Abstract This publication presents QSTH M. 3 as the first calibration atlas of horizon classes within the M-series of the Quantum Structural Theory of Harmony. It follows the public opening of QSTH 8. M. x, the technical alpha closure of QSTH M. 0, the unit-scale audit of QSTH M. 1, and the source review of the older Horizon Set line in QSTH M. 2. The purpose of M. 3 is not to claim a completed physical theory of horizons, nor to prove the M-independent horizon. Its aim is more precise: to examine how known ideal horizon classes behave when mass is scaled out of the account and when the remaining dimensionless signatures are read as regime, state, or closure markers. The document introduces two main axes of the atlas: the horizon closure axis and the R-Signature regime axis. The closure axis is expressed through the Alpha-I-Dim Horizon Closure Equation, alphaI-Dim² * (Sₑff / kB) = pi * kappa (Gamma), while the regime axis is represented by the Planck-normalized thermal-length signature, R = (TH / TP) * (lH / lP). Four primary horizon classes are examined. The de Sitter horizon acts as a reference closure class, giving kappa (Gamma) =1 and Cₜopo=3*pi in the pure cosmological regime. The Schwarzschild horizon provides a thermal-length baseline with R=1/ (4*pi). The Kerr horizon introduces spin modulation through the dimensionless spin parameter a_*, while the Reissner–Nordström horizon provides a charge-modulated theoretical control branch through q_*. Kerr–Newman is retained as a future full classical spin-charge class. A central thesis of M. 3 is that M-independent does not mean state-independent. After the explicit mass scale is removed from selected dimensionless horizon combinations, the horizon does not become empty; it begins to speak through state parameters such as cosmological scale, spin, charge, closure labels, and regime signatures. The publication also includes a Galois brake, reminding that a horizon class is not the full microstate content but a ledger-visible class label after projection, redundancy reduction, orbit grouping, and regime normalization. It concludes with observational channels, status audit, failure modes, and a bridge toward QSTH M. 4, where the closure label kappaR (Gamma) must become a regime-read seal rather than a general symbolic label. Description This record contains the English final version of QSTH M. 3 — Calibration Atlas of Horizon Classes, a calibration-atlas publication in the QSTH M-series. The publication follows QSTH 8. M. x — Horizon Ledger of the Settled Structure, QSTH M. 0 — M-Independent Horizon: Alpha Closure of the Horizon Ledger, QSTH M. 1 — Unit Hygiene and Alpha-I-Dim Audit, and QSTH M. 2 — Source Review of the Older Horizon Set Line. M. 3 develops the first structured atlas of horizon classes for the M-independent horizon framework. It translates the equation layer and genealogy of M. 1/M. 2 into reference horizon regimes: de Sitter, Schwarzschild, Kerr, Reissner–Nordström, and future Kerr–Newman. The document includes: an Epistemic Note / Methodological Brake, a Calibration Brake for the de Sitter reference class, the transition from M. 2 genealogy to M. 3 class calibration, the two axes of the atlas: closure and R-Signature, the Galois brake for horizon classes, de Sitter as the reference closure class, Schwarzschild as the R-Signature baseline, Kerr as a spin-modulated class, Reissner–Nordström as a charge-modulated theoretical class, a first horizon-class table, a class audit table for closure role, R-signature role, and state parameter, possible observational channels such as EHT, ringdown, QPO, and lensing, a status audit, failure modes and skeptical contract, open problems after M. 3, and a bridge toward QSTH M. 4. This publication should be read as a theoretical and methodological calibration atlas. It does not claim empirical confirmation of QSTH or of the M-independent horizon. Its purpose is to define how known horizon classes may serve as calibration regimes for future Horizon Ledger work. Subjects / categories Physics — Theoretical PhysicsMathematical PhysicsQuantum PhysicsCosmology and Nongalactic AstrophysicsInformation Theory Related work note This publication follows QSTH 8. M. x — Horizon Ledger of the Settled Structure, QSTH M. 0 — M-Independent Horizon: Alpha Closure of the Horizon Ledger, QSTH M. 1 — Unit Hygiene and Alpha-I-Dim Audit, and QSTH M. 2 — Source Review of the Older Horizon Set Line. It provides the first horizon-class calibration atlas and prepares the transition toward QSTH M. 4, where kappaR (Gamma) is intended to become a regime-read closure seal. Plain-language summary This publication asks what remains of a horizon when the explicit mass scale is normalized out of selected dimensionless combinations. It shows that M-independent does not mean state-independent: after mass cancellation, horizons still carry class signatures such as cosmological scale, spin, charge, thermal-length regime, and closure labels. M. 3 therefore builds the first calibration atlas of horizon classes for the QSTH M-series. Final Zenodo caveat This document is a theoretical and methodological calibration-atlas publication. It does not claim that QSTH is empirically confirmed, nor does it present the M-independent horizon as an established physical object. The de Sitter, Schwarzschild, Kerr, and Reissner–Nordström classes are used as calibration regimes and conceptual test beds, not as empirical proof of the full QSTH framework. Suggested citation Stepanik, R. (2026). QSTH M. 3 — Calibration Atlas of Horizon Classes. Quantum Structural Theory of Harmony, EN v1. 0 Final / 8. M. x, M. 0, M. 1, M. 2 & Galois Alignment. Zenodo. Copyright Copyright (C) 2026 Rostislav Stepanik
Rostislav Stepanik (Sun,) studied this question.