Hardness ratios for the middle (blue), outer (red), and overall (purple) segments of the PN X-ray light curve. The overall light curve was split into thirds, each equal in duration. The outer two segments were concatenated and represent the “outer” segment. The middle third represents the “middle” segment. The “overall” segment includes all continuous counts. For Method 1, hardness ratios were computed from raw photon counts. For Method 2, they were computed from the best-fitting fluxes from the BXA Markov Chain Monte Carlo analysis. The energy bands are as follows: H: 1.0–2.0 keV; M: 0.5–1.0 keV; S: 0.2–0.5 keV; H₂: 1.0–10.0 keV; and S₂: 0.2–1.0 keV.