3201 Sijthoff (6560 P-L) is a main-belt asteroid discovered on September 24, 1960 by Cornelis Johannes van Houten, Ingrid van Houten-Groeneveld and Tom Gehrels at Palomar Observatory.The asteroid is named after Albert Georg Sijthoff, publisher of the Haagsche Courant, who promoted the popularization of astronomy in the Netherlands. The Sijthoff family backed the 1934 construction of the Sijthoff Planetarium in the Hague which burned down in 1975 and was replaced by the Omniversum.