Astronomical Images : Stars in a region of Aquarius

Johannes Hevelius

Astronomical Images

<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 discussed how to grind lenses, and how to construct instruments using those lenses, Hevelius then presents the results of using his telescope. He shows a small section (the section where water streams out of the jar) of the constellation Aquarius, where A to F indicate the stars from Johannes Bayer's <i>Uranometria</i> (1603). Hevelius emphasises the great diligence and labour with which he found thirty-three additional (fixed) stars in the region and measured their longitudes, latitudes and mutual distances. The signature '<i>Auctor sculpsit</i>' (the author engraved) at the bottom right corner suggests that the positions of these stars were mapped accurately onto the copper-plate. The diagram at the top left, showing Jupiter and newly discovered fixed stars around it, belongs to a refutation Hevelius makes a little later against Antonius Maria Schyrlaeus of Rheita, who claimed to have found five new satellites of Jupiter.</p>