Which German astronomer observed the Jovian moons concurrently, although Galileo published first?

Answer

Simon Marius

The German astronomer Simon Marius also observed these objects around the same time, but Galileo secured the priority of discovery by publishing his results first.

Which German astronomer observed the Jovian moons concurrently, although Galileo published first?
discoveryGalileoastronomyJupiterobservation