science and Founder of the South Hills Backyard Astronomers amateur astronomy club.

Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss.
             2016 June 20.


                                                               Historic 10-inch Siderostat-type Refractor Telescope at Pittsburgh's original Buhl Planetarium and Institute of Popular Science.
        2016: 75th Year of Pittsburgh's Buhl Planetarium Observatory
     Link >>> http://spacewatchtower.blogspot.com/2016/01/astronomical-calendar-2016-january.html

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Glenn A. Walsh, Project Director,
Friends of the Zeiss < http://buhlplanetarium.tripod.com/fotz/ >
Electronic Mail - < gawalsh@planetarium.cc >
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Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
  < http://www.planetarium.cc >
* Adler Planetarium, Chicago:
  < http://adlerplanetarium.tripod.com >
* Astronomer, Educator, Optician John A. Brashear:
  < http://johnbrashear.tripod.com >
* Andrew Carnegie & Carnegie Libraries:
  < http://www.andrewcarnegie.cc >
* Civil War Museum of Andrew Carnegie Free Library:
  < http://garespypost.tripod.com >
Duquesne Incline cable-car railway, Pittsburgh:
  < http://inclinedplane.tripod.com >
* Public Transit:
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