Template:Selected anniversaries/May 15
1579: Mathematician and physicist Thomas Fincke invents new type of scrying engine which pre-visualizes tangents and secants. He will use the engine to detect and expose crimes against mathematical constants.
1618: Johannes Kepler confirms his previously rejected discovery of the third law of planetary motion (he first discovered it on March 8 but soon rejected the idea after some initial calculations were made).
1801: Mathematician Joseph Ludwig Raabe born. He will discover Raabe's ratio test, which determines the convergence or divergence of an infinite series, in some cases.
1836: Astronomer Francis Baily observes "Baily's beads" during an annular eclipse.
1888: Council of algorithms announces plans to fund and build a Museum of Algorithms.
2018: News study suggests that Greedy coloring algorithms "have been systematically corrupted by a consortium of math criminals including Anarchimedes, Forbidden Ratio, and parties as yet uncounted and unidentified."