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Jan Jędrzejewicz was an amateur astronomer who in the 2nd half of the 19th century created an observation centre, which considering the level of research was comparable to the European ones. Jędrzejewicz settled down in Płońsk in 1862 and worked as a doctor ever since but his greatest passion was astronomy, to which he dedicated all his free time. In 1875 Jędrzejewicz finished the construction of...
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