Geological Chronicle
Located on the eastern edge of Mare Fecunditatis, Vendelinus spans 141.21 kilometers across and forms a chain of prominent craters with Langrenus to the north and Petavius to the southeast. Because of its location near the eastern rim, foreshortening gives the ancient impact crater an oblong appearance.
The crater is heavily worn and overlapped by multiple impacts, making the formation difficult to identify except under low sun angles. Its irregular rim is broken in several locations, most prominently by the overlapping crater Lamé in the northeast wall. The smaller crater Lohse overlaps the northwestern rim, while the southern wall joins Holden.
Vendelinus has a flat floor covered by a dark lava flow, where the astronomer Webb observed a dark patch visible during full moon. The crater lacks a central peak and contains multiple impact craters of various dimensions, including oblong secondary craters from Langrenus and a rise on the northeastern floor formed by the outer ramparts of Lamé.
Giovanni Riccioli named the crater after Flemish astronomer Godefroy Wendelin in 1651. The International Astronomical Union formally approved the name in 1935.