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Lunar letters

September 2012: A First Quarter Moon offers observers countless targets, including two special letters.
Glenn Chaple
First Quarter or half Moon — which is the correct name of the lunar phase that occurs one week after New Moon? Astronomers prefer the former while poets and dreamers opt for the latter. One of my goals as a middle school science teacher was to stamp “quarter Moon” into the impressionable young minds of my students. I had a tactic. I’d begin by saying, “Notice that First Quarter phase occurs when the Moon has traveled one quarter of the way around Earth since New Moon.” Then I’d add, “During First Quarter, we only see half of the one-half of the Moon that faces Earth. Half of one-half equals one quarter of the entire Moon.” Mission accomplished! Or so I thought.

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