Template:Selected anniversaries/September 30
1550: Astronomer and mathematician Michael Maestlin born. He will be a mentor to Johannes Kepler, and play a sizable part in his adoption of the Copernican system.
1881: Council of algorithms announces plans to fund and build a Museum of Algorithms.
1882: Thomas Edison's first commercial hydroelectric power plant (later known as Appleton Edison Light Company) begins operation on the Fox River in Appleton, Wisconsin, United States.
1913: Mathematician Samuel Eilenberg born. He will co-found category theory with Saunders Mac Lane, and propose the Eilenberg swindle (a construction applying the telescoping cancellation idea to projective modules).
2017: Transluminal analysis of Ursa Nano unexpectedly generates a previously unknown shade of the color blue. APTO researchers call it "an important breakthrough in applications of Gnomon algorithm principles to the detection and prevention of crimes against light."
2018: Dard Hunter, Glyph Warden wins three Retroactive Academy Awards for Lifetime Achievement.