Experience proves that very often the outcome of human activity does not fit the expectations. Very rarely, however, does the wrong result turn into something positive. Nevertheless, this is what happened in the case of a Danish astronomer Tycho Brahe (1546 -- 1601). This most eminent critic of Copernicus' heliocentric theory (and author of a rivaling system) unwillingly contributed to its victory. Namely, his very precise observations of the position of planets - peformed with a precision of 1' at a time when telescopes were still unknown - enabled his student, Johannes Kepler (1571 - 1630), to formulate the well-known laws of the motion of planets which remain a permanent contribution to modern astronomy.

