150 years ago this week, the hopes of the Confederacy died beneath the light of the moon.

And just when things seemed brightest.  At the Battle of Chancellorsville in northern VA, Robert E. Lee achieved one of the most noteworthy victories in American military history.  He had been outmaneuvered by the northern army led by “Fighting Joe” Hooker.  But at the critical moment, Fighting Joe lost his nerve and adopted a defensive position in a thick forest.  Lee took the initiative and – breaking a cardinal military rule – split his forces in the face of Hooker’s larger army.  Lee sent Stonewall Jackson and his famed “foot cavalry” on a rapid march around the enemy’s flank.  It was done silently and worked perfectly, and Hooker was taken completely by surprise.  Suddenly, as if out of a nightmare, the terrifying rebel yell echoed out of the trees to Hooker’s right, and thousands of confederate soldiers came crashing through the trees.

In an instant, the entire right flank of the union army disintegrated.  The rest of the northern forces, caught between Jackson to their right and Lee now attacking from their front, ran for their lives.  The southerners surged forward while the northerners tried to regain their discipline.  The two armies became jumbled and confused in the thick forest, the noise and the smoke.  Pandemonium ensued.  Disorganized fighting went on for hours, and only halted when darkness fell.  The south had won a massive victory, but Stonewall Jackson wanted more.  He rode forward on a night reconnaissance to see if he could press the issue further.  While returning back to his own lines – coming from the direction of the northern forces – he was mistaken for a union officer.  His own men opened fire.  Stonewall was hit by three bullets, two in the left arm and one in the right hand.  He was taken to the surgeon, who amputated his shattered arm.  Stonewall survived the operation, but he soon developed pneumonia, and 8 days later he was dead.

This week there was a final coda to this legendary story.  In the latest issue of Sky and Telescope Magazine, two astronomers have published the results of their research into the death of Stonewall at Chancellorsville. Using sophisticated software, they calculated the moon’s lunar phase and position, and plotted the exact locations of Stonewall and the 18^th North Carolina regiment that fired on him, at the fateful moment of 9PM on May 2, 1863.  They cross-referenced these positions with battle maps created by military historians, almanacs from the Virginia Historical Society, and eyewitness accounts of the shooting.  Given these inputs, they have concluded that, from the perspective of the southern soldiers, Stonewall Jackson had a bright moon shining behind him, and would have appeared as a menacing silhouette riding at them through the trees.  They had no choice but to open fire, and only once they had brought Stonewall down would they have learned to their horror what they had done.

Thus a rising moon crowned Lee’s greatest victory with the South’s greatest loss.  Two months later, Stonewall’s absence would be profoundly felt when the South suffered a fatal defeat at Gettysburg.  The confederacy would sense that their cause was waning, and would be left to ponder the dying words of Stonewall Jackson:

“Let us cross over the river and rest beneath the shade of the trees.”