Thursday, September 24, 2015

Total Eclipse of a Super(Blood)Moon (on Sept. 27, 2015)

Copyright © Françoise Herrmann

Now… remember to watch the sky on September 27, 2015 when there will be a Total Eclipse of a Super(Blood)Moon. A Supermoon is a Full Moon or New Moon, at its closest position or perigee relative to earth, when the moon appears 12 to 14% bigger than a Micromoon. A BloodMoon is a moon positioned behind the earth, which has obstructed the sun’s blue rays.

From the perspective of the Earth, an eclipse happens when three celestial bodies are aligned almost in a straight line. The alignment is called a zyzygy (from the Greek word meaning "to be paired together").  In the case of a total eclipse of the moon, the sun, moon and earth are all aligned with the moon behind the earth, and the earth sandwhiched between the sun and moon. The earth thus obstructs light coming from the sun, casting its shadow on the moon. The eclipse occurs as the shadow is cast, partially or totally.

 In contrast, in a total eclipse of the sun, the sun, earth and moon are also aligned, but it is the moon that is sandwhiched between the sun and the earth, and it is the moon that casts its shadow on earth, obstructing sunlight during the eclipse. This is why it is almost as dark as night during a total eclipse of the sun, occurring during the day. The next total ecliipse of the sun viewable in the US is on August 21, 2017.

There have only been 5 Total eclipses of a Super(Blood)Moon since 1900. After Sept. 27, 2015, the next one will happen in 2033… So, mark your calendars and set your alarm clocks to 7:47 pm (in California) for viewing the maximum eclipse! 

No eye protection is required for viewing a total eclipse of a Super(Blood)moon. (Eye protection is only required for viewing a total eclipse of the sun). 

The video animation from NASA included below shows what you can expect, if the sky is clear… The Supermoon should appear red as the earth will completely filter out the sun’s blue rays, which is why this Supermoon is also called a “Blood Moon”. 

Enjoy the show!

NASA - National Aeronautics and Space Administration

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