Unusual 1615 in the life of Johannes Kepler

1615 was for Kepler a strange year indeed, marked with happiness, discovery and disillusion. Happiness, because after two years widowhood he got once again married, and to a very nice woman. Discovery, because on the occasion of his buying wine, he determined and proved which were the optimal barrels. Disillusion, because he was obliged to take upon himself all expenses for the printing of this study.