On which date did Galileo first observe the three small, bright stars aligned near Jupiter?

Answer

Around January 7th, 1610

Galileo began observing Jupiter around January 7th, 1610, and on that night he noticed three stellar companions aligned near the planet.

On which date did Galileo first observe the three small, bright stars aligned near Jupiter?
discoveryGalileoastronomytelescopeMoon