{
  "reviewed": "2026-11-11",
  "status": "Exploratory date/footprint screen and descriptive multi-eclipse comparison; no causal fit",
  "geometry": [
    {
      "date": "1982-01-09",
      "greatest_ut1": "19:55:51.2",
      "sun_ra_deg": 290.8279166666667,
      "sun_declination_deg": -22.060055555555557,
      "approximate_subsolar_longitude_deg": -117.16115,
      "terminator_max_abs_latitude_deg": 67.93994,
      "method": "Spherical solar-centre terminator; GMST with geocentric solar coordinates. Nutation, oblateness, solar disk, atmospheric refraction and lunar-pixel ray selection omitted; screening only."
    },
    {
      "date": "1982-07-06",
      "greatest_ut1": "07:30:54.5",
      "sun_ra_deg": 105.10875,
      "sun_declination_deg": 22.714055555555554,
      "approximate_subsolar_longitude_deg": 68.4206,
      "terminator_max_abs_latitude_deg": 67.28594,
      "method": "Spherical solar-centre terminator; GMST with geocentric solar coordinates. Nutation, oblateness, solar disk, atmospheric refraction and lunar-pixel ray selection omitted; screening only."
    },
    {
      "date": "1982-12-30",
      "greatest_ut1": "11:28:44.3",
      "sun_ra_deg": 279.18708333333336,
      "sun_declination_deg": -23.172361111111112,
      "approximate_subsolar_longitude_deg": 8.41906,
      "terminator_max_abs_latitude_deg": 66.82764,
      "method": "Spherical solar-centre terminator; GMST with geocentric solar coordinates. Nutation, oblateness, solar disk, atmospheric refraction and lunar-pixel ray selection omitted; screening only."
    }
  ],
  "events": [
    {
      "date": "1963-12-30",
      "retained_rows": 615,
      "represented_timings": 615,
      "weighted_mean_nel_km": 87.1463,
      "row_mean_nel_km": 87.1463,
      "median_nel_km": 83,
      "centre_rows": 615,
      "centre_mean_nel_km": 87.1463,
      "centre_ingress_mean_km": 86.8523,
      "centre_egress_mean_km": 88.4386,
      "limb_mean_km": null,
      "edge_mean_km": null,
      "centre_reporting_label_groups": 66,
      "equal_reporting_label_mean_km": 90.0828
    },
    {
      "date": "1982-01-09",
      "retained_rows": 469,
      "represented_timings": 469,
      "weighted_mean_nel_km": 93.5757,
      "row_mean_nel_km": 93.5757,
      "median_nel_km": 88,
      "centre_rows": 44,
      "centre_mean_nel_km": 94,
      "centre_ingress_mean_km": 113.3529,
      "centre_egress_mean_km": 81.8148,
      "limb_mean_km": 76.44,
      "edge_mean_km": 94.6,
      "centre_reporting_label_groups": 6,
      "equal_reporting_label_mean_km": 103.2
    },
    {
      "date": "1982-07-06",
      "retained_rows": 1164,
      "represented_timings": 1164,
      "weighted_mean_nel_km": 90.7277,
      "row_mean_nel_km": 90.7277,
      "median_nel_km": 87.5,
      "centre_rows": 674,
      "centre_mean_nel_km": 94.0267,
      "centre_ingress_mean_km": 92.1491,
      "centre_egress_mean_km": 100.5298,
      "limb_mean_km": 74.0357,
      "edge_mean_km": 88.7044,
      "centre_reporting_label_groups": 65,
      "equal_reporting_label_mean_km": 94.0925
    },
    {
      "date": "1982-12-30",
      "retained_rows": 535,
      "represented_timings": 535,
      "weighted_mean_nel_km": 80.9626,
      "row_mean_nel_km": 80.9626,
      "median_nel_km": 76,
      "centre_rows": 347,
      "centre_mean_nel_km": 80.7406,
      "centre_ingress_mean_km": 80.9418,
      "centre_egress_mean_km": 79.6727,
      "limb_mean_km": 75.8182,
      "edge_mean_km": 83.0694,
      "centre_reporting_label_groups": 35,
      "equal_reporting_label_mean_km": 84.5241
    },
    {
      "date": "1989-08-17",
      "retained_rows": 1080,
      "represented_timings": 1119,
      "weighted_mean_nel_km": 82.1707,
      "row_mean_nel_km": 82.4741,
      "median_nel_km": 80.0,
      "centre_rows": 690,
      "centre_mean_nel_km": 82.2261,
      "centre_ingress_mean_km": 84.2983,
      "centre_egress_mean_km": 79.0221,
      "limb_mean_km": 80.5972,
      "edge_mean_km": 83.4371,
      "centre_reporting_label_groups": 53,
      "equal_reporting_label_mean_km": 84.4766
    }
  ],
  "sample_profiles": [
    {
      "table": "A2",
      "date": "1982-10-19",
      "start_gmt": "07:13",
      "end_gmt": "07:33",
      "start_lat": 37.3,
      "end_lat": 37.1,
      "start_lon": -78,
      "end_lon": -80,
      "printed_page": 31,
      "days_before_december_eclipse": 72,
      "historical_location_zenith_angle_at_dec30_greatest_deg": 101.826,
      "distance_from_solar_centre_terminator_deg": 11.826
    },
    {
      "table": "A25",
      "date": "1982-10-31",
      "start_gmt": "04:36",
      "end_gmt": "04:43",
      "start_lat": 1.3,
      "end_lat": 1.6,
      "start_lon": -80.6,
      "end_lon": -80,
      "printed_page": 77,
      "days_before_december_eclipse": 60,
      "historical_location_zenith_angle_at_dec30_greatest_deg": 89.393,
      "distance_from_solar_centre_terminator_deg": 0.607
    },
    {
      "table": "A43",
      "date": "1982-11-08",
      "start_gmt": "00:40",
      "end_gmt": "01:01",
      "start_lat": 40.2,
      "end_lat": 39.7,
      "start_lon": -83,
      "end_lon": -80.4,
      "printed_page": 113,
      "days_before_december_eclipse": 52,
      "historical_location_zenith_angle_at_dec30_greatest_deg": 104.722,
      "distance_from_solar_centre_terminator_deg": 14.722
    }
  ],
  "sources": [
    {
      "id": "lidar-full",
      "title": "McCormick & Osborn \u00b7 NASA-RP-1136",
      "url": "https://ntrs.nasa.gov/citations/19850011240",
      "locator": "Printed pp.1\u20132, Table A1 p.30; Tables A2\u2013A43 pp.31\u2013114",
      "scope": "Full report examined for campaign dates, sampled profile headers, method and errors; not all OCR numeric bins validated."
    },
    {
      "id": "noaa-flights",
      "title": "NOAA GMCC Summary Report 1983 \u00b7 section 4.8",
      "url": "https://gml.noaa.gov/publications/summary_reports/summary_report_12.pdf#page=110",
      "locator": "Printed pp.99\u2013100, Figure 79",
      "scope": "Figure 79 visually verified: campaign 2, 4 December 1982\u20134 January 1983, 110\u2013130\u00b0W. Aggregate curve; individual flight times and points not recovered."
    },
    {
      "id": "smithsonian-dec",
      "title": "Smithsonian SEAN Bulletin \u00b7 December 1982 atmospheric report",
      "url": "https://volcano.si.edu/showreport.cfm?doi=10.5479/si.GVP.SEAN198212-600100",
      "locator": "Balloon, aircraft and eclipse paragraphs",
      "scope": "Reports Wyoming balloon data dated 30 December; no exact launch time or full numerical profile supplied. Describes July and December eclipse darkening; qualitative, not calibrated photometry."
    },
    {
      "id": "keen",
      "title": "Keen (1983) \u00b7 Volcanic aerosols and lunar eclipses",
      "url": "https://pubmed.ncbi.nlm.nih.gov/17776243/",
      "locator": "Abstract, DOI 10.1126/science.222.4627.1011",
      "scope": "21-eclipse brightness study located; abstract reviewed. Eclipse-derived aerosol estimates are not independent atmospheric witnesses to the same eclipse brightness."
    },
    {
      "id": "noaa-request",
      "title": "NOAA \u00b7 volcanic radiation data bibliography",
      "url": "https://gml.noaa.gov/grad/volcano.html",
      "locator": "Dutton & DeLuisi 1983a; NOAA Data Report ERL ARL-12 (1987)",
      "scope": "Identifies the precise paper and data report to request for original dated optical-depth observations."
    },
    {
      "id": "rotation",
      "title": "NASA \u00b7 Computational Case Study",
      "url": "https://ntrs.nasa.gov/api/citations/20160000809/downloads/20160000809.pdf",
      "locator": "Equations 16\u201319, p.7",
      "scope": "GMST-to-longitude relation used for approximate footprint screening, not atmospheric ray tracing."
    },
    {
      "id": "catalogue",
      "title": "CDS VI/140 \u00b7 retained crater timing catalogue",
      "url": "https://cdsarc.cds.unistra.fr/viz-bin/ReadMe/VI/140?format=html&tex=true",
      "locator": "crater_t.dat; doc.txt",
      "scope": "Five selected eclipse dates; public catalogue has 22,539 retained rows for 94 events. Weighted means account for represented timings; subgroup means are unweighted rows."
    },
    {
      "id": "paper",
      "title": "Herald & Sinnott (2014) \u00b7 Analysis of lunar eclipse crater timings",
      "url": "https://articles.adsabs.harvard.edu/pdf/2014JBAA..124..247H",
      "locator": "Printed pp.250\u2013253",
      "scope": "Prior 94-eclipse analysis; same timing lineage as catalogue, not independent replication. No statistically significant darkness\u2013shadow-size correlation reported."
    },
    {
      "id": "geometry-1982-01-09",
      "title": "Espenak \u00b7 1982-01-09 eclipse geometry",
      "url": "https://eclipsewise.com/lunar/LEprime/1901-2000/LE1982Jan09Tprime.html",
      "locator": "Geocentric coordinates; greatest UT1",
      "scope": "Retrospective DE405/Danjon predictions. Eclipse Predictions by Fred Espenak, www.EclipseWise.com"
    },
    {
      "id": "geometry-1982-07-06",
      "title": "Espenak \u00b7 1982-07-06 eclipse geometry",
      "url": "https://eclipsewise.com/lunar/LEprime/1901-2000/LE1982Jul06Tprime.html",
      "locator": "Geocentric coordinates; greatest UT1",
      "scope": "Retrospective DE405/Danjon predictions. Eclipse Predictions by Fred Espenak, www.EclipseWise.com"
    },
    {
      "id": "geometry-1982-12-30",
      "title": "Espenak \u00b7 1982-12-30 eclipse geometry",
      "url": "https://eclipsewise.com/lunar/LEprime/1901-2000/LE1982Dec30Tprime.html",
      "locator": "Geocentric coordinates; greatest UT1",
      "scope": "Retrospective DE405/Danjon predictions. Eclipse Predictions by Fred Espenak, www.EclipseWise.com"
    }
  ],
  "test": {
    "question": "Does an unusually dark, aerosol-affected eclipse necessarily have a larger inferred shadow?",
    "selection": "Three 1982 events plus 1963-12-30 volcanic-dark comparison and 1989-08-17 published contrast; retrospective selected examples, not a random or holdout sample.",
    "result": "No simple necessary ordering: December 1982 weighted NEL 80.96 km is lower than July 90.73 and pre-El-Chichon January 93.58. This challenges a simple dark-means-larger claim in these examples; it does not estimate aerosol causation or reject brightness effects.",
    "limits": "No independently matched ray-path AOD or calibrated pixel photometry; no regression, p-value or prediction claimed. Selection bounds, repeated reporters and unbalanced event types remain."
  },
  "matching": {
    "nasa_gmt_start": "1982-10-19",
    "nasa_gmt_end": "1982-11-08",
    "december_gap_days": [
      52,
      72
    ],
    "same_day_balloon": "Reported at Wyoming 41\u00b0N on 30 December; launch time, precise position and numerical series needed.",
    "nearby_flight_campaign": "NOAA Figure 79: 4 December 1982\u20134 January 1983 at 110\u2013130\u00b0W. Campaign overlaps event; no individual flight established as coincident.",
    "next_files": [
      "Wyoming 30 December 1982 balloon launch UTC, coordinates, pressure/temperature, size-distribution bins and calibration",
      "NOAA ERL ARL-12 flight-by-flight timestamps, coordinates, wavelengths, AOD, uncertainty and flags",
      "Calibrated eclipse images or pixel photometry with UTC, passband, lunar position and extinction correction",
      "Daily ozone, cloud and aerosol fields along traced tangent paths; no reanalysis substituted silently for unavailable aerosol data"
    ]
  }
}