David Fabricius

David and Johannes Fabricius were father and son astronomers from Frisia .

David Fabricius ( March 9 , 1564 - May 7 , 1617 ) was responsible for two major discoveries inthe early days of telescopic astronomy . Born in Esens, Frisia, as an adult DavidFabricius (a Latinized version of his proper name David Faber) served as pastor for small towns in Frisia (part ofmodern-day Germany ). As was common for churchmen in those days he dabbled in science;in his particular case the science was astronomy.

Fabricius made his first mark on history by discovering the first known periodic variable star (as opposed to cataclysmicvariables, such as novas and supernovas ), Mira , in August of 1596 . At first he believed it to be "just" another nova, as the whole concept of a recurring variable did not exist atthe time. When he saw Mira brighten again in 1609 , however, it became clear that a new kindof object had been discovered in the sky.

Two years later, his son Johannes Fabricius ( 1587 - 1615 ) returned from university in the Netherlands withtelescopes that they turned on the Sun . Despite the difficulties of observing the sundirectly, they noted the existence of sunspots , the first confirmed instance of theirobservation (though unclear statements in East Asian annals suggest that Chinese astronomers may have discovered them with thenaked eye previously, and Fabricius may have noticed them himself without a telescope a few years before). The pair soon invented camera obscura telescopy so as to save their eyes and get a better viewof the solar disk, and observed that the spots moved. They would appear on the eastern edge of the disk, steadily move to thewestern edge, disappear, then reappear at the east again after the passage of the same amount of time that it had taken for it tocross the disk in the first place.

This suggested that the Sun rotated on its axis, which had been postulated before but never backed up with evidence. Johannespublished Maculis in Sole Observatis, et Apparente earum cum Sole Conversione Narratio ("Narration on Spots Observed onthe Sun and their Apparent Rotation with the Sun") in June of 1611 . Unfortunately, the book remained obscure and was eclipsed (so to speak) by the independent discoveries of andpublications about sunspots by Christoph Scheiner in January 1612 and Galileo Galilei in March 1612.

Besides these two discoveries, little else is known about David Fabricius except his unusual manner of death: after denouncinga local goose thief from the pulpit, the accused man struck him in the head with a shovel and killed him. Copies of a map he madeof Frisia in 1589 are also still extant. He is also name-checked in Jules Verne 's From the Earth to the Moon as someone who claimed to have seenlunar inhabitants through his telescope, though that particular fact is merely part of Verne's fiction.

A large (90 kilometer) crater on the Moon 's southern hemisphere is named after DavidFabricius.