ZTF J222932.52+523047.4: Refined ephemeris from ZTF DR + C82 pre-survey photometry (2016–2026)

Refined orbital ephemeris of ZTF J222932.52+523047.4 (VSX OID 2134559), an Algol-type eclipsing binary in the AG Lacertae field, based on ten years of combined photometry: 1334 ZTF r-band measurements from IPAC/IRSA (2018–2026) One pre-ZTF time of minimum from unfiltered CCD photometry obtained at the C82 Observatory (Osservatorio Astronomico "Nastro Verde", Sorrento, Italy) on 2016-08-13, ~2 years before the ZTF survey began Main results: Quantity Value Period P 1.579152223 ± 8.8×10⁻⁷ d T₀ (Min I) HJD 2458370.78599 ± 0.0006 r_ZTF at quiescence 17.32 mag Min I depth (r) 0.473 mag Min II depth (r) 0.049 mag (centred at phase 0.5 → circularised orbit) Baseline 10.3 yr The automated Chen et al. (2020) ephemeris in VSX (P = 1.5792374 d) is shown to be too long by 7.4 s; propagated backwards to the 2016 C82 epoch this produces a +59 min offset that had been mistaken for a real O−C. Under the refined ephemeris the C82 ToM has O−C = +2.4 ± 2.5 min, consistent with zero. No secular variation is detected. The archive includes raw C82 and ZTF light curves, the 8 seasonal ToMs, four figures, and a fully reproducible Python analysis pipeline.