January 28: Johannes Hevelius

Johannes Hevelius

January 28, 1611 – January 28, 1687

Johannes Hevelius (Latin), also called Jan Heweliusz (in Polish), was a Polish astronomer. He gained the reputation of "the founder of lunar topography" and invented ten new constellations, seven of which are still recognized by astronomers (Canes Venatici, Lacerta, Leo Minor, Lynx, Scutum, Sextans and Vulpecula).

In 1641 he built an observatory on the roofs of his three connected houses, equipping it with splendid instruments, including ultimately a tubeless telescope of 45 m (150 ft) focal length, constructed by himself.

In May 1679, the young Englishman Edmund Halley visited Hevelius as emissary of the Royal Society. Halley had been instructed by Robert Hooke and John Flamsteed to persuade Hevelius to use telescopes, yet Hevelius demonstrated that he could do well with only quadrant and alidade. He is thus considered the last astronomer to do major work without lenses.

Hevelius made observations of sunspots, 1642–1645, devoted four years to charting the lunar surface, discovered the Moon's libration in longitude, and published his results in Selenographia, sive Lunae descriptio (1647), a work which entitles him to be called "the founder of lunar topography."

He discovered four comets, in 1652, 1661 (probably Ikeya-Zhang), 1672 and 1677. These discoveries led to his thesis that such bodies revolve around the Sun in parabolic paths.

Katharine, his first wife, died in 1662, and a year later Hevelius married Elisabeth Koopmann, the young daughter of a merchant family. The couple had four children. Elisabeth supported him, published two of his works after his death, and is considered the first female astronomer and called "the mother of moon charts". Her life was recently novelized as The Star Huntress (2006).

The Lunar crater Hevelius is named in his honor.