- In 1611, Johannes Fabricius and his father observed sunspots directly through a telescope shortly after sunrise or before sunset. They discovered that the Sun rotates by recording how sunspots moved around https://www2.hao.ucar.edu/education/scientists/johannes-fabricius-1587-1616 4 comments space
- Johannes Hevelius had exceptionally keen eyesight and could see stars of the seventh magnitude. He compiled a "Celestial Atlas" using both instruments, naked eye observations, and observed sunspots to accurately determine the solar rotation https://www2.hao.ucar.edu/education/scientists/johannes-hevelius-1611-1687 3 comments space
- Astronomer Thomas Harriot observed the Sun directly through a telescope and left nearly 200 drawings of sunspots from the period 1610–1612. To protect his eyes, he took advantage of mist and fog to dim the Sun's brightness https://www2.hao.ucar.edu/education/famoussolarphysicists/harriots-drawings-and-observations 3 comments space