Possible Clues:

• Astronomer's company causing harm when Io's not visible
• Polish astronomer who produced a workable model of the solar system
• Polish astronomer d. 1543
• Polish scholar manages to get across runic in translation
• Astronomer is firm: 'Highly injurious to ignore moon'
• Pioneer in heliocentric theory
• He placed the sun at the center of the universe
• Polish astronomer whose theory on the solar system was published in 1543
• Half-hearted policeman, copper in the wrong, upset old scientist
• Renaissance astronomer