1612 in science

Astronomy

• The first description of the Andromeda Galaxy based on observations by telescope is given by Simon Marius.
• December 28 – Galileo observes the planet Neptune for the first time when it is in conjunction with Jupiter, but mistakenly catalogues it as a fixed star because of its extremely slow motion along the ecliptic, and it will not be properly identified until 1846.

Medicine

• Santorio Sanctorius puts the thermometer to medical use.

Births

Deaths

• February – John Gerard, English herbalist
• February 6 – Christopher Clavius, German mathematician and astronomer
• February 12 – Jodocus Hondius, Flemish cartographer
• November 20 – Sir John Harington, English inventor