Initial discovery was from images acquired on 23 January 2012 at VATT, on Mount Graham, Arizona using a 1.8 meter reflecting telescope; precovery observations from VATT and the Sloan Digital Sky Survey dating back to 31 December 2002 have been accepted by the Minor Planet Center. The object has been repeatedly tracked through January 2016, mostly by VATT with some supporting observations by Las Campanas Observatory. 420356 Praamzius is one of the most recently discovered minor planets to receive a numeric designation, confirming it as a distinct body with a well determined orbit. This is due to the large number of observations since and indeed before its discovery: about one every 23 to 24 days on average from 2002 to 2016, and as many as one per 10 days in the period between discovery and assignment alone. Precovery images refined the orbit even more.