A Tetrad of Lunar Eclipses Starts April 15, 2014.
A series of four lunar eclipses spaced 6 months apart will begin on April 15th, and all of the eclipses will be visible for much of the United States.
The dates are …
April 15, 2014
October 8, 2014
April 4, 2014
September 28, 2015
A tetrad is the term that describes when four total lunar eclipses occur consecutively. They occur in approximately 6-month intervals. There are different types of lunar eclipses — some are partial (a partial shadow crosses the moon), some are penumbral (hardly noticeable because the moon only dims), and a total eclipse when the entire moon is covered by a shadow, but a period of scattered light hits the moon to turn is sunset red or “blood” red. These type of eclipses can arrive in any combination. Sometimes four total eclipses happen consecutively. A period of four total eclipses or a tetrad starts April 15, 2014, but in the Chicago area it actually starts just before midnight on April 14, 2014.
The total eclipse for the Western Hemisphere that begins the Tetrad will begin at 11:53 p.m. CDT April 14, 2014. A darkening on the upper left edge won’t appear until about 12:58 a.m. April 15, 2014 as the earth’s shadow covers the full moon.
At 2:06 a.m. CDT, the eclipse will reach totality, and sunlight that is bent by earth’s atmosphere produces the reddish glow on the moon.
Studying the Eclipse Over the Centuries
Giovanni Schiaparelli discovered that there are eras when tetrads occur frequently, — interrupted by eras when they are rare. This cycle takes about 6 centuries. Antonie Pannekoek (1951) explained this phenomenon and found a period of 591 years. Van den Bergh (1954) found a period of 586 years. This also happens to be an eclipse cycle, but recently Tudor Hughes explained the variation as secular changes in the eccentricity of the Earth’s orbit. The period for occurrence of tetrads is variable and currently is about 565 years.
NIGHT SKY FOR APRIL …
Close Mars, Lunar Eclipse And Lyrid Meteors – April 2014 Skywatching Video.
You can check the moon phases any time here …
Moon Phases for 2014 from NASA Goddard Space Flight Center Scientific Visualization Studio.
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