(CNN) The D-Day allied invasion of Normandy began with paratroopers and soldiers coasting through the air on gliders in the darkness of the early morning hours. And a full moon lit the way.

They landed on the beach first , captured coastal bridges and opened roadways for the incoming fleet carrying troops.

Many historical accounts cite the importance of a late-rising moon in making the airborne assault successful, allowing for secrecy.

However, Texas State University astronomer Donald Olson says these accounts are incorrect and the moon rose early that fateful day. The description of a late-rising moon was counter to statements from General Dwight D. Eisenhower and Prime Minister Winston Churchill. The Allied leaders noted the full moon as key to guiding the way of each stage of the assault between June 5 and 6.

And Olson realized that a late-rising moon didn't match the tide during the invasion. When he used astronomical software, Olson saw that the moon rose early that day.

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