21st march 1684 discovery of Saturn moon Tethys.
The Italian/French astronomer Cassini discovered Tethys a medium size moon of Saturn which is about 1060 km across. Tethys is named after the Titan Tethys from Greek mythology
On This Day (2)
21st March 1684 discovery of Saturn moon Dione
Cassini discovered not one but two moons on this day, not only did he discover Tethys but also the moon Dione. This moon is slightly larger at 1140 km. Dione is named after the Titan Dione.
On This Day (3)
21st March 1928 death of E W Maunder
Edward Walter Maunder (12 April 1851 – 21 March 1928) was an English astronomer who studied sunspots and discovered the sunspot minimum from 1645 until 1715 which is now referred to as the Maunder Minimum.
The Maunder Minimum