May 10

28 BC - A sunspot is observed by Han dynasty astronomers during the reign of Emperor Cheng of Han, one of the earliest dated sunspot observations in China.
1900 - Cecilia Payne-Gaposchkin is born. She was an astrophysicist who proposed that stars were composed of primarily of hydrogen and helium.

2414 - Tokat is assigned as commanding officer of the USS Pegasus, CL-2500.