Geological Chronicle
Located within Sinus Medii near the central near side of the Moon, Triesnecker is an impact crater with a diameter of 24.97 kilometers. The structure sits north-northwest of Rhaeticus and east-southeast of the flooded crater Murchison. When the Sun reaches a high angle, a prominent ray system becomes visible, extending over 300 kilometers across the surrounding surface.
The rim of Triesnecker deviates from a circular outline, marked by a notable bulge along its western wall and lesser rises along its southeastern and northeastern rims. Terraced inner walls descend to a rough floor with a central peak at its midpoint. Nineteenth-century observer T. W. Webb recorded that the crater was surrounded by several minute clefts.
Directly east of the formation lies an extensive system of rilles that spans 200 kilometers across and runs generally north–south. Planetary scientists infer that these troughs were likely created by tectonic forces beneath the surface. Beyond to the northeast lies the Rima Hyginus valley with Hyginus at its midpoint. The crater honors Austrian astronomer Franz de Paula Triesnecker.