What is "regiomontanus"

Johannes Müller von Königsberg (6 June 1436 – 6 July 1476), today best known by the Latin epithet Regiomontanus, was a German mathematician, astronomer, astrologer, translator, instrument maker and Catholic bishop.

He was born in the Franconian village of Unfinden, now part of Königsberg, Bavaria — not in the more famous East-Prussian Königsberg.

He was also known as Johannes der Königsberger (Johannes of Königsberg). His writings were published under the name of Ioannes de Monte Regio, a Latinized version of his name. Both names mean "John of King's Mountain". The name "Regiomontanus" was first coined by Philipp Melanchthon in 1534, fifty-eight years after Regiomontanus' death.

Regiomontanus is an ancient lunar impact crater located in the southern highlands region to the southeast of Mare Nubium. It is joined at the chaotic northern rim by the crater Purbach, and to the south-southeast is Walther.