Johannes was born in
Resterhafe (
East Friesland). He studied at the
University of Helmstedt,
Wittenberg University and graduated from
Leiden University in 1611. He returned from university in the
Netherlands with telescopes that he and his father turned on the
Sun. Despite the difficulties of observing the Sun directly with a telescope, they noted the existence of
sunspots, one of the first confirmed instance of such observations telescopically; sunspots had first been identified without telescopes in ancient China and Greece. Johannes first observed a sunspot on February 27, 1611; in
Wittenberg in that year he published the results of his observations in his 22-page pamphlet
De Maculis in Sole observatis..... It was the first publication on the topic of sunspots. The pair soon used
camera obscura telescopy so as to save their eyes and get a better view of the solar disk, and observed that the spots moved. They would appear on the eastern edge of the disk, steadily move to the western edge, disappear, then reappear at the east again after the same amount of time that it had taken for it to cross the disk in the first place. He is also mentioned in
Jules Verne's 1865 novel
From the Earth to the Moon as someone who claimed to have seen lunar inhabitants through his telescope, though that particular fact is merely part of Verne's fiction. The large ()
Fabricius crater, on the
Moon's southern hemisphere, is named after his father,
David Fabricius. He died in
Marienhafe, at the age of 29. ==Legacy==