{
 "file": "principe.json",
 "kind": "transcription of printed tables (the final stage of the Principe reduction)",
 "what": "The last stage of the Principe reduction as printed: for each of the four eclipse-to-Oxford comparisons, the residual column Delta4y (after the scale, orientation and a provisional Einstein displacement were removed) and the star coefficients a_y; the printed normal equations, corrections and results.",
 "source": {
  "citation": "F. W. Dyson, A. S. Eddington and C. Davidson, \"A determination of the deflection of light by the sun's gravitational field, from observations made at the total eclipse of May 29, 1919\", Philosophical Transactions of the Royal Society of London, Series A, 220 (issues 571 to 581), 291 to 333. Received 30 October 1919, read 6 November 1919, published 27 April 1920. DOI 10.1098/rsta.1920.0009.",
  "doi": "10.1098/rsta.1920.0009",
  "scan_url": "https://astronomyforchange.org/wp-content/uploads/2021/06/DysonOriginalPaper_1919TSE_rsta.1920.0009.pdf",
  "scan_sha256": "f54474b217ab17a3d3bf4754cbe8bf0a1072c7a8f272696d1fb62d0ecc78350d",
  "scan_bytes": 8198432,
  "retrieved": "2026-09-22",
  "licence": "No licence statement on the scan (Royal Society download stamp). Only transcribed numbers, with citation, are shipped; the scan and its page images are not.",
  "pdf_page_note": "PDF page 1 is printed page 291; one plate page is bound in before printed page 293, so printed page p is PDF page p - 289 from page 293 on."
 },
 "pages": {
  "method_and_kappa": "p.322 (PDF 33)",
  "X_G_and_X_H": "pp.323 to 324 (PDF 34 to 35)",
  "W_D_and_W_I": "pp.324 to 325 (PDF 35 to 36)",
  "plate_U": "p.326 (PDF 37)",
  "correction_and_four_results": "p.327 (PDF 38)",
  "final_result": "p.328 (PDF 39)"
 },
 "unit_arcsec": 0.003,
 "kappa_einstein": 184,
 "sun_radius_arcmin": 15.78,
 "einstein_limb_arcsec": 1.75,
 "a_y": {
  "11": 0.03,
  "5": -0.69,
  "4": 1.27,
  "3": 1.48,
  "6": 0.74,
  "10": 0.62
 },
 "comparisons": [
  {
   "id": "X-G",
   "eclipse_plate": "X",
   "oxford_plate": "G1",
   "stars": [
    11,
    5,
    4,
    3,
    6
   ],
   "delta4y": [
    6130,
    6070,
    6262,
    6013,
    6149
   ],
   "printed_normal_equations": [
    [
     5,
     2.83,
     -1
    ],
    [
     2.83,
     4.83,
     64
    ]
   ],
   "printed_dkappa": 20,
   "printed_limb_arcsec": 1.94
  },
  {
   "id": "X-H",
   "eclipse_plate": "X",
   "oxford_plate": "H1",
   "stars": [
    11,
    5,
    4,
    3,
    6
   ],
   "delta4y": [
    1103,
    893,
    954,
    864,
    842
   ],
   "printed_normal_equations": [
    [
     5,
     2.83,
     1
    ],
    [
     2.83,
     4.83,
     -105
    ]
   ],
   "printed_dkappa": -33,
   "printed_limb_arcsec": 1.44
  },
  {
   "id": "W-D",
   "eclipse_plate": "W",
   "oxford_plate": "D1",
   "stars": [
    5,
    4,
    3,
    6,
    10
   ],
   "delta4y": [
    6378,
    6233,
    6417,
    6179,
    6332
   ],
   "printed_normal_equations": [
    [
     5,
     3.42,
     -1
    ],
    [
     3.42,
     5.21,
     -62
    ]
   ],
   "printed_dkappa": -21,
   "printed_limb_arcsec": 1.55
  },
  {
   "id": "W-I",
   "eclipse_plate": "W",
   "oxford_plate": "I2",
   "stars": [
    5,
    4,
    3,
    6,
    10
   ],
   "delta4y": [
    -7296,
    -7389,
    -7247,
    -7308,
    -7163
   ],
   "printed_normal_equations": [
    [
     5,
     3.42,
     2
    ],
    [
     3.42,
     5.21,
     -24
    ]
   ],
   "printed_dkappa": -9,
   "printed_limb_arcsec": 1.67
  }
 ],
 "printed": {
  "mean_of_four_arcsec": 1.65,
  "correction_arcsec": -0.04,
  "limb_arcsec": 1.61,
  "probable_error_arcsec": 0.3
 },
 "plate_U": {
  "limb_arcsec": 2.9,
  "probable_error_arcsec": 0.87,
  "note": "This determination is ignored in the subsequent discussion (p.327)."
 },
 "plates_lost": "Gilmore and Tausch-Pebody 2022: \"The Principe plates have been lost.\""
}