This publication documents the sixty-first chapter of the OS (Operational Structure) System, a long-term research project investigating whether observed physical quantities form a recursive structural network governed by invariant relational operators. The chapter examines the observed Schwarzschild radius of Sagittarius A*, the supermassive black hole at the center of the Milky Way. Unlike conventional model-building approaches, this work introduces: no new constants, no fitted parameters, no optimization, no correction coefficients, no additional structural operators. Instead, the observed radius is evaluated exclusively through structural operators and invariant nodes established in the previous sixty chapters of the OS System. The analysis demonstrates that the measured radius repeatedly returns previously established structural nodes, including the light channel, transition operators, Earth-scale structural regions, recursive transport nodes, and the fine-structure structural network. Within the OS framework, Sagittarius A* does not appear as an isolated object. It integrates into the same recursive hierarchy that previously connected atomic, planetary, stellar, and galactic scales. This chapter extends the existing computation tree without modifying its foundational relations.
Danijus Kazlauskas (Mon,) studied this question.