The Stammler circle is the circumcircle of the Stammler triangle. Unexpectedly, it has center at the circumcenter O (X_3) of the reference triangle and radius 2R (Ehrmann and van Lamoen 2002). It has circle function l = - (3a^2 b c)/(16Δ^2), where Δ is the area of the reference triangle. The circle passes through the Parry reflection point X_399.

central circle | Stammler circles | Stammler triangle