Waning Crescent Moon: Old Moon Signals End of Lunar Cycle via Completed Orbit

Summary: The waning crescent moon, known as an old moon, signals the end of a lunar cycle. In March 2015 the old moon rises on the infamous Ides of March.

Waning crescent moon: NASA Goddard Space Flight Center (NASA Goddard Photo and Video), CC BY 2.0, via Flickr

Staging its entrance for March on Sunday the 15th, the waning crescent moon begins on the Ides of March, Roman classical history's infamous date of the assassination of Gaius Julius Caesar (July 100-March 15, 44 BCE). Moonrise on March 15 happens on the Eastern Seaboard over the U.S. capital of Washington DC at 3:37 a.m. Eastern Daylight Time (7:37 a.m. Coordinated Universal Time).

On Wednesday, March 18, 2015, the waning crescent moon's rising appears low in the east for its final appearance to Northern Hemisphere viewers during the year's third month. On the day after St. Patrick's Day, moonrise occurs over Washington D.C. at 5:55 a.m. EDT. Sunrise happens over an hour later at 7:15 a.m. EDT.

The setting of the waning crescent moon over Washington D.C. on March 18 is timed for 5:31 p.m. EDT. The phase's next appearance is scheduled for Tuesday, April 14.

March 18 also welcomes favorable viewing of Mercury in the Southern Hemisphere. In the Northern Hemisphere, where Mercury rises at 6:34 a.m. EDT, the visibility of the gray planet and of the lunar crescent is likely to be obscured by predawn interference.

The descriptor of waning crescent perfectly applies to this lunar phase. Waning has the meaning of decreasing and diminishing. In this moon phase, the extent of the illuminated lunar surface decreases dramatically. Crescent defines a curved shape with concave and convex edges ending in points.

The waning crescent moon is also known as an old moon because it occurs at the end of the monthly lunar cycle. The waning crescent moon signals that the moon has made a complete orbit of the Earth.

The lunar transition to the next phase as new moon heralds the beginning of a new orbit around the Earth. The monthly lunar cycle acknowledges the moon's continuous circuit around the Earth. The eight-phase monthly lunar cycle begins with the new moon as first phase and ends with the waning crescent moon as eighth phase.

The eight-phase lunar cycle is further delineated into four primary, or principal, phases and four intermediate phases. As the eighth phase, the waning crescent moon is reckoned as the fourth and final intermediate phase.

The waning crescent moon identifies the lunar transition from its predecessor, the last quarter moon to the waning crescent moon's dark successor. The last quarter moon serves as the fourth and final primary phase. The new moon serves as the first phase of the eight-phase lunar cycle and also as the first of each cycle's four primary phases.

The waning crescent moon presents a diminishing illumination within the descending range of 49 to 1 percent. The thin sliver of the cycle's last visible crescent effectively imprints upon Earthlings the nickname of old man for conveying the drastic decline in light.

Differences in the location of the crescent on the lunar surface distinguish viewings above or below the equator. In the Northern Hemisphere, the waning crescent outlines primarily the moon's left edge. In the Southern Hemisphere, the crescent wanes mainly along the moon's right edge.

A waning crescent moon stands out, despite its iconic slim curvature. All the moon's illumination for Earthlings is focused into a shining sliver that casts a sparkling intensity.

The waning crescent moon's beauty inheres in its completed orbit of the Earth. The waning crescent moon comes full circle, closing one circle and opening another.

The steadiness of the lunar journey can reassure Earthlings that events predictably unfold in the vastness of outer space. Each phase of the lunar cycle tells a story of the moon's journey through space and time around the Earth.

The waning crescent moon's tale is a happy ending leading to a fresh beginning.

Waning crescent moon, July 23, 2014: Daniel Oines (dno1967b), CC BY 2.0, via Flickr

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

waning crescent moon, June 15, 2011: NASA Goddard Space Flight Center (NASA Goddard Photo and Video), CC BY 2.0, via Flickr @ https://www.flickr.com/photos/gsfc/5837032862/

waning crescent moon, July 23, 2014: Daniel Oines (dno1967b), CC BY 2.0, via Flickr @ https://www.flickr.com/photos/dno1967b/14537701769/

For further information:

McClure, Bruce. "Old moon before sunrise March 18." EarthSky > March 18-March 24.
Available @ https://earthsky.org/tonight/old-lunar-crescent-low-in-east-before-sunrise-march-18

"Twelve Year Planetary Ephemeris: 1995 - 2006." NASA GSFC > Eclipse Web Site.
Available @ http://eclipse.gsfc.nasa.gov/TYPE/moonphase.html

"Washington DC, U.S.A. - Moonrise, moonset and moon phases, March 2015." Time and Date > Sun & Moon > Moon.
Available @ http://www.timeanddate.com/moon/usa/washington-dc