<p style='text-align: justify;'>The <i>Selenographia</i>, literally meaning 'descriptions of the Moon' was published by Johannes Hevelius (1611-1687) in 1647. In addition to descriptions of the surface of the Moon, the book also contained other telescopic observations by Hevelius, as well as explanations of instruments. The <i>Selenographia</i> is an unusual publication in the extent to which an author controlled the printed presentation of his work. The book contained observations made by Hevelius at his observatory using instruments (several of which he invented or improved upon), drawn and noted down by himself, then engraved by himself ' several images bear the signature: <i>auctor sculpsit</i> (the author engraved) ' and published at his own expense. This avoided complications and errors that might be introduced during the publication process by other artists and printers. The book itself contains a wide range of representations of the Moon, including a series of the surface of the Moon through its phases. Having first discussed the kind of lathe required to grind lenses, Hevelius moves on to discuss different types of 'optical tubes' that use these lenses. He lists four, namely the telescope, the helioscope, the microscope and the polemoscope. The polemoscope invented by Hevelius is like a periscope, a tube fitted with mirrors set at an angle to the line of sight to enable viewing of an object not in the line of sight. Hevelius shows the component parts of this instrument made of brass.</p>
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